To assess the aquatic ecosystem safety for silica (SiO2) nanoparticles (NPs), the growth inhibition and photosynthetic pigment contents of Scenedesmus obliquus in logarithm growth phase exposed to SiO2 NPs and SiO...To assess the aquatic ecosystem safety for silica (SiO2) nanoparticles (NPs), the growth inhibition and photosynthetic pigment contents of Scenedesmus obliquus in logarithm growth phase exposed to SiO2 NPs and SiO2 bulk particles (BPs) suspensions were measured. SiO2 NPs with 10-20 nm diameters were found to be toxic. The 20% effective concentration (EC20) values for 72 and 96 hr were 388.1 and 216.5 mg/L, respectively. The contents of chlorophyll decreased significantly under moderate and high concentration (50, 100, and 200 mg/L) of SiO2 NPs after 96-hr exposure, but the carotenoids did not. SiO2 BPs were found to be nontoxic up to 200 mg/L. The toxicity of SiO2 NPs probablely due to their sorption to algal cells surface. The results imply that there is potential harm to aquatic environment by using SiO2 NPs, and it should deserve special concern.展开更多
In the fight against cancer, controlled drug delivery systems have emerged to enhance the therapeutic efficacy and safety of anti-cancer drugs. Among these systems, mesoporous silica nanoparticles (MSNs) with a func...In the fight against cancer, controlled drug delivery systems have emerged to enhance the therapeutic efficacy and safety of anti-cancer drugs. Among these systems, mesoporous silica nanoparticles (MSNs) with a functional surface possess obvious advantages and were thus rapidly developed for cancer treatment. Many stimuli-responsive materials, such as nanopartides, polymers, and inorganic materials, have been applied as caps and gatekeepers to control drug release from MSNs. This review presents an overview of the recent progress in the production of pH-responsive MSNs based on the pH gradient between normal tissues and the tumor microenvironment. Four main categories of gatekeepers can respond to acidic conditions. These categories will be described in detail.展开更多
In an effort to reduce thermal shrinkage and improve electrochemical performance of porous polypropylene (PP) separators for lithium-ion batteries, a new composite separator is developed by introducing ceramic coate...In an effort to reduce thermal shrinkage and improve electrochemical performance of porous polypropylene (PP) separators for lithium-ion batteries, a new composite separator is developed by introducing ceramic coated layers on both sides of PP separator through a dip-coating process. The coated layers are comprised of heat-resistant and hydrophilic silica nanoparticles and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) binders. Highly porous honeycomb structure is formed and the thickness of the layer is only about 700 nm. In comparison to the pristine PP separator, the composite separator shows significant reduction in thermal shrinkage and improvement in liquid electrolyte uptake and ionic conduction, which play an important role in improving cell performance such as discharge capacity, C-rate capability, cycle performance and coulombic efficiency.展开更多
[Objective] This study aimed to develop a method of C_18-functionalized magnetic silica nanoparticles solid phase extraction-high performance liquid chro- matography-tandem mass spectrometry for the determination of s...[Objective] This study aimed to develop a method of C_18-functionalized magnetic silica nanoparticles solid phase extraction-high performance liquid chro- matography-tandem mass spectrometry for the determination of sulfadimidine in royal jelly. [Method] The royal jelly samples were pretreated by MCX SPE column and C_18-functionalized magnetic silica nanoparticles, and the purified samples were de- tected by HPLC-MS/MS. [Result] The detection method showed a good linear rela- tionship in the range of 5-80 ugkg (r=0.993 1). The recovery ranges were between 93%- 104% with the relative standard deviations (RSD) below 11.3%. [Conclusion] Combined with automation equipment, the method is simple, fast, time-saving, and easy to real- ize the automation of sulfadimidine in the royal jelly samples before determination.展开更多
Recently,nanoparticles have proven to enhance oil recovery on the core-flood scale in challenging high-pressure high-temperature reservoirs.Nanomaterials generally appear to improve oil production through wettability ...Recently,nanoparticles have proven to enhance oil recovery on the core-flood scale in challenging high-pressure high-temperature reservoirs.Nanomaterials generally appear to improve oil production through wettability alteration and reduction in interfacial tension between oil and water phases.Besides,they are environmentally friendly and cost-effective enhanced oil recovery techniques.Studying the rheological properties of nanoparticles is critical for field applications.The instability of nanoparticle dispersion due to aggregation is considered as an unfavorable phenomenon in nanofluid flooding while conducting an EOR process.In this study,wettability behavior and rheological properties of surface-treated silica nanoparticles using internal olefins sulfonates(IOS20–24 and IOS19–23),anionic surfactants were investigated.Surface modification effect on the stability of the colloidal solution in porous media and oil recovery was inspected.The rheology of pure and surfacetreated silica nanoparticles was investigated using a HPHT rheometer.Morphology and particle size distributions of pure and coated silica nanoparticles were studied using a field emission scanning electron microscope.A series of core-flood runs was conducted to evaluate the oil recovery factor.The coated silica nanoparticles were found to alter rheological properties and exhibited a shear-thinning behavior as the stability of the coated silica nanoparticles could be improved considerably.At low shear rates,the viscosity slightly increases,and the opposite happens at higher shear rates.Furthermore,the surfacemodified silica nanoparticles were found to alter the wettability of the aqueous phase into strongly water-wet by changing the contact angle from 80°to 3°measured against glass slides representing sandstone rocks.Oil–water IFT results showed that the surface treatment by surfactant lowered the oil–water IFT by 30%.Also,the viscosity of brine increased from 0.001 to 0.008 Pa s by introducing SiO2 nanoparticles to the aqueous phase for better displacement efficiency during chemicalassisted EOR.The core-flood experiments revealed that the ultimate oil recovery is increased by approximately 13%with a surfactant-coated silica nanofluid flood after the conventional waterflooding that proves the potential of smart nanofluids for enhancing oil recovery.The experimental results imply that the use of surfactant-coated nanoparticles in tertiary oil recovery could facilitate the displacement efficiency,alter the wettability toward more water-wet and avoid viscous fingering for stable flood front and additional oil recovery.展开更多
Gene therapy using siRNA molecules is nowadays considered as a promising approach. For successful therapy, development of a stable and reliable vector for siRNA is crucial. Non-viral and non-organic vectors like mesop...Gene therapy using siRNA molecules is nowadays considered as a promising approach. For successful therapy, development of a stable and reliable vector for siRNA is crucial. Non-viral and non-organic vectors like mesoporous silica nanoparticles(MSN) are associated with lack of most viral vector drawbacks, such as toxicity, immunogenicity, but also generally a low nucleic acid carrying capacity. To overcome this hurdle, we here modified the pore walls of MSNs with surface-hyperbranching polymerized poly(ethyleneimine)(hbPEI), which provides an abundance of amino-groups for loading of a larger amount of siRNA molecules via electrostatic adsorption. After loading, the particles were covered with a second layer of pre-polymerized PEI to provide better protection of siRNA inside the pores, more effective cellular uptake and endosomal escape. To test the transfection efficiency of PEI covered si RNA/MSNs, MDA-MB 231 breast cancer cells stably expressing GFP were used. We demonstrate that PEI-coated si RNA/MSN complexes provide more effective delivery of si RNAs compared to unmodified MSNs. Thus, it can be concluded that appropriately surface-modified MSNs can be considered as prospective vectors for therapeutic siRNA delivery.展开更多
Objective To investigate the subchronic oral toxicity of silica nanoparticles(NPs) and silica microparticles(MPs) in rats and to compare the difference in toxicity between two particle sizes.Methods Sprague-Dawley...Objective To investigate the subchronic oral toxicity of silica nanoparticles(NPs) and silica microparticles(MPs) in rats and to compare the difference in toxicity between two particle sizes.Methods Sprague-Dawley rats were randomly divided into seven groups: the control group; the silica NPs low-, middle-, and high-dose groups; and the silica MPs low-, middle-, and high-dose groups [166.7,500, and 1,500 mg/(kg·bw·day)]. All rats were gavaged daily for 90 days, and deionized water was administered to the control group. Clinical observations were made daily, and body weights and food consumption were determined weekly. Blood samples were collected on day 91 for measurement of hematology and clinical biochemistry. Animals were euthanized for necropsy, and selected organs were weighed and fixed for histological examination. The tissue distribution of silicon in the blood, liver,kidneys, and testis were determined.Results There were no toxicologically significant changes in mortality, clinical signs, body weight,food consumption, necropsy findings, and organ weights. Differences between the silica groups and the control group in some hematological and clinical biochemical values and histopathological findings were not considered treatment related. The tissue distribution of silicon was comparable across all groups.Conclusion Our study demonstrated that neither silica NPs nor silica MPs induced toxicological effects after subchronic oral exposure in rats.展开更多
A light and temperature dual responsive copolymer,poly(7-(4-vinylbenzy-loxyl)-4-methylcoumarin-co-N vinyl caprolactam-co-tri(ethylene glycol)methyl ether methacrylate)(PVNM),was grafted on the surface of dopamine base...A light and temperature dual responsive copolymer,poly(7-(4-vinylbenzy-loxyl)-4-methylcoumarin-co-N vinyl caprolactam-co-tri(ethylene glycol)methyl ether methacrylate)(PVNM),was grafted on the surface of dopamine based mesoporous silica nanoparticles(MSNs).The resulting polymer brush,MSNs-g-PVNM,was characterized by FT-IR,TEM,TGA and XPS.The dual responsive behaviors of MSNs-g-PVNM were systematically studied.With imidacloprid as the model guest pesticide,the loading percentage and loading efficiency of the polymer brush were determined as 9.2%and 40.6%,respectively.The release efficiency of imidacloprid in MSNs-g-PVNM was the lowest value of 5.4%at 20℃ and 365 nm,and it reached the highest value of 52.4%at 50℃ and 254 nm.The loss percentage of imidacloprid on the leaves contained imidacloprid-loaded MSNs-g-PVNM(8.4%)was much less than that contained only imidacloprid(25.2%)after three rinses.It was confirmed that the release process of imidacloprid was well regulated through changing external conditions such as light and temperature.展开更多
Nitric oxide(NO)has been shown to promote revascularization and nerve regeneration after peripheral nerve injury.However,in vivo application of NO remains challenging due to the lack of stable carrier materials capabl...Nitric oxide(NO)has been shown to promote revascularization and nerve regeneration after peripheral nerve injury.However,in vivo application of NO remains challenging due to the lack of stable carrier materials capable of storing large amounts of NO molecules and releasing them on a clinically meaningful time scale.Recently,a silica nanoparticle system capable of reversible NO storage and release at a controlled and sustained rate was introduced.In this study,NO-releasing silica nanoparticles(NO-SNs)were delivered to the peripheral nerves in rats after acute crush injury,mixed with natural hydrogel,to ensure the effective application of NO to the lesion.Microangiography using a polymer dye and immunohistochemical staining for the detection of CD34(a marker for revascularization)results showed that NO-releasing silica nanoparticles increased revascularization at the crush site of the sciatic nerve.The sciatic functional index revealed that there was a significant improvement in sciatic nerve function in NO-treated animals.Histological and anatomical analyses showed that the number of myelinated axons in the crushed sciatic nerve and wet muscle weight excised from NO-treated rats were increased.Moreover,muscle function recovery was improved in rats treated with NO-SNs.Taken together,our results suggest that NO delivered to the injured sciatic nerve triggers enhanced revascularization at the lesion in the early phase after crushing injury,thereby promoting axonal regeneration and improving functional recovery.展开更多
This work is focused on immobilization of laccase from Myceliophthora thermophila expressed in Aspergillus oryzae(Novozym 51003?laccase)on amino modified fumed nano-silica(AFNS)and the possible use in bioremediation.H...This work is focused on immobilization of laccase from Myceliophthora thermophila expressed in Aspergillus oryzae(Novozym 51003?laccase)on amino modified fumed nano-silica(AFNS)and the possible use in bioremediation.Hereby,for the first time,factors affecting the immobilization of Novozym 51003?laccase on AFNS were investigated for defining the immobilization mechanism and optimizing the utilization of AFNS as support for laccase immobilization.The highest specific activity(13.1 IU·mg-1 proteins)was achieved at offered 160 mg per g of AFNS and for the same offered protein concentration the highest activity immobilization yield,reaching68.3%after the equilibrium time,at optimum pH 5.0,was obtained.Laccase immobilization occurs by adsorption as monolayer enzyme binding in 40 min,following pseudo-first-order kinetics.The possible use of obtained immobilized preparation was investigated in degradation of pesticide lindane.Within 24 h,lindane concentration was reduced to 56.8%of initial concentration and after seven repeated reuses it retained 70%of the original activity.展开更多
A self-regulated anti-diabetic drug release device mimicking pancreatic cells is highly desirable for the therapy of diabetes. Herein, a glucose-mediated dual-responsive drug delivery system, which combines pH-and H_(...A self-regulated anti-diabetic drug release device mimicking pancreatic cells is highly desirable for the therapy of diabetes. Herein, a glucose-mediated dual-responsive drug delivery system, which combines pH-and H_(2)O_(2)-responsive block copolymer grafted hollow mesoporous silica nanoparticles(HMSNs)with microneedle(MN) array patch, has been developed to achieve self-regulated administration.The poly[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl acrylate]-b-poly[2-(dimethylamino)ethyl methacrylate](PPBEM-b-PDM) polymer serves as gate keeper to prevent drug release from the cavity of HMSNs at normoglycemic level. In contrast, the drug release rate is significantly enhanced upon H_(2)O_(2)and pH stimuli due to the chemical change of H_(2)O_(2)sensitive PPBEM block and acid responsive PDM block. Therefore, incorporation of anti-diabetic drug and glucose oxidase(GOx, which can oxidize glucose to gluconic acid and in-situ produce H_(2)O_(2)) into stimulus polymer coated HMSNs results in a glucose-mediated MN device after depositing the drug-loaded nanoparticles into MN array patch. Both in vitro and in vivo results show this MN device presents a glucose mediated self-regulated drug release characteristic, which possesses a rapid drug release at hyperglycemic level but retarded drug release at normoglycemic level. The result indicates that the fabricated smart drug delivery system is a good candidate for the therapy of diabetes.展开更多
Among the several types of inorganic nanoparticles available,silica nanoparticles(SNP)have earned their relevance in biological applications namely,as bioimaging agents.In fact,uorescent SNP(FSNP)have been explored in...Among the several types of inorganic nanoparticles available,silica nanoparticles(SNP)have earned their relevance in biological applications namely,as bioimaging agents.In fact,uorescent SNP(FSNP)have been explored in this-eld as protective nanocarriers,overcoming some limitations presented by conventional organic dyes such as high photobleaching rates.A crucial aspect on the use of uorescent SNP relates to their surface properties,since it determines the extent of interaction between nanoparticles and biological systems,namely in terms of colloidal stability in water,cellular recognition and internalization,tracking,biodistribution and speci-city,among others.Therefore,it is imperative to understand the mechanisms underlying the interaction between biosystems and the SNP surfaces,making surface functionalization a relevant step in order to take full advantage of particle properties.The versatility of the surface chemistry on silica platforms,together with the intrinsic hydrophilicity and biocompatibility,make these systems suitable for bioimaging applications,such as those mentioned in this review.展开更多
Controlled release of the functional factors is the key to improve clinical therapeutic efficacy during the tissue repair and regeneration. The thrce-dimensional (3D) scaffold can provide not only physical propertie...Controlled release of the functional factors is the key to improve clinical therapeutic efficacy during the tissue repair and regeneration. The thrce-dimensional (3D) scaffold can provide not only physical properties such as high strength and porosity hut also an optimal environment to enhance tissue regeneration. Sphingosine 1-phosphate (SIP), an angiogenlc factor, was loaded into mesoporous silica nanoparticles (MSNs) and then incorporated into poly ( L-lactic add ) ( PLLA ) nanofibrons scaffold, which was fabricated by thermally induced phase separation (TIPS) method. The prepared scaffolds were examined by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy ( SEM), and transmission electron microscopy (TEM) and compressive mechanical test. The ATR-FTIR result demonstrated the existence of MSNs in the PLLA nanofibrous scaffold. The SEM images showed that PLLA scaffold had regular pore channel, interconnected pores and nanofibrous structure. The addition of MSNs at appropriate content had no visible effect on the structure of scaffold. The compressive modulus of scaffold containing MSNs was higher than that of the scaffold without MSNs. Furthermore, fluorescein isothiocyanate (FTTC) was used as model molecule to investigate the release behavior of SIP from MSNs- incorporated PLLA (MSNs/PLLA) nanofibrons scaffold. The result showed that the composite scaffold largely reduced the initial burst release and exhibited prolonged release of FITC than MSNs. Thus, these results indicated that SIP-loaded composite uanofibrons scaffold has potential applications for bone tissue engneering.展开更多
A rapid, precise, sensitive and simple method has been developed for the extraction and determination of TPT (triphenyltin), DPT (diphenyltin) and MPT (monophenyltin) in seawater samples. The procedure is based ...A rapid, precise, sensitive and simple method has been developed for the extraction and determination of TPT (triphenyltin), DPT (diphenyltin) and MPT (monophenyltin) in seawater samples. The procedure is based on the use of the dual functionalization of mesoporous silica with diol and Cl6 alkane groups for the collection of TPT and its derivatives, DPT and MPT, from seawater samples, followed by ethylation of the target matrices using sodium tetraethylborate (NaBEt4) and quantification by gas chromatography with pulsed flame photometric detection. The modified extraction method replaces conventional solid- and liquid-phase extraction with solid dispersion of silica nanoparticles. The partitioning of the analyte between a carefully size-selected silica nanoparticles (solid phase) and a liquid phase occurs as the solid moves through the sample as a colloidal sol. By tailoring the size of the particles to approximately 250 nm in diameter, they can be easily dispersed in aqueous solution, without the need for any mechanical or hand shaking and the solid can then be readily recovered, together with the analytes, by simple filtration or centrifugation. Recoveries of TPT, DPT and MPT chloride spiked matrices rang from 87.3±1.1 to 98.1±1.3 in seawater samples (n = I 1 samples). The limit of detection obtained was typically in the range of 0.1-3 ng Sn/L. The proposed method shows excellent linearity in the range of 0.5-2 ng Sn/L and good repeatability (RSD 〈 5% at 0.02 ng TPT (as Sn)/L). The method performance is demonstrated with real seawater samples.展开更多
Colloidal mesoporous silica nanoparticles functionalized with carboxy-terminated polyethylene glycol(CMS-PEG-COOH) were successfully synthesized by covalently grafting dicarboxy-terminated polyethylene glycol(HOOC-PEG...Colloidal mesoporous silica nanoparticles functionalized with carboxy-terminated polyethylene glycol(CMS-PEG-COOH) were successfully synthesized by covalently grafting dicarboxy-terminated polyethylene glycol(HOOC-PEG-COOH) on the surface of the amino functionalized CMS nanoparticles with amide bond as a cross linker. Moreover, the structural and particle properties of CMS-PEG-COOH were characterized by nuclear magnetic resonance spectroscopy(1 H-NMR), transmission electron microscopy(TEM), dynamic light scattering(DLS), nitrogen adsorption-desorption measurements, X-ray diffraction(XRD), and Fourier transform infrared spectroscopy(FT-IR). The nanomaterials presented a relatively uniform spherical shape morphology with diameters of about 120 nm,and favorable dispersibility in weak acid solution. The CMSPEG-COOH exhibited no changes in the state of amorphous, while the mesopores sizes of 5.25 nm might provide the nanomaterials with large capacity for the loading and releasing of drugs. So the results indicated that CMSPEG-COOH might be a critical nanomaterial for drug delivery system in the future.展开更多
Enhanced oil recovery(EOR)processes are applied to recover trapped or residual oil in the reservoir rocks after primary and secondary recovery methods.Changing the wettability of the rock from oil-wet to water-wet is ...Enhanced oil recovery(EOR)processes are applied to recover trapped or residual oil in the reservoir rocks after primary and secondary recovery methods.Changing the wettability of the rock from oil-wet to water-wet is named wettability alteration.It is an important factor for EOR.Due to their unique properties,nanoparticles have gained great attention for improving oil recovery.Despite the promising results,the main challenges of applying nanoparticles are related to the colloidal stability of the nanofuids in the harsh conditions of the reservoirs.In recent years,polymer-grafted nanoparticles have been considered as novel promising materials for EOR.The obtained results showed that adding a hydrophobic agent trimethoxy(propyl)silane on the surface of modifed silica nanoparticles with polyethylene glycol methyl ether has an efective role in improving retention and wettability alteration,especially in the oil-wet substrate due to hydrophobic interaction.The modifed silica nanoparticle by mixed polyethylene glycol methyl ether(Mn~5000)and trimethoxy(propyl)silane showed a proper performance at a concentration of 1000 ppm and a salinity range of 2000-40,000 ppm.The obtained fndings can help for a better understanding of the silica nanofuid modifcation with both hydrophilic and hydrophobic agents for the EOR application of near-wellbore.展开更多
In petroleum industry, crude oil emulsions are commonly formed in oilfields. The asphaltenes and fine particles in crude oil may affect the stability of the emulsions by adsorbing at the water/oil interface. In this r...In petroleum industry, crude oil emulsions are commonly formed in oilfields. The asphaltenes and fine particles in crude oil may affect the stability of the emulsions by adsorbing at the water/oil interface. In this research, the effect of silica nanoparticles and asphaltenes on emulsion stability is explored first. The asphaltenes are proved to benefit emulsion stability. Unlike the asphaltenes, however, the modified silica nanoparticles may have positive or negative effect on emulsion stability, depending on the asphaltene concentration and aggregation degree in the emulsions. Further, it is confirmed by conducting interfacial experiment that the asphaltenes and particles can adsorb at the interface simultaneously and determine the properties of the interfacial layer. More in-depth experiments concerning contact angle and asphaltene adsorption amount on the particles indicate that the asphaltenes can modify the wettability of the particles. Higher concentration and lower aggregation degree of the asphaltenes can increase their adsorption amount on the surface of particles and then improve the modification effectiveness of the particles. Resultantly, the particles with good modification effectiveness can enhance the emulsion stability while the particles with poor modification effectiveness will weaken the emulsion stability.展开更多
The effect of silica nanoparticles on the rheological characteristics of water-in-heavy oil emulsions has been investigated.Enhanced oil recovery methods for heavy oil production(most especially,thermal fluid injectio...The effect of silica nanoparticles on the rheological characteristics of water-in-heavy oil emulsions has been investigated.Enhanced oil recovery methods for heavy oil production(most especially,thermal fluid injection)usually result in the formation of water-in-oil(W/O)emulsion.In reality,the emulsion produced also contains some fine solid mineral particles such as silica,which,depending on its quantity,may alter the viscosity and/or rheological properties of the fluid.A series of binary-component emulsions were separately prepared by dispersing silica nanoparticles[phase fraction,βs,=0.5%–5.75%(wt/v)]in heavy oil(S/O suspension)and by dispersing water[water cut,θw=10%–53%(v/v)]in heavy oil(W/O emulsion).Ternary-component emulsions comprising heavy oil,water droplets and suspended silica nanoparticles(S/W/O)were also prepared with similar ranges ofθw andβs.The viscosity was measured at different shear rates(5.1–1021.4 s-1)and temperatures(30–70°C).Both binary-component and ternary-component emulsion systems were observed to exhibit nonNewtonian shear thinning behaviour.The viscosity of the heavy oil and W/O emulsions increased in the presence of silica nanoparticles.The effect was,however,less signifi cant belowβs=2%(wt/v).Moreover,a generalized correlation has been proposed to predict the viscosity of both binary-component and ternary-component emulsions.展开更多
Due to the amphiphilic nature of phospholipids in the cell membrane,the amphipathicity of the nanomedicine plays a crucial role in the endocytosis.However,limited biological characterization methods restrict the study...Due to the amphiphilic nature of phospholipids in the cell membrane,the amphipathicity of the nanomedicine plays a crucial role in the endocytosis.However,limited biological characterization methods restrict the study of the state of nanoparticles with different amphiphilicities on cell membranes.The understanding of interaction of amphiphilic particle with cell membrane is still lacking.Herein,by combining the dissipative particle dynamics(DPD)with the framework construction of mesoporous silica nanoparticles(MSNs),we demonstrate the enhanced endocytosis induced by the hydrophobicity.DPD results confirm that the presence of hydrophobic groups on the surface of nanoparticles can disturb the integrity of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine(POPC)membrane and induce activation of phospholipids to a higher energy level,thereby facilitating the wrapping of nanoparticles.To validate the simulation findings,uniform MSNs with hydrophilic pure silica framework and two types of amphiphilic MSNs with varying hydrophilic organic groups in the framework are rationally synthesized by using different silane precursors.The obtained three kinds of MSNs show similar diameter(~100 nm)and mesopores(~2 nm),but distinct hydrophobicity/hydrophilicity ratio.The phenyl-bridged MSN with a carbon content of 27.1%exhibits enhanced cellular uptake,consistent with the theoretical simulation results.This work sheds light on how the surface amphipathicity influences endocytosis through the interaction with cell membrane.展开更多
Conductive hydrogels have garnered considerable interest for their applications in wearable electronic skins,owing to their superior properties.Nevertheless,challenges persist,including low sensitivity,poor cyclic sta...Conductive hydrogels have garnered considerable interest for their applications in wearable electronic skins,owing to their superior properties.Nevertheless,challenges persist,including low sensitivity,poor cyclic stability,and limited tolerance to extreme conditions.This study develops a novel liquid metal-based conductive hydrogel with a dual cross-linked polyacrylic acid(PAA)matrix,employing both“soft”coordination and“hard”covalent cross-linking mechanisms.This hybrid network is formulated using guar gum(GG)-stabilized gallium(Ga)droplets,which catalyze the copolymerization of vinyl-hybrid silica nanoparticles(VSNPs)and acrylic acid(AA).The resultant Ga3+ions interact with carboxyl groups in the PAA,forming soft coordination links that enhance the hydrogel’s rapid gelation.The incorporation of VSNPs significantly enhances the hydrogel’s elasticity,toughness,and low-temperature resilience without glycerol.Notably,its intrinsic moldability,adhesion,and self-healing properties are retained.Applied as a strain sensor,this hydrogel demonstrates a high gauge factor(GF)of 17.4,responsive time of 250 ms for both activation and recovery,an ultra-low detection limit of 0.1%,and excellent durability over 800 cycles at 100%strain.Short-term immersion in a glycerol solution(20 min)further augments its stretchability to 2688%and GF to 28.1 across a strain range of 1325%–1450%,broadening its operational ranges to 0–1450%at−18°C.Prolonged exposure(4 h)also improves water retention and high-temperature resistance,making this hydrogel a promising material for sustainable,high-performance wearable electronics.展开更多
基金supported by the National Key Technologies R&D Programs of China (No.2006BAI19B05,2006BAJ02A10)
文摘To assess the aquatic ecosystem safety for silica (SiO2) nanoparticles (NPs), the growth inhibition and photosynthetic pigment contents of Scenedesmus obliquus in logarithm growth phase exposed to SiO2 NPs and SiO2 bulk particles (BPs) suspensions were measured. SiO2 NPs with 10-20 nm diameters were found to be toxic. The 20% effective concentration (EC20) values for 72 and 96 hr were 388.1 and 216.5 mg/L, respectively. The contents of chlorophyll decreased significantly under moderate and high concentration (50, 100, and 200 mg/L) of SiO2 NPs after 96-hr exposure, but the carotenoids did not. SiO2 BPs were found to be nontoxic up to 200 mg/L. The toxicity of SiO2 NPs probablely due to their sorption to algal cells surface. The results imply that there is potential harm to aquatic environment by using SiO2 NPs, and it should deserve special concern.
基金supported by the Chinese Natural Science Foundation Project (Grant No. 30970784 and 81171455)a National Distinguished Young Scholars Grant (Grant No. 31225009) from the National Natural Science Foundation of China+5 种基金the National Key Basic Research Program of China (Grant No. 2009CB930200)the Chinese Academy of Sciences (CAS) ‘Hundred Talents Program’ (Grant No. 07165111ZX)the CAS Knowledge Innovation Program, and the State HighTech Development Plan (Grant No. 2012AA020804)the ‘Strategic Priority Research Program’ of the Chinese Academy of Sciences (Grant No. XDA09030301)NIH/NIMHD 8 G12 MD007597USAMRMC W81XWH-10-1-0767 grants
文摘In the fight against cancer, controlled drug delivery systems have emerged to enhance the therapeutic efficacy and safety of anti-cancer drugs. Among these systems, mesoporous silica nanoparticles (MSNs) with a functional surface possess obvious advantages and were thus rapidly developed for cancer treatment. Many stimuli-responsive materials, such as nanopartides, polymers, and inorganic materials, have been applied as caps and gatekeepers to control drug release from MSNs. This review presents an overview of the recent progress in the production of pH-responsive MSNs based on the pH gradient between normal tissues and the tumor microenvironment. Four main categories of gatekeepers can respond to acidic conditions. These categories will be described in detail.
基金supported by the Tsinghua University Initiative Scientific Research Program(Grant No.2012THZ08129)
文摘In an effort to reduce thermal shrinkage and improve electrochemical performance of porous polypropylene (PP) separators for lithium-ion batteries, a new composite separator is developed by introducing ceramic coated layers on both sides of PP separator through a dip-coating process. The coated layers are comprised of heat-resistant and hydrophilic silica nanoparticles and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) binders. Highly porous honeycomb structure is formed and the thickness of the layer is only about 700 nm. In comparison to the pristine PP separator, the composite separator shows significant reduction in thermal shrinkage and improvement in liquid electrolyte uptake and ionic conduction, which play an important role in improving cell performance such as discharge capacity, C-rate capability, cycle performance and coulombic efficiency.
基金Supported by the Innovation Fund for Technology Based Firms of Ministry of Science and Technology(09C26214425280)the National Key Technology R&D Program during the 12th Five-Year Plan Period(2012BAK17B10)the International S&T Cooperation and Communication Program of China(2011DFA32930)~~
文摘[Objective] This study aimed to develop a method of C_18-functionalized magnetic silica nanoparticles solid phase extraction-high performance liquid chro- matography-tandem mass spectrometry for the determination of sulfadimidine in royal jelly. [Method] The royal jelly samples were pretreated by MCX SPE column and C_18-functionalized magnetic silica nanoparticles, and the purified samples were de- tected by HPLC-MS/MS. [Result] The detection method showed a good linear rela- tionship in the range of 5-80 ugkg (r=0.993 1). The recovery ranges were between 93%- 104% with the relative standard deviations (RSD) below 11.3%. [Conclusion] Combined with automation equipment, the method is simple, fast, time-saving, and easy to real- ize the automation of sulfadimidine in the royal jelly samples before determination.
文摘Recently,nanoparticles have proven to enhance oil recovery on the core-flood scale in challenging high-pressure high-temperature reservoirs.Nanomaterials generally appear to improve oil production through wettability alteration and reduction in interfacial tension between oil and water phases.Besides,they are environmentally friendly and cost-effective enhanced oil recovery techniques.Studying the rheological properties of nanoparticles is critical for field applications.The instability of nanoparticle dispersion due to aggregation is considered as an unfavorable phenomenon in nanofluid flooding while conducting an EOR process.In this study,wettability behavior and rheological properties of surface-treated silica nanoparticles using internal olefins sulfonates(IOS20–24 and IOS19–23),anionic surfactants were investigated.Surface modification effect on the stability of the colloidal solution in porous media and oil recovery was inspected.The rheology of pure and surfacetreated silica nanoparticles was investigated using a HPHT rheometer.Morphology and particle size distributions of pure and coated silica nanoparticles were studied using a field emission scanning electron microscope.A series of core-flood runs was conducted to evaluate the oil recovery factor.The coated silica nanoparticles were found to alter rheological properties and exhibited a shear-thinning behavior as the stability of the coated silica nanoparticles could be improved considerably.At low shear rates,the viscosity slightly increases,and the opposite happens at higher shear rates.Furthermore,the surfacemodified silica nanoparticles were found to alter the wettability of the aqueous phase into strongly water-wet by changing the contact angle from 80°to 3°measured against glass slides representing sandstone rocks.Oil–water IFT results showed that the surface treatment by surfactant lowered the oil–water IFT by 30%.Also,the viscosity of brine increased from 0.001 to 0.008 Pa s by introducing SiO2 nanoparticles to the aqueous phase for better displacement efficiency during chemicalassisted EOR.The core-flood experiments revealed that the ultimate oil recovery is increased by approximately 13%with a surfactant-coated silica nanofluid flood after the conventional waterflooding that proves the potential of smart nanofluids for enhancing oil recovery.The experimental results imply that the use of surfactant-coated nanoparticles in tertiary oil recovery could facilitate the displacement efficiency,alter the wettability toward more water-wet and avoid viscous fingering for stable flood front and additional oil recovery.
基金supported in part by Russian Science Founda-tion grant 17-15-01230(biological characterization)Academy of Finland project nos.284542,384542(JMR)+2 种基金Jane and Aatos Erkko Foundation(EC)Anna Egorova is supported by President of Russian Federation scholarship(SP-2162.2015.4)Anna Slita was supported by the scholarship within Saint Pe-tersburg State University bilateral exchange program for study abroad
文摘Gene therapy using siRNA molecules is nowadays considered as a promising approach. For successful therapy, development of a stable and reliable vector for siRNA is crucial. Non-viral and non-organic vectors like mesoporous silica nanoparticles(MSN) are associated with lack of most viral vector drawbacks, such as toxicity, immunogenicity, but also generally a low nucleic acid carrying capacity. To overcome this hurdle, we here modified the pore walls of MSNs with surface-hyperbranching polymerized poly(ethyleneimine)(hbPEI), which provides an abundance of amino-groups for loading of a larger amount of siRNA molecules via electrostatic adsorption. After loading, the particles were covered with a second layer of pre-polymerized PEI to provide better protection of siRNA inside the pores, more effective cellular uptake and endosomal escape. To test the transfection efficiency of PEI covered si RNA/MSNs, MDA-MB 231 breast cancer cells stably expressing GFP were used. We demonstrate that PEI-coated si RNA/MSN complexes provide more effective delivery of si RNAs compared to unmodified MSNs. Thus, it can be concluded that appropriately surface-modified MSNs can be considered as prospective vectors for therapeutic siRNA delivery.
基金supported by China Food Safety Talent Competency Development Initiative:CFSA 523 Program
文摘Objective To investigate the subchronic oral toxicity of silica nanoparticles(NPs) and silica microparticles(MPs) in rats and to compare the difference in toxicity between two particle sizes.Methods Sprague-Dawley rats were randomly divided into seven groups: the control group; the silica NPs low-, middle-, and high-dose groups; and the silica MPs low-, middle-, and high-dose groups [166.7,500, and 1,500 mg/(kg·bw·day)]. All rats were gavaged daily for 90 days, and deionized water was administered to the control group. Clinical observations were made daily, and body weights and food consumption were determined weekly. Blood samples were collected on day 91 for measurement of hematology and clinical biochemistry. Animals were euthanized for necropsy, and selected organs were weighed and fixed for histological examination. The tissue distribution of silicon in the blood, liver,kidneys, and testis were determined.Results There were no toxicologically significant changes in mortality, clinical signs, body weight,food consumption, necropsy findings, and organ weights. Differences between the silica groups and the control group in some hematological and clinical biochemical values and histopathological findings were not considered treatment related. The tissue distribution of silicon was comparable across all groups.Conclusion Our study demonstrated that neither silica NPs nor silica MPs induced toxicological effects after subchronic oral exposure in rats.
基金Project(21376271)supported by the National Natural Science Foundation of ChinaProject(2016TP1007)supported by the Hunan Provincial Science and Technology Plan Project,ChinaProjects(201810533078,S2020105330395)supported by the Undergraduates Innovative Training Foundation of Central South University,China。
文摘A light and temperature dual responsive copolymer,poly(7-(4-vinylbenzy-loxyl)-4-methylcoumarin-co-N vinyl caprolactam-co-tri(ethylene glycol)methyl ether methacrylate)(PVNM),was grafted on the surface of dopamine based mesoporous silica nanoparticles(MSNs).The resulting polymer brush,MSNs-g-PVNM,was characterized by FT-IR,TEM,TGA and XPS.The dual responsive behaviors of MSNs-g-PVNM were systematically studied.With imidacloprid as the model guest pesticide,the loading percentage and loading efficiency of the polymer brush were determined as 9.2%and 40.6%,respectively.The release efficiency of imidacloprid in MSNs-g-PVNM was the lowest value of 5.4%at 20℃ and 365 nm,and it reached the highest value of 52.4%at 50℃ and 254 nm.The loss percentage of imidacloprid on the leaves contained imidacloprid-loaded MSNs-g-PVNM(8.4%)was much less than that contained only imidacloprid(25.2%)after three rinses.It was confirmed that the release process of imidacloprid was well regulated through changing external conditions such as light and temperature.
基金supported by the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT,Nos.NRF-2015R1C1A1A02036830(to JIL)and NRF-2015M3A9E2029186(to JHS)+1 种基金supported by a grant of the Korea Institute of Science and Technology,Nos.2V05460/2V08630(KIST-KU TRC program),2E31121(to MRO)a grant of Korea University Anam Hospital(to JHP and JWP).
文摘Nitric oxide(NO)has been shown to promote revascularization and nerve regeneration after peripheral nerve injury.However,in vivo application of NO remains challenging due to the lack of stable carrier materials capable of storing large amounts of NO molecules and releasing them on a clinically meaningful time scale.Recently,a silica nanoparticle system capable of reversible NO storage and release at a controlled and sustained rate was introduced.In this study,NO-releasing silica nanoparticles(NO-SNs)were delivered to the peripheral nerves in rats after acute crush injury,mixed with natural hydrogel,to ensure the effective application of NO to the lesion.Microangiography using a polymer dye and immunohistochemical staining for the detection of CD34(a marker for revascularization)results showed that NO-releasing silica nanoparticles increased revascularization at the crush site of the sciatic nerve.The sciatic functional index revealed that there was a significant improvement in sciatic nerve function in NO-treated animals.Histological and anatomical analyses showed that the number of myelinated axons in the crushed sciatic nerve and wet muscle weight excised from NO-treated rats were increased.Moreover,muscle function recovery was improved in rats treated with NO-SNs.Taken together,our results suggest that NO delivered to the injured sciatic nerve triggers enhanced revascularization at the lesion in the early phase after crushing injury,thereby promoting axonal regeneration and improving functional recovery.
基金the Ministry of Education,Science and Technological Development,Republic of Serbia,within projectsⅢ46010,Ⅲ45019 and TR31035 for the financialDirectorate of Measures and Precious Metals,Ministry of Economy,Republic of Serbia for the technical support。
文摘This work is focused on immobilization of laccase from Myceliophthora thermophila expressed in Aspergillus oryzae(Novozym 51003?laccase)on amino modified fumed nano-silica(AFNS)and the possible use in bioremediation.Hereby,for the first time,factors affecting the immobilization of Novozym 51003?laccase on AFNS were investigated for defining the immobilization mechanism and optimizing the utilization of AFNS as support for laccase immobilization.The highest specific activity(13.1 IU·mg-1 proteins)was achieved at offered 160 mg per g of AFNS and for the same offered protein concentration the highest activity immobilization yield,reaching68.3%after the equilibrium time,at optimum pH 5.0,was obtained.Laccase immobilization occurs by adsorption as monolayer enzyme binding in 40 min,following pseudo-first-order kinetics.The possible use of obtained immobilized preparation was investigated in degradation of pesticide lindane.Within 24 h,lindane concentration was reduced to 56.8%of initial concentration and after seven repeated reuses it retained 70%of the original activity.
基金financially supported by the Zhejiang Provincial Natural Science Foundation of China (LY20E030005)Natural Science Foundation of Zhejiang Education Department (Y201942793)the Opening Project of Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices (PMND201905)。
文摘A self-regulated anti-diabetic drug release device mimicking pancreatic cells is highly desirable for the therapy of diabetes. Herein, a glucose-mediated dual-responsive drug delivery system, which combines pH-and H_(2)O_(2)-responsive block copolymer grafted hollow mesoporous silica nanoparticles(HMSNs)with microneedle(MN) array patch, has been developed to achieve self-regulated administration.The poly[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl acrylate]-b-poly[2-(dimethylamino)ethyl methacrylate](PPBEM-b-PDM) polymer serves as gate keeper to prevent drug release from the cavity of HMSNs at normoglycemic level. In contrast, the drug release rate is significantly enhanced upon H_(2)O_(2)and pH stimuli due to the chemical change of H_(2)O_(2)sensitive PPBEM block and acid responsive PDM block. Therefore, incorporation of anti-diabetic drug and glucose oxidase(GOx, which can oxidize glucose to gluconic acid and in-situ produce H_(2)O_(2)) into stimulus polymer coated HMSNs results in a glucose-mediated MN device after depositing the drug-loaded nanoparticles into MN array patch. Both in vitro and in vivo results show this MN device presents a glucose mediated self-regulated drug release characteristic, which possesses a rapid drug release at hyperglycemic level but retarded drug release at normoglycemic level. The result indicates that the fabricated smart drug delivery system is a good candidate for the therapy of diabetes.
基金FCT for her Ph.D grant(SFRH/BD/88334/2012).Thanks are due to Aveiro University and to FCT/MEC for the-nancial support to QOPNA(FCT UID/QUI/00062/2013),CICECO-Aveiro Institute of Materials(FCT UID/CTM/50011/2013),CESAM(FCT UID/MAR/LA0017/2013)and CQE(FCT UID/QUI/0100/2013)research units,through national funds and where applicable co-nanced by the FEDER,within the PT2020 Partnership Agreement.
文摘Among the several types of inorganic nanoparticles available,silica nanoparticles(SNP)have earned their relevance in biological applications namely,as bioimaging agents.In fact,uorescent SNP(FSNP)have been explored in this-eld as protective nanocarriers,overcoming some limitations presented by conventional organic dyes such as high photobleaching rates.A crucial aspect on the use of uorescent SNP relates to their surface properties,since it determines the extent of interaction between nanoparticles and biological systems,namely in terms of colloidal stability in water,cellular recognition and internalization,tracking,biodistribution and speci-city,among others.Therefore,it is imperative to understand the mechanisms underlying the interaction between biosystems and the SNP surfaces,making surface functionalization a relevant step in order to take full advantage of particle properties.The versatility of the surface chemistry on silica platforms,together with the intrinsic hydrophilicity and biocompatibility,make these systems suitable for bioimaging applications,such as those mentioned in this review.
基金National Natural Science Foundations of China(Nos.31271028,31570984)International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality,China(No.15540723400)+2 种基金Open Foundation of State Key Laboratory for Modification of Chemical Fibers,Polymer Materials,China(No.LK1416)the Innovation Funds of Donghua University,China(No.15D310516)“111 Project” Biomedical Textile Materials Science and Technology,China(No.B07024)
文摘Controlled release of the functional factors is the key to improve clinical therapeutic efficacy during the tissue repair and regeneration. The thrce-dimensional (3D) scaffold can provide not only physical properties such as high strength and porosity hut also an optimal environment to enhance tissue regeneration. Sphingosine 1-phosphate (SIP), an angiogenlc factor, was loaded into mesoporous silica nanoparticles (MSNs) and then incorporated into poly ( L-lactic add ) ( PLLA ) nanofibrons scaffold, which was fabricated by thermally induced phase separation (TIPS) method. The prepared scaffolds were examined by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy ( SEM), and transmission electron microscopy (TEM) and compressive mechanical test. The ATR-FTIR result demonstrated the existence of MSNs in the PLLA nanofibrous scaffold. The SEM images showed that PLLA scaffold had regular pore channel, interconnected pores and nanofibrous structure. The addition of MSNs at appropriate content had no visible effect on the structure of scaffold. The compressive modulus of scaffold containing MSNs was higher than that of the scaffold without MSNs. Furthermore, fluorescein isothiocyanate (FTTC) was used as model molecule to investigate the release behavior of SIP from MSNs- incorporated PLLA (MSNs/PLLA) nanofibrons scaffold. The result showed that the composite scaffold largely reduced the initial burst release and exhibited prolonged release of FITC than MSNs. Thus, these results indicated that SIP-loaded composite uanofibrons scaffold has potential applications for bone tissue engneering.
文摘A rapid, precise, sensitive and simple method has been developed for the extraction and determination of TPT (triphenyltin), DPT (diphenyltin) and MPT (monophenyltin) in seawater samples. The procedure is based on the use of the dual functionalization of mesoporous silica with diol and Cl6 alkane groups for the collection of TPT and its derivatives, DPT and MPT, from seawater samples, followed by ethylation of the target matrices using sodium tetraethylborate (NaBEt4) and quantification by gas chromatography with pulsed flame photometric detection. The modified extraction method replaces conventional solid- and liquid-phase extraction with solid dispersion of silica nanoparticles. The partitioning of the analyte between a carefully size-selected silica nanoparticles (solid phase) and a liquid phase occurs as the solid moves through the sample as a colloidal sol. By tailoring the size of the particles to approximately 250 nm in diameter, they can be easily dispersed in aqueous solution, without the need for any mechanical or hand shaking and the solid can then be readily recovered, together with the analytes, by simple filtration or centrifugation. Recoveries of TPT, DPT and MPT chloride spiked matrices rang from 87.3±1.1 to 98.1±1.3 in seawater samples (n = I 1 samples). The limit of detection obtained was typically in the range of 0.1-3 ng Sn/L. The proposed method shows excellent linearity in the range of 0.5-2 ng Sn/L and good repeatability (RSD 〈 5% at 0.02 ng TPT (as Sn)/L). The method performance is demonstrated with real seawater samples.
基金Funded by the National Natural Science Foundation of China(No.81201197)
文摘Colloidal mesoporous silica nanoparticles functionalized with carboxy-terminated polyethylene glycol(CMS-PEG-COOH) were successfully synthesized by covalently grafting dicarboxy-terminated polyethylene glycol(HOOC-PEG-COOH) on the surface of the amino functionalized CMS nanoparticles with amide bond as a cross linker. Moreover, the structural and particle properties of CMS-PEG-COOH were characterized by nuclear magnetic resonance spectroscopy(1 H-NMR), transmission electron microscopy(TEM), dynamic light scattering(DLS), nitrogen adsorption-desorption measurements, X-ray diffraction(XRD), and Fourier transform infrared spectroscopy(FT-IR). The nanomaterials presented a relatively uniform spherical shape morphology with diameters of about 120 nm,and favorable dispersibility in weak acid solution. The CMSPEG-COOH exhibited no changes in the state of amorphous, while the mesopores sizes of 5.25 nm might provide the nanomaterials with large capacity for the loading and releasing of drugs. So the results indicated that CMSPEG-COOH might be a critical nanomaterial for drug delivery system in the future.
文摘Enhanced oil recovery(EOR)processes are applied to recover trapped or residual oil in the reservoir rocks after primary and secondary recovery methods.Changing the wettability of the rock from oil-wet to water-wet is named wettability alteration.It is an important factor for EOR.Due to their unique properties,nanoparticles have gained great attention for improving oil recovery.Despite the promising results,the main challenges of applying nanoparticles are related to the colloidal stability of the nanofuids in the harsh conditions of the reservoirs.In recent years,polymer-grafted nanoparticles have been considered as novel promising materials for EOR.The obtained results showed that adding a hydrophobic agent trimethoxy(propyl)silane on the surface of modifed silica nanoparticles with polyethylene glycol methyl ether has an efective role in improving retention and wettability alteration,especially in the oil-wet substrate due to hydrophobic interaction.The modifed silica nanoparticle by mixed polyethylene glycol methyl ether(Mn~5000)and trimethoxy(propyl)silane showed a proper performance at a concentration of 1000 ppm and a salinity range of 2000-40,000 ppm.The obtained fndings can help for a better understanding of the silica nanofuid modifcation with both hydrophilic and hydrophobic agents for the EOR application of near-wellbore.
基金Support from the National Natural Science Foundation of China(Grant No. 51704315)。
文摘In petroleum industry, crude oil emulsions are commonly formed in oilfields. The asphaltenes and fine particles in crude oil may affect the stability of the emulsions by adsorbing at the water/oil interface. In this research, the effect of silica nanoparticles and asphaltenes on emulsion stability is explored first. The asphaltenes are proved to benefit emulsion stability. Unlike the asphaltenes, however, the modified silica nanoparticles may have positive or negative effect on emulsion stability, depending on the asphaltene concentration and aggregation degree in the emulsions. Further, it is confirmed by conducting interfacial experiment that the asphaltenes and particles can adsorb at the interface simultaneously and determine the properties of the interfacial layer. More in-depth experiments concerning contact angle and asphaltene adsorption amount on the particles indicate that the asphaltenes can modify the wettability of the particles. Higher concentration and lower aggregation degree of the asphaltenes can increase their adsorption amount on the surface of particles and then improve the modification effectiveness of the particles. Resultantly, the particles with good modification effectiveness can enhance the emulsion stability while the particles with poor modification effectiveness will weaken the emulsion stability.
文摘The effect of silica nanoparticles on the rheological characteristics of water-in-heavy oil emulsions has been investigated.Enhanced oil recovery methods for heavy oil production(most especially,thermal fluid injection)usually result in the formation of water-in-oil(W/O)emulsion.In reality,the emulsion produced also contains some fine solid mineral particles such as silica,which,depending on its quantity,may alter the viscosity and/or rheological properties of the fluid.A series of binary-component emulsions were separately prepared by dispersing silica nanoparticles[phase fraction,βs,=0.5%–5.75%(wt/v)]in heavy oil(S/O suspension)and by dispersing water[water cut,θw=10%–53%(v/v)]in heavy oil(W/O emulsion).Ternary-component emulsions comprising heavy oil,water droplets and suspended silica nanoparticles(S/W/O)were also prepared with similar ranges ofθw andβs.The viscosity was measured at different shear rates(5.1–1021.4 s-1)and temperatures(30–70°C).Both binary-component and ternary-component emulsion systems were observed to exhibit nonNewtonian shear thinning behaviour.The viscosity of the heavy oil and W/O emulsions increased in the presence of silica nanoparticles.The effect was,however,less signifi cant belowβs=2%(wt/v).Moreover,a generalized correlation has been proposed to predict the viscosity of both binary-component and ternary-component emulsions.
基金supported by the National Natural Science Foundation of China(Nos.22075049,22305042,22305041,21875043,22088101,21905052,and 51961145403)the National Key R&D Program of China(No.2018YFA0209401)+4 种基金the Key Basic Research Program of Science and Technology Commission of Shanghai Municipality(No.22JC1410200)the Natural Science Foundation of Shanghai(Nos.22ZR1478900 and 20490710600)the Shanghai Science and Technology Innovation Action Plan Morning Star Project(Sail Special,Nos.20QA1401200,22YF1402200,and 23YF1401900)the Shanghai Pilot Program for Basic Research-Fudan University(No.22TQ004)the Fundamental Research Funds for the Central Universities(No.20720220010).
文摘Due to the amphiphilic nature of phospholipids in the cell membrane,the amphipathicity of the nanomedicine plays a crucial role in the endocytosis.However,limited biological characterization methods restrict the study of the state of nanoparticles with different amphiphilicities on cell membranes.The understanding of interaction of amphiphilic particle with cell membrane is still lacking.Herein,by combining the dissipative particle dynamics(DPD)with the framework construction of mesoporous silica nanoparticles(MSNs),we demonstrate the enhanced endocytosis induced by the hydrophobicity.DPD results confirm that the presence of hydrophobic groups on the surface of nanoparticles can disturb the integrity of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine(POPC)membrane and induce activation of phospholipids to a higher energy level,thereby facilitating the wrapping of nanoparticles.To validate the simulation findings,uniform MSNs with hydrophilic pure silica framework and two types of amphiphilic MSNs with varying hydrophilic organic groups in the framework are rationally synthesized by using different silane precursors.The obtained three kinds of MSNs show similar diameter(~100 nm)and mesopores(~2 nm),but distinct hydrophobicity/hydrophilicity ratio.The phenyl-bridged MSN with a carbon content of 27.1%exhibits enhanced cellular uptake,consistent with the theoretical simulation results.This work sheds light on how the surface amphipathicity influences endocytosis through the interaction with cell membrane.
基金funded by Key R&D Program of Shandong Province(2021ZDSYS18)National Natural Science Foundation of China(52172147)+1 种基金Natural Science Foundation of Shandong Province(ZR2021MC034,ZR2021MB035 and ZR2022MB095)QUTJBZ Program(2022JBZ01-05).
文摘Conductive hydrogels have garnered considerable interest for their applications in wearable electronic skins,owing to their superior properties.Nevertheless,challenges persist,including low sensitivity,poor cyclic stability,and limited tolerance to extreme conditions.This study develops a novel liquid metal-based conductive hydrogel with a dual cross-linked polyacrylic acid(PAA)matrix,employing both“soft”coordination and“hard”covalent cross-linking mechanisms.This hybrid network is formulated using guar gum(GG)-stabilized gallium(Ga)droplets,which catalyze the copolymerization of vinyl-hybrid silica nanoparticles(VSNPs)and acrylic acid(AA).The resultant Ga3+ions interact with carboxyl groups in the PAA,forming soft coordination links that enhance the hydrogel’s rapid gelation.The incorporation of VSNPs significantly enhances the hydrogel’s elasticity,toughness,and low-temperature resilience without glycerol.Notably,its intrinsic moldability,adhesion,and self-healing properties are retained.Applied as a strain sensor,this hydrogel demonstrates a high gauge factor(GF)of 17.4,responsive time of 250 ms for both activation and recovery,an ultra-low detection limit of 0.1%,and excellent durability over 800 cycles at 100%strain.Short-term immersion in a glycerol solution(20 min)further augments its stretchability to 2688%and GF to 28.1 across a strain range of 1325%–1450%,broadening its operational ranges to 0–1450%at−18°C.Prolonged exposure(4 h)also improves water retention and high-temperature resistance,making this hydrogel a promising material for sustainable,high-performance wearable electronics.