Facile synthesis of chromium chloride/poly(methyl methacrylate) core/shell nanocapsules by inverse miniemulsion evaporation method and application as delayed crosslinker in secondary oil recovery

Cr(III)ehydrolyzed polyacrylamide(HPAM)gels have been extensively studied as a promising strategy controlling waste water production for mature oilfields.However,the gelation time of the current technologies is not long enough for in-depth placement.In this study,we report a novel synthesis method to obtain chromium chloride/poly(methyl methacrylate)(PMMA)nanocapsules which can significantly delay the gelation of HPAM through encapsulating the chromium chloride crosslinker.The chromium chloride-loaded nanocapsules(CreNC)are prepared via a facile inverse miniemulsion evaporation method during which the hydrophobic PMMA polymers,pre-dispersed in an organic solvent,were carefully controlled to precipitate onto stable aqueous miniemulsion droplets.The stable aqueous nanodroplets(W)containing Cr(III)are dispersed in a mixture of organic solvent(O1)with PMMA and nonsolvent medium(O2)to prepare an inverse miniemulsion.With the evaporation of the O1,PMMA forms CreNCs around the aqueous droplets.The CreNCs are readily transferred into water from the organic nonsolvent phase.The CreNCs exhibit the tunable size(358-983 nm),Cr loading(7.1%-19.1%),and Cr entrapment efficiency(11.7%-80.2%),with tunable zeta potentials in different PVA solutions.The CreNCs can delay release of Cr(III)and prolong the gelation time of HPAM up to 27 days.

Enhanced antibacterial activity of cotton via silver nanocapsules deposited by atmospheric pressure plasma jet

In this work,the antibacterial activity of cotton containing silver nanocapsules prepared by atmospheric pressure plasma(APP)deposition is investigated.The nanocapsules consist of a shell and a silver nanoparticle(Ag NP)core,where the core is used to bring antibacterial activity,and the shell is utilized to suppress the potential toxicity of Ag NPs.The surface morphology and the elements of the samples are analyzed by scanning electron microscopy(SEM),energy dispersive x-ray and x-ray photoelectron spectroscopy(XPS).The SEM results show that the skin of the cotton fibers will fall off gradually after APP treatment over 3 min,and the XPS results show that the Ag content will rise to 1.6%after APP deposition for 10 min.Furthermore,the antimicrobial activity tests show that the reduction rates of Escherichia coli and Staphylococcus aureus can achieve 100%when the sample is treated for 10 min,which exhibits excellent antibacterial activity.In addition,the UV absorption properties of the cotton will also be correspondingly improved,which brings a broader application prospect for antibacterial cotton.

Microwave Absorption of Crystalline Fe/MnO@C Nanocapsules Embedded in Amorphous Carbon

Crystalline Fe/MnO@C core–shell nanocapsules inlaid in porous amorphous carbon matrix(FMCA)was synthesized successfully with a novel confinement strategy.The heterogeneous Fe/MnO nanocrystals are with approximate single-domain size which gives rise to natural resonance in 2–18 GHz.The addition of MnO2 confines degree of graphitization catalyzed by iron and contributes to the formation of amorphous carbon.The heterogeneous materials composed of crystalline–amorphous structures disperse evenly and its density is significantly reduced on account of porous properties.Meanwhile,adjustable dielectric loss is achieved by interrupting Fe core aggregation and stacking graphene conductive network.The dielectric loss synergistically with magnetic loss endows the FMCA enhanced absorption.The optimal reflection loss(RL)is up to−45 dB,and the effective bandwidth(RL<−10 dB)is 5.0 GHz with 2.0 mm thickness.The proposed confinement strategy not only lays the foundation for designing high-performance microwave absorber,but also offers a general duty synthesis method for heterogeneous crystalline–amorphous composites with tunable composition in other fields.

Interconnected carbon nanocapsules with high N/S co-doping as stable and high-capacity potassium-ion battery anode

Carbonaceous materials have drawn much attention in potassium-ion batteries (PIBs) due to their low price and superior physicochemical properties. However, the application of carbonaceous materials in PIB anodes is hindered by sluggish kinetics and large volume expansion. Herein, N/S co-doped carbon nanocapsule (NSCN) is constructed for superior K+ storage. The NSCN possesses 3D nanocapsule framework with abundant meso/macropores, which guarantees structural robustness and accelerates ions/electrons transportation. The high-level N/S co-doping in carbon matrix not only generates ample defects and active sites for K+ adsorption, but also expands interlayer distance for facile K+ intercalation/deintercalation. As a result, the NSCN electrode delivers a high reversible capacity (408 mAh g^(−1) at 0.05 A g^(−1)), outstanding rate capability (149 mAh g^(−1) at 5 A g^(−1)) and favorable cycle stability (150m Ah g^(−1) at 2 A g^(−1) after 2000 cycles). Ex situ TEM, Raman and XPS measurements demonstrate the excellent stability and reversibility of NSCN electrode during potassiation/depotassiation process. This work provides inspiration for the optimization of energy storage materials by structure and doping engineering.

Sustained‑Release Nanocapsules Enable Long‑Lasting Stabilization of Li Anode for Practical Li‑Metal Batteries

A robust solid-electrolyte interphase(SEI)enabled by electrolyte additive is a promising approach to stabilize Li anode and improve Li cycling efficiency.However,the self-sacrificial nature of SEI forming additives limits their capability to stabilize Li anode for long-term cycling.Herein,we demonstrate nanocapsules made from metal–organic frameworks for sustained release of LiNO3 as surface passivation additive in commercial carbonate-based electrolyte.The nanocapsules can offer over 10 times more LiNO3 than the solubility of LiNO3.Continuous supply of LiNO3 by nanocapsules forms a nitride-rich SEI layer on Li anode and persistently remedies SEI during prolonged cycling.As a result,lifespan of thin Li anode in 50μm,which experiences drastic volume change and repeated SEI formation during cycling,has been notably improved.By pairing with an industry-level thick LiCoO2 cathode,practical Li-metal full cell demonstrates a remarkable capacity retention of 90%after 240 cycles,in contrast to fast capacity drop after 60 cycles in LiNO3 saturated electrolyte.

Boosting of the enhanced permeability and retention effect with nanocapsules improves the therapeutic effects of cetuximab

Objective:The introduction of therapeutic antibodies(tAbs)into clinical practice has revolutionized tumor treatment strategies,but their tumor therapy efficiency is still far below expectations because of the rapid degradation and limited tumor accumulation of tAbs.Methods:We developed a nanocapsule-based delivery system to induce the self-augmentation of the enhanced permeability and retention(EPR)effect.This system constantly penetrated across the blood-tumor barrier into the tumor while avoiding the attack of tAbs by the immune system.The biodistribution and therapeutic effect were tested with single dose administration of nanocapsule-tAbs in vivo.Results:The accumulation of Nano(cetuximab)within subcutaneous PC9 tumors was gradually enhanced over 6 days after single dose administration,which was contrary to the biodistribution of native cetuximab.Nano(cetuximab)accumulated in tumor tissues via the EPR effect and released cetuximab.The released cetuximab acted on vascular endothelial cells to destroy the blood-tumor barrier and induce self-augmentation of the EPR effect,which in turn contributed to further tumor accumulation of long-circulating Nano(cetuximab).Compared with single dose administration of native cetuximab,Nano(cetuximab)showed an effective tumor suppressive effect for 3 weeks.Conclusions:The nanocapsule-based delivery system efficiently delivered tAbs to tum or tissues and released them to boost the EPR effect,which facilitated further tumor accumulation of the tAbs.This novel self-augmentation of the EPR effect facilitated by the biological characteristics of tAbs and nanotechnology contributed to the improvement of the therapeutic effect of tAbs,and stimulated new ideas for antibody-based tumor therapy.

Gas-blasting nanocapsules to accelerate carboplatin lysosome release and nucleus delivery for prostate cancer treatment

To improve therapeutic effect and reduce severely side effects of carboplatin(CBP),the gas-generating nanocapsules were developed to accelerate CBP lysosome release and nucleus delivery.CBP/SB-NC was prepared by co-loading CBP and NaHCO 3(SB)in nanocapsules using w/o/w emulsification solvent evaporation.They exhibited vesicle-like spherical morphology,uniform particle size and negative zeta potential.Reaching the tumor site with a relatively high concentration is the first step for CBP delivery and the results showed that CBP/SB-NC could effectively increase drug accumulation at tumor site.After that,the drug delivery carriers need to be internalized into tumor cells and the in vitro cellular uptake ability results showed CBP/SB-NC could be internalized into RM-1 cells more efficient than CBP solution.After internalized by RM-1 cells,the gas-blasting release process was tested in acid environment.It was demonstrated that 5 mg/ml NaHCO 3 was optimal to achieve pH-responsive gas-blasting release.In vitro release results showed that CBP significantly rapid release in acid environment(pH 5.0)compared to neutral pH(pH 7.4)(P<0.05).Meanwhile,TEM and the change of the concentration of H+results exhibited that the explosion of CBP/SB 5-NC was more easily happened in lysosome acid environment(pH 5.0).The blasting release can accelerate CBP lysosome release to cytoplasm.Furthermore,the nucleus delivery results showed CBP/SB 5-NC can promote pH-triggered rapid nucleus delivery.And the results of Pt-DNA adduct assay showed that the binding efficiency between CBP and DNA of CBP/SB 5-NC was higher than CBP solution.At last,in vitro and in vivo anti-tumor efficacy proved that CBP/SB 5-NC could enhance anti-tumor activity for prostate cancer therapy.CBP/SB 5-NC also showed superior safety in vitro and in vivo by hemolysis assay and histopathological study.All of the results demonstrate that CBP/SB 5-NC would be an efficient gas-blasting release formulation to enhance prostate cancer treatment.

The Role of Surfactant and Costabilizer in Controlling Size of Nanocapsules Containing TEGDMA in Miniemulsion

Nanocapsules with triethylene glycol dimethacrylate （TEGDMA） as core material and polyurethane as wall material used for self-healing bonding resin were prepared by interfacial polycondensation in miniemulsion. The influence of surfactant and costabilizer concentration on nanocapsules size and stability of nanocapsules was investigated. The size and its polydispersity of the nanocapsules were measured by light-scattering particle size analyzer. When the concentration of SDS were increased from 2.5wt% to 10wt%,the size decreases from 340.5 nm to 258.3 nm, PDI decreased from 0.210 to 0.111. As the concentration of HD increased, the size and PDI were both decreased, When reaching 10wt%,the size was 258.0 nm,PDI was 0.130. SDS and HD play important effect in synthesis of Nanocapsules containing TEGDMA.By changing the surfactant and costabilizer concentration it was possible to synthesize a wide variety of nanocapsules sizes. The performance and technical parameters of nanocapsules had been researched preliminarily, which built the solid foundation for the application to the self-repairing bonding resin.

Evolution in the formation of graphene nanocapsules from coal tar pitch

It has recently been reported that coal tar pitch(CTP)can be utilised as raw material for the production of graphene nanocapsules(GNCs)because it is formed by a great quantity of aromatic organic compounds(which promote the rearrangement of double bonds by a process of polymerisation).Due to the importance of graphene and the search for a non-expensive methodology to produce it,this work used CTP to synthesise GNCs using an in situ activation technique at low temperatures and evaluating the effect of the working temperature on the formation of such nanostructures.In other words,analysing the form of the particle as the temperature rises from 600 to 900℃.As result of the experimentation,powders were obtained and analysed by the techniques of X-Ray Diffraction,Raman Spectroscopy and Microscopy,employing Field Fmission Scanning Electron Microscopy by normal mode as well as by Scanning Transmission Electron Microscopy and a High-Resolution Scanning Electron Microscopy.The results show that working with temperatures between 800 and 850℃promotes the production of GNCs,considering that their size reduces as the working temperature rises.

Study on the preparation of Pt nanocapsules

Ag@Pt core-shell nanoparticles（Ag@Pt NPs） were prepared by a co-reduction method. Pt nanocapsules with diameters of less than 10 nm were obtained by an electrochemical method. Cyclic voltammetry（CV） scanning was used to cavitate the Ag@Pt NPs, and the morphology, structure, and cavitation conditions were studied. The results indicate that the effective cavitation conditions to obtain Pt nanoparticles from Ag@Pt NPs are a scanning voltage of 0 to 0.8 V and continuous CV scanning over 2 h. This cavitation method is also applicable for the syntheses of Ir, Ru, and Ru-Pt nanocapsules.

Synthesis and Characterization of Nanocapsules of α-Fe(NiCoAl) Solid-solution

α-Fe(NiCoAl) solid-solution nanocapsules were prepared with pure powders of Fe, Ni, Co and Al by the plasma arc-discharging using a copper crucible. The shapes of the nanocapsules are in polyhedrons with the core/shell structure. The body centered cubic (BCC) phase is formed in the core. The size of the nanocapsules is in the range of 10-120 nm and the thickness of the shell is 4-11 nm. Saturation magnetization JS=150 Am2/kg and coercivity iHC=24.3 kA/m are achieved for the nanocapsules.

Synthesis and Biological Activity of Drug Delivery System Based on Chitosan Nanocapsules

Chitosan nanocapsules containing naproxen as an active ingredient were synthesized by ionic gelation method in presence of polyanion tripolyphosphate as a crosslinker. The morphology and diameter of the prepared chitosan nanoparticles was characterized using scanning electron microscopy and transition electron microscopy. Different factors affecting on the size diameter of chitosan nanoparticles such as stirring time and temperature, pH values as well as chitosan concentration were studied. Different factors affecting on the immobilization of naproxen into chitosan nanoparticles such as time, temperature and pH values were optimized. Synthesized naproxen/chitosan nanocapsules were assessed against both Gram positive bacterial strain such as Bacillus subtilis and Staphylococcus aureus and Gram negative bacterial strain such as Pseudomonas aeruginosa and Escherichia coli. Also, the antifungal activity of the naproxen/chitosan nanocapsules against Saccharomyces cerevisiae was demonstrated. Super oxide dismutase like activity of naproxen/chitosan nanocapsules will be determined.

Research Article Dynamically crosslinked nanocapsules for the efficient and serumresistant cytosolic protein delivery

Intracellular protein delivery is critical to the development of protein-based biopharmaceuticals and therapies.However,current delivery vectors often suffer from complicated syntheses,low generality among various proteins,and insufficient serum stability.Herein,we developed an enlightened cytosolic protein delivery strategy by dynamically crosslinking epigallocatechin gallate(EGCG),low-molecular-weight polyethylenimine(PEI 1.8k),and 2-acetylphenylboric acid(2-APBA)on the protein surface,hence forming the EPP-protein nanocapsules(NCs).EGCG enhanced protein encapsulation via hydrogen bonding,and reduced the positive charge density of PEI to endow the NCs with high serum tolerance,thereby enabling effective cellular internalization in serum.The formation of reversible imine and boronate ester among 2-APBA,EGCG,and PEI 1.8k allowed acid-triggered dissociation of EPP-protein NCs in the endolysosomes,which triggered efficient intracellular release of the native proteins.Such strategy therefore showed high efficiency and universality for diversities of proteins with different molecular weights and isoelectric points,including enzyme,toxin,antibody,and CRISPR(clustered regularly interspaced short palindromic repeats)-Cas9 ribonucleoprotein(RNP),outperforming the commercial protein transduction reagent PULSin and RNP transfection reagent lipofectamine CMAX.Moreover,intravenously(i.v.)injected EPP-saporin NCs efficiently delivered saporin into 4T1 tumor cells to provoke robust antitumor effect.This simple,versatile,and robust cytosolic protein delivery system holds translational potentials for the development of protein-based therapeutics.

Trojan nanobacteria hybridized with prodrug nanocapsules for efficient combined tumor therapy

Live bacteria-based drug delivery systems have been raised as promising tools for enhancing drug delivery into tumors due to their active tumor targeting and easy surface modifiability.In this work,a“Trojan nanobacteria hybrid”,E.coli@highly integrated nanocapsules(HINCs)hybrid(HINE-Hybrid),was successfully constructed with HINCs of prodrug based on covalent selfassembly and the facultative anaerobic bacterium E.coli MG 1655 for combined chemotherapy,photothermal therapy(PTT),and chemodynamic therapy(CDT).HINCs were constructed by covalent cross-linking of pillar[5]arene derivatives and cisplatin prodrug linker,which can be endocytosed and lysed to release therapeutic agents.Under the near-infrared(NIR)light(at 808 nm)irradiation,the system temperature can be significantly increased by HINCs,which further leads to the highly efficient generation of reactive oxygen species(ROS).In addition,HINE-Hybrid shows significant antitumor effects in in vitro and in vivo studies and also promotes immune cell infiltration and antitumor cytokine expression in the tumor microenvironment(TME).HINEHybrid exerts its anticancer properties efficiently due to selective enrichment and multiplication of E.coli at tumor sites,which is important for the construction of bacterial-assisted antitumor platforms.

Bio-assembled smart nanocapsules for targeted delivery of KRAS shRNA and cancer cell bioimage

The five-year survival rate for pancreatic cancer is less than 5%. However, the current clinical multimodal therapy combined with first-line chemotherapy drugs only increases the patient’s median survival from 5.0 months to 7.2 months. Consequently, a new strategy of cancer treatments is urgently needed to overcome this high-fatality disease. Through a series of biometric analyses, we found that KRAS is highly expressed in the tumor of pancreatic cancer patients, and this high expression is closely related to the poor prognosis of patients. It shows that inhibiting the expression of KRAS has great potential in gene therapy for pancreatic cancer. Given those above, we have exploited the possibility of targeted delivery of KRAS shRNA with the intelligent and bio-responsive nanomedicine to detect the special oxidative stress microenvironment of cancer cells and realize efficient cancer theranostics. Our observations demonstrate that by designing the smart self-assembled nanocapsules of melanin with fluorescent nanoclusters we can readily achieve the bio-recognition and bioimaging of cancer cells in biological solution or serum.The self-assembled nanocapsules can make a significant bio-response to the oxidative stress microenvironment of cancer cells and generate fluorescent zinc oxide Nanoclusters in situ for targeted cell bioimaging. Moreover, it can also readily facilitate cancer cell suppression through the targeted delivery of KRAS shRNA and low-temperature hyperthermia. This raises the possibility to provide a promising theranostics platform and self-assembled nanomedicine for targeted cancer diagnostics and treatments through special oxidative stress-responsive effects of cancer cells.

Ultrasound-triggered noninvasive regulation of blood glucose levels using microgels integrated with insulin nanocapsules

Diabetes is a serious public health problem affecting 422 million people worldwide. Traditional diabetes management often requires multiple daily insulin injections, associated with pain and inadequate glycemia control. Herein, we have developed an ultrasound-triggered insulin delivery system capable of pulsatile insulin release that can provide both long-term sustained and fast on-demand responses. In this system, insulin-loaded poly（lactic-co-glycolic acid） （PLGA） nanocapsules are encapsulated within chitosan microgels. The encapsulated insulin in nanocapsules can passively diffuse from the nanoparticle but remain restricted within the microgel. Upon ultrasound treatment, the stored insulin in microgels can be rapidly released to regulate blood glucose levels. In a chemically-induced type I diabetic mouse model, we demonstrated that this system, when activated by 30 s ultrasound administration, could effectively achieve glycemic control for up to one week in a noninvasive, localized, and pulsatile manner.

Magnetic and Microwave-absorption Properties of Graphite-coated (Fe, Ni) Nanocapsules

The structure, magnetic and microwave-absorption properties of graphite-coated （Fe, Ni） alloy nanocapsules, synthesized by the arc-discharge method, have been studied. High-resolution transmission electron microscopy shows that the nanocapsules have a core/shell structure with （Fe, Ni） alloy as the core and graphite as the shell. All （Fe, Ni） alloy nanocapsules/paraffin composites show good microwave-absorption properties. The optimal reflection loss （RL） was found for （Fe70Ni30）/C nanocapsules/paraffin composites, being -47.84 dB at 14.6 GHz for an absorber thickness of 1.99 mm, while the RL values exceeding -10 dB were found in the 12.4– 17.4 GHz range, which almost covers the Ku band （12.4–18 GHz）. For （Fe70Ni30）/C nanocapsules/paraffin composites, RL values can exceed -10 dB in the 11.4–18 GHz range with an absorber thickness of 1.91 mm, which cover the whole Ku band.

Phosphorylcholine polymer nanocapsules prolong the circulation time and reduce the immunogenicity of therapeutic proteins

Protein therap34 wherein therapeutic proteins are delivered to treat disorders, is considered the safest and most direct approach for treating diseases. However, its applications are highly limited by the paucity of efficient strategies for delivering proteins and the rapid clearance of therapeutic proteins in vivo after their administration. Here, we demonstrate a novel strategy that can significantly prolong the circulation time of therapeutic proteins as well as minimize their immunogenicity. This is achieved by encapsulating individual protein molecules with a thin layer of crosslinked phosphorylcholine polymer that resists protein adsorption. Through extensive cellular studies, we demonstrate that the crosslinked phosphorylcholine polymer shell effectively prevents the encapsulated protein from being phagocytosed by macrophages, which play an essential role in the clearance of nanoparfides in vivo. Moreover, the polymer shell prevents the encapsulated protein from being identified by immune cells. As a result, immune responses against the therapeutic protein are effectively suppressed. This work describes a feasible method to prolong the circulation time and reduce the immunogenicity of therapeutic proteins, which may promote the development and application of novel protein therapies in the treatment of diverse diseases.

Interface evolution in the platelet-like SiC@C and SiC@ SiO2 monocrystal nanocapsules

Carbon-coated SiC@C nanocapsules （NCs） with a hexagonal platelet-like morphology were fabricated by a simple direct current （DC） arc-discharge plasma method. The SiC@C NCs were monocrystalline, 120-150 nm in size, and approximately 50 nm thick. The formation of the as-prepared SiC@C NCs included nucleation of truncated octahedral SiC seeds and subsequent anisotropic growth of the seeds into hexagonal nanoplatelets in a carbon-rich atmosphere. The disordered carbon layers on the SiC@C NCs were converted into SiO2 shells of SiC@SiO2 NCs by heat treatment at 650 ℃ in air, during which the shape and inherent characteristics of the crystalline SiC core were obtained. The interface evolution from carbon to SiO2 shells endowed the SiC@SiO2 NCs with enhanced photocatalytic activity due to the hydrophilic and transparent nature of the SiO2 shell, as well as to the photosensitive SiC nanocrystals. The band gap of the nanostructured SiC core was determined to be 2.70 eV. The SiC@SiO2 NCs degraded approximately 95% of methylene blue in 160 min under visible light irradiation.