Highly Efficient Heavy-Metal-Ion Removal from Shellfish Processing Liquid with Low Protein and Polysaccharide Loss by Hybrid Mesoporous Silica Diol-APDC-SBA15

Heavy metal ions in shellfish products are harmful to human health,and their removal with low nutrient loss remains challenging.Herein,a new type of mesoporous silica(SBA15),modified internally with ammonium pyrrolidine dithiocarbamate(APDC)and externally with alkyl-diol groups,which was named as Diol-APDC-SBA15,was successfully developed and characterized by powder X-ray diffraction patterns,nitrogen adsorption,and Fourier transform infrared spectroscopy.The solutions with lead,chromium,cadmium,and copper were used to investigate the adsorption capacity of Diol-APDC-SBA15.Diol-APDC-SBA15 was adopted to remove heavy metals from cooking liquids of clams(Ruditapes philippinarum),hydrolysate liquids of oysters(Ostrea gigas Thunberg),and polysaccharide solution from the cooking liquid of R.philippinarum.The efficiencies of removing heavy metal ions and the loss rates of proteins and polysaccharides were examined.The results showed that the adsorption capacities of Diol-APDCSBA15 for Pb,Cr,Cd,and Cu in standard heavy-metal solutions were 161.4,166.1,29.6,and 60.2mgg^(−1),respectively.The removal efficiency of Diol-APDC-SBA15 for Pb in the three shellfish processing liquids ranged from 60.5%to 99.6%.The Cr removal efficiency was above 99.9%in the oyster hydrolysate liquid.Meanwhile,the percentages of polysaccharide loss were 5.5%and 3.7%in the cooking liquid of clam and polysaccharide solution,respectively,and the protein loss was 1.2%in the oyster hydrolysate liquid.Therefore,the Diol-APDC-SBA15 material exhibits a great potential application in the removal of heavy metals from shellfish processing liquids with low losses of proteins and polysaccharides.

Mesoporous silica nanoparticles with chiral pattern topological structure function as“antiskid tires”on the intestinal mucosa to facilitate oral drugs delivery

The weak adhesion between nanocarriers and the intestinal mucosa was one of the main reasons caused the failure in oral delivery.Inspired by the“antiskid tires”with complex chiral patterns,mesoporous silica nanoparticles AT-R@CMSN exhibiting geometrical chiral structure were designed to improve the surface/interface roughness in nanoscale,and employed as the hosting system for insoluble drugs nimesulide(NMS)and ibuprofen(IBU).Once performing the delivery tasks,AT-R@CMSN with rigid skeleton protected the loaded drug and reduced the irritation of drug on gastrointestinal tract(GIT),while their porous structure deprived drug crystal and improved drug release.More importantly,AT-R@CMSN functioned as“antiskid tire”to produce higher friction on intestinal mucosa and substantively influencedmultiple biological processes,including“contact”,“adhesion”,“retention”,“permeation”and“uptake”,compared to the achiral S@MSN,thereby improving the oral adsorption effectiveness of such drug delivery systems.By engineering AT-R@CMSN to overcome the stability,solubility and permeability bottlenecks of drugs,orally administered NMS or IBU loaded AT-R@CMSN could achieve higher relative bioavailability(705.95%and 444.42%,respectively)and stronger anti-inflammation effect.In addition,AT-R@CMSN displayed favorable biocompatibility and biodegradability.Undoubtedly,the present finding helped to understand the oral adsorption process of nanocarriers,and provided novel insights into the rational design of nanocarriers.

Core-shell-embedded Mesoporous Silica Capsules for Atmospheric Water Harvesting

A one-step ultrasonic mechanical method was used to synthesize a kind of atmospheric water harvesting material with high water harvesting performance in a wide relative humidity(RH)range,especially at low RH(RH<40%),namely,mesoporous silica capsule(MSC)with core-shell structure.Transmission electron microscopy(TEM),nitrogen adsorption and other characterization techniques were used to study the formation process of nano-microspheres.A new mechanism of self-adaptive concentration gradient regulation of silicon migration and recombination core-shell structure was proposed to explain the formation of a cavity in the MSC system.The core-shell design can enhance the specific surface area and pore volume while maintaining the monodispersity and mesoporous size.To study the water harvesting performance of MSC,solid silica nanoparticles(SSN)and mesoporous silica nanoparticles(MSN)were prepared.In a small atmospheric water collection test(25℃,40%RH),the water vapour adsorption and desorption kinetics of MSC,SSN,MSN and a commercial silica gel(CSG)were compared and analyzed.The results show that the MSC with mesoporous channels and core-shell structure can provide about 0.324 gwater/gadsorbent,79%higher than the CSG(0.181 gwater/gadsorbent).It is 25.1%higher than that of 0.259 gwater/gadsorbentof un-hollowed MSN and 980%higher than that of0.03 gwater/gadsorbentof un-hollowed SSN.The material has a large specific surface area and pore volume,simple preparation method and low cost,which provides a feasible idea for realising atmospheric water collection in arid and semi-arid regions.

Effect of salvianolic acid B-loaded mesoporous silica nanoparticles on myocardial ischemia-reperfusion injury

Background:Currently,no drugs can specifically improve clinical cardiac ischemia-reperfusion injury or the prognosis of hemodialysis.Salvianolic acid B(SalB)is a widely used cardiac protectant;however,its clinical application is limited by its low oral bioavailability and poor intestinal absorption.The exploration of its preparation and clinical applications has become a research hotspot in recent years.Methods:To determine whether mesoporous silica nanoparticles(MSNs)efficiently delivered SalB to the heart and SalB@MSNs-RhB reduced myocardial ischemia-reperfusion injury,we constructed a myocardial ischemia-reperfusion male rat model,hypoxia/reoxygenation cardiomyocytes,and treated them with SalB@MSNs-RhB.Results:SalB@MSNs-RhB showed improved bioavailability,therapeutic effect,heightened JAK2/STAT3-dependent pro-survival signaling,and antioxidant responses,thereby protecting cardiomyocytes from ischemia-reperfusion injury-induced oxidative stress and apoptosis.Conclusion:This use of SalB-loaded nanoparticles and investigation of their mechanism of action may provide a new strategy for treating cardiomyocytes.Thus,hypoxia/reoxygenation promotes the clinical application of SalB.

Location and size regulation of manganese oxides within mesoporous silica for enhanced antibiotic degradation

Refractory antibiotics in domestic wastewater are hard to be completely eliminated by conventional methods,and then lead to severe environmental contamination and adverse effects on public health.In present work,advanced oxidation processes(AOPs)are adopted to remove the antibiotic of sul-fachloropyridazine(SCP).Nanosized Mn_(2)O_(3) was fabricated on the SBA-15 material to catalytically acti-vate potassium peroxydisulfate(PDS)to generate reactive oxygen radicals of.OH and SO_(4).for SCP degradation.The effects of location and size of Mn_(2)O_(3) were explored through choosing either the as-made or template free SBA-15 as the precursor of substrate.Great influences from the site and size of Mn_(2)O_(3) on the oxidation activity were discovered.It was found that Mn_(2)O_(3) with a large size at the exterior of SBA-15(Mn-tfSBA)was slightly easier to degrade SCP at a low manganese loading of 1.0-2.0 mmol.g;however,complete SCP removal could only be achieved on the catalyst of Mn_(2)O_(3) with a refined size at the interior of SBA-15(Mn-asSBA).Moreover,the SO_(4).species were revealed to be the decisive radicals in the SCP degradation processes.Exploring the as-made mesoporous silica as a support provides a new idea for the further development of environmentally friendly catalysts.

Alginate encapsulated mesoporous silica nanospheres as a sustained drug delivery system for the poorly water-soluble drug indomethacin

We applied a combination of inorganic mesoporous silica material,frequently used as drug carriers,and a natural organic polymer alginate(ALG),to establish a sustained drug delivery system for the poorly water-soluble drug Indomethacin(IND).Mesoporous silica nanospheres(MSNs)were synthesized using an organic template method and then functionalized with aminopropyl groups through postsynthesis.After drug loading into the pores of aninopropyl functionalized MSNs(AP-MSNs),IND loaded AP-MSNs(IND-AP-MSNs)were encapsulated by ALG through the ionic interaction.The effects of surface chemical groups and ALG layer on IND release were systematically studied using scanning electron microscopy(SEM),transmission electron microscopy(TEM),nitrogen adsorption,zetapotential analysis and TGA analysis.The surface structure and surface charge changes of the ALG encapsulated AP-MSNs(ALG-AP-MSNs)were also investigated.The results showed that sustained release of IND from the designed drug delivery system was mainly due to the blockage effect from the coated ALG.We believe that this combination will help designing oral sustained drug delivery systems for poorly water-soluble drugs.

Determination of Average Wall Thickness of Mesoporous Silica

Small Angle X-ray Scattering (SAXS) experiment using Synchrotron Radiation as X-ray source was used to determine the average wall thickness of mesoporous silica prepared by condensation of tetraethylorthosilicate (TEOS) using non-ionic alkylpolyethyleneoxide (AEO9) surfactant as templates. The results agreed with that of high-resolution TEM (HRTEM) measurement.

Synthesis of Highly ordered Large Size Mesoporous Silica and Effect of Stabilization as Enzyme Supports in Organic Solvent

FSM 16, MCM 41 and SBA 15 types of hexagonal mesoporous silica with a highly ordered 2 dimensional structure were synthesized by using different silicon sources and surfactants. In the 2 dimensional silicate framework, pore size can be uniformly controlled by the combined use of the surfactants having different alkyl chain lengths and the swelling agents(triisopropyl benzene). The pore diameter of FSM 16 and MCM 41 can be expanded to be 10 nm, SBA 15 to be 15 nm. The crystal regularity was decreased with the increase of the pore diameter. In FSM 16 derived from kanemite(silicon source) and MCM 41 from water glass, their anionic characteristics on the pore wall may be stronger than those of SBA 15 derived from oligomeric tetramethoxysilane(TMOS). We have successfully used FSM 16 and MCM 41 to immobilize the enzyme having cationic residues below isoelectric point. The level of adsorption of enzymes in FSM 16 and MCM 41 was relatively high, but was low in SBA 15 support. The mechanism of enzyme to be adsorbed in mesoporous silica was suggested to be the ionic interactions. In aqueous solutions, horseradish peroxidase(HTP) was immobilized in FSM 16 with 8.9 nm mesopores and the highest loading amount(183 mg/mg FSM) was obtained, but for the FSM 16 of pore diameter 30 nm only an amount of 28 mg/mg FSM was obtained. The catalytic activity in the organic solvent was high when HRP was immobilized in FSM 16 and MCM 41, but it was low in case of SBA 15.

Biomineralization Precursor Carrier System Based on Carboxyl- Functionalized Large Pore Mesoporous Silica Nanoparticles

Bone and teeth are derived from intrafibrillarly mineralized collagen fibrils as the second level of hierarchy.According to polymer-induced liquid-precursor process,using amorphous calcium phosphate precursor(ACP)is able to achieve intrafibrillar mineralization in the case of bone biomineral in vitro.Therefore,ACP precursors might be blended with any osteoconductive scaffold as a promising bone formation supplement for in-situ remineralization of collagens in bone.In this study,mesoporous silica nanoparticles with carboxyl-functionalized groups and ultra large-pores have been synthesized and used for the delivery of liquid like biomimetic precursors(ACP).The precursor delivery capacity of the nanoparticles was verified by the precursor release profile and successful mineralization of 2D and 3D collagen models.The nanoparticles could be completely degraded in 60 days and exhibited good biocompatibility as well.The successful translational strategy for biomineralization precursors showed that biomineralization precursor laden ultra large pore mesoporous silica possessed the potential as a versatile supplement in demineralized bone formation through the induction of intrafibrillar collagen mineralization.

Characterization of modified mesoporous silica nanoparticles as vectors for siRNA delivery

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.

Dissolution improvement of fenofibrate by melting inclusion in mesoporous silica

In this study,using mesoporous silica for the solubility enhancement of poorly watersoluble drug was investigated.Although the incorporating drug into mesoporous silica is generally performed through the solvent method,the new melting method was proposed in the present study.Fenofibrate,a poorly water-soluble drug,was incorporated into mesoporous silica by solvent method and melting method.The obtained samples were observed by SEM and their physicochemical properties were evaluated by PXRD and DSC measurement.The dissolution and supersaturated property were also investigated.The results from SEM,PXRD and DSC measurement showed that drug could be loaded into pore via the melting method as well as by the solvent method.The drug loaded quantity depended on the pore volume.Drug up to 33%could be incorporated into mesoporous silica and existed in amorphous state.When drug was overloaded or difficulty in incorporation into pore was found,recrystallization of drug occurred at the outer surface of mesoporous silica.From the dissolution test,samples prepared by solvent method and melting method gave the supersaturated drug concentration which sample from melting method showed superior dissolution to the one from solvent method.From this study,drug was efficiently incorporated into mesoporous silica by the melting method which is a simple and solvent-free process,and the aqueous solubility enhancement of poorly watersoluble drug was achieved.

Synthesis of Cubic Mesoporous Silica MCM-48by Mixed Micellar Templates

High-quality mesoporous silica MCM-48 were synthesized under basic conditions by using the mixture of cetyltrimethylammonium bromide (CTAB) and alkylamine (CnNH2n+3, n=8,10,12,14, respectively) as templates. The effects of the alkylamines with different chain lengths (n=8,10,12,14,16,18, respectively) on the silica structure were investigated.

Bilirubin adsorption property of mesoporous silica and amine-grafted mesoporous silica

Nephritic, hepatic and immune failures would lead to the overload of endogenous toxic molecules(e.g. bilirubin, cholic acid, uric acid, creatinine etc.) in human bodies. It is fatal in most cases and extracorporeal blood purification(ECBP) is powerful first-aid therapy. Adsorbents are key parts of ECBP apparatus. Mesoporous silicas should be promising candidates for these medical adsorbents, but there is no report about this. Herein, pure and amine-grafted mesoporous silicas have been applied to adsorb bilirubin, cholic acid, uric acid, creatinine and phenobarbital for the first time. These mesoporous materials show high adsorption capacities for bilirubin and uric acid in phosphate buffer solution(PBS). Effects of pore sizes, amine-modification, temperature and ionic strength on their bilirubin adsorption capacities have been studied in detail.

Dual responsive block copolymer coated hollow mesoporous silica nanoparticles for glucose-mediated transcutaneous drug delivery

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.

Development of phosphonate-terminated magnetic mesoporous silica nanoparticles for pH-controlled release of doxorubicin and improved tumor accumulation

In this study,phosphonate-terminated magnetic mesoporous nanoparticles(pMMSNs)was designed by incorporation of MNPs in the center of mesoporous silica nanoparticles(MSNs)and followed by grafting phosphonate group on to the surface of MMSNs.The carrier exhibited a typical superparamagnetic feature and the saturation magnetization was 4.89 emu/g measured by vibrating sample magnetometer(VSM).pMMSNs had a spherical morphology and a pore size of 2.2 nm.FromN2 adsorption-desorption analysis,pMMSNs had a surface area of 613.4 m^(2)/g and a pore volume of 0.78 cm^(3)/g.Phosphonate modification improved the colloidal stability of MMSNs,and the hydrodynamic diameter of pMMSNs was around 175 nm.The hydrophilic phosphonate group significantly enhanced the negative surface charge of MMSNs from -19.3 mV to -28.8 mV pMMSNs with more negative surface charge had a 2.3-fold higher drug loading capacity than that of MMSNs.In addition,the rate and amount of release of doxorubicin(DOX)from DOX/pMMSNs was pH-dependent and increased with the decrease of pH.At pH 7.4,the release amount was quite low and only approximately 17wt%ofDOXwasreleasedin48h.AtpH5.0and3.0,the release rate increased significantly and the release amount achieved 31 wt%and 60 wt%in 48 h,respectively.To evaluate the magnetic targeting performance ofpMMSNs,FITC labeledpMMSNswas injected into mice bearing S180 solid tumor.FITC labeledpMMSNscontrolled by an external magnetic field showed higher tumor accumulation and lower normal tissue distribution.

Thermal conductivity of a kind of mesoporous silica SBA-15

Mesoporous silica SBA-15 consists of uniform hexagonal,unconnected cylindrical channels with diameters that can be tuned within a range of 1.5 nm-30 nm,and is thought to have a special thermal conductivity.The theoretical investigation of the shell thermal conductivity of the mesoporous silica is performed in the relaxation time approximation in this paper and an available one-dimensional heat transfer model is used to predict the effective thermal conductivity(ETC) of the mesoporous silica.The experimental result of the ETC is also presented for comparison.The shell thermal conductivity of the mesoporous silica decreases with mesochannel radius increasing or wall thickness decreasing,but does not strictly decrease with porosity increasing.The thermal radiation possibly plays a primary role in heat transfer at the large porosity scale.The predicted ETC of SBA-15 with only conduction considered is quite low at the large porosity,even lower than the thermal conductivity of the silica aerogels.To realize it,doping carbon or other matters which can strongly absorb infrared light into SBA-15 is a possible way.

Polymerization of Methyl Methacrylate with Samarocene Complex Supported on Mesoporous Silica

Samarocene complex was supported on a series of mesoporous silica with various pore sizes. Polymerization of methyl methacrylate (MMA) by these catalysts provide highly syndiotactic PMMAs with higher molecular weights compared with those obtained by solution polymerization with homogeneous catalyst system.

A vacuum nano-casting route to magnetite cores/mesoporous silica shell composites

Hollow mesoporous silica spheres with magnetite cores(HMSMC) have been fabricated by Vacuum Nano-casting Route. The amount of magnetite cores and saturation magnetization value can be easily adjusted by changing the concentration of iron nitrate solution used in the synthesis procedure. Furthermore, the as-prepared HMSMCs still maintain narrow mesopore distribution, high surface area and large pore volume after the hollow cores of hollow mesoporous silica spheres were filled with magnetite particles. Specially, when the saturation magnetization value of as-prepared HMSMCs reaches 22.0 emu/g, the surface area and pore volume of corresponding HMSMCs are 149 m^2/g and 0.19 cm^3/g, respectively, and the pore size is 2.30 nm. The corresponding samples are characterized by X-ray diffraction, N_2 sorption isotherms, transmission electron microscopy and vibrating-sample magnetometer.

Incorporation of Sphingosine 1-Phosphate Loaded Mesoporous Silica Nanoparticles into Poly ( L-lactic acid ) Nanofibrous Scaffolds for Bone Tissue Engineering

Controlled release of the functional factors is the key to improve clinical therapeutic efficacy during the tissue repair and regeneration.The three-dimensional(3D)scaffold can provide not only physical properties such as high strength and porosity but also an optimal environment to enhance tissue regeneration.Sphingosine1-phosphate(S1P),an angiogenic factor,was loaded into mesoporous silica nanoparticles(MSNs)and then incorporated into poly(L-lactic acid)(PLLA)nanofibrous 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(FITC)was used as model molecule to investigate the release behavior of S1P from MSNsincorporated PLLA(MSNs/PLLA)nanofibrous 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 S1P-loaded composite nanofibrous scaffold has potential applications for bone tissue engineering.

Room-Temperature Synthesis of Fe-containing Mesoporous Silica

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