Pickering emulsion transport in skeletal muscle tissue:A dissipative particle dynamics simulation approach

Lymph node targeting is a commonly used strategy for particulate vaccines,particularly for Pickering emulsions.However,extensive research on the internal delivery mechanisms of these emulsions,especially the complex intercellular interactions of deformable Pickering emulsions,has been surprisingly sparse.This gap in knowledge holds significant potential for enhancing vaccine efficacy.This study aims to address this by summarizing the process of lymph-node-targeting transport and introducing a dissipative particle dynamics simulation method to evaluate the dynamic processes within cell tissue.The transport of Pickering emulsions in skeletal muscle tissue is specifically investigated as a case study.Various factors impacting the transport process are explored,including local cellular tissue environmental factors and the properties of the Pickering emulsion itself.The simulation results primarily demonstrate that an increase in radial repulsive interaction between emulsion particles can decrease the transport efficiency.Additionally,larger intercellular gaps also diminish the transport efficiency of emulsion droplet particles due to the increased motion complexity within the intricate transport space compared to a single channel.This study sheds light on the nuanced interplay between engineered and biological systems influencing the transport dynamics of Pickering emulsions.Such insights hold valuable potential for optimizing transport processes in practical biomedical applications such as drug delivery.Importantly,the desired transport efficiency varies depending on the specific application.For instance,while a more rapid transport might be crucial for lymph-node-targeted drug delivery,certain applications requiring a slower release of active components could benefit from the reduced transport efficiency observed with increased particle repulsion or larger intercellular gaps.

Homogeneous PLGA-lipid nanoparticle as a promising oral vaccine delivery system for ovalbumin

In this study,a polymeric lipid nanoparticle(NP)(simplified as Lipid NP)was reported as a promising oral vaccine delivery system.The Lipid NPs composed of a hydrophobic polymeric poly(D,L-lactide-co-glycolide)(PLGA)core and a surface coating of lipid monolayer.Membrane emulsification technique was used to obtain uniform-sized Lipid NPs.Ovalbumin(OVA)was used as a model vaccine.Compared with the pure PLGA NPs,the Lipid NPs achieved higher loading capacity(LC)and entrapment efficiency(EE)for the encapsulated OVA.An in vitro oral release profile showed that the OVA-Lipid NPs were with lower initial burst and could protect the loaded OVA from the harsh gastrointestinal(GI)environment for a long time.In addition,a human microfold cell(M-cell)transcytotic assay demonstrated that due to a lipid layer structure on the particle surface,the Lipid NPs showed higher affinity to the M-cells.Since the M-cell in the intestinal epithelium played an important role in particle transportation as well as intimately associated with the underlying immune cells,the OVA-Lipid NPs effectively induced mucosal and humoral immune responses.

Concepts, processing, and recent developments in encapsulating essential oils

By the virtue of their olfactory,physicochemical,and biological characteristics,essential oils(EOs)have drawn wide attention as additives in daily chemicals like perfume or personal care products.Nevertheless,they are physicochemically unstable and susceptible to degradation or loss.Microencapsulation offers a feasible strategy to stabilize and prolong release of EO.This review summarizes the recognized benefits and functional properties of various preparation and characterization methods,wherein innovative fabrication strategies and their formation mechanisms are especially emphasized.Progress in combining detecting/measuring technologies with kinetic modelling are discussed,to give an integral approach of controlling the dynamic release of encapsulated EOs.Moreover,new development trends of EOs capsules are also highlighted.

Molecular dynamics simulations of ovalbumin adsorption at squalene/water interface

The adsorption of protein molecules to oil/water(O/W)interface is of critical importance for the product design in a wide range of technologies and industries such as biotechnology,food industry and pharmaceutical industry.In this work,with ovalbumin(OVA)as the model protein,the adsorption conformations at the O/W interface and the adsorption stability have been systematically studied via multiple simulation methods,including all-atom molecular dynamic(AAMD)simulations,coarse-grained molecular dynamic(CGMD)simulations and enhanced sampling methods.The computational results of AAMD and CGMD show that the hydrophobic tail of OVA tends to be folded under long time relaxation in aqueous phase,and multiple adsorption conformations can exist at the interface due to heterogeneous interactions raising from oil and water respectively.To further study the adsorption sites of the protein,the adsorption kinetics of OVA at the O/W interface is simulated using metadynamics method combined with CGMD simulations,and the result suggests the existence of multiple adsorption conformations of OVA at interface with the head-on conformation as the most stable one.In all,this work focuses on the adsorption behaviors of OVA at squalene/water interface,and provides a theoretical basis for further functionalization of the proteins in emulsion-based products and engineering.

A two-pronged strategy utilizing exosomes extracted from antigenpresenting cells to combat hepatitis B

Chronic hepatitis B(CHB)is consistently challenging to conquer with numerous complications and fatalities.Despite the effectiveness of antiviral therapies in suppressing hepatitis B virus(HBV)replication,there is an urgent need for novel and more effective treatment modalities.Current strategies predominantly emphasize immune activation but still face challenges in sufficiently eliciting T cell responses.Taking into account the targeted delivery of nanoparticles to the liver and spleen via intravenous injection,we have proposed a dual-pronged therapeutic strategy based on antigen-presenting cells(APCs)-derived exosomes.Specifically,exosomes targeted to the spleen can activate specific immune responses,while those targeted to the liver can modulate or reverse the liver’s immunosuppressive microenvironment.After immunization,exosome formulations exhibit the remarkable ability to effectively activate APCs,thereby triggering the proliferation of CD8^(+)T cells.Simultaneously,they also play an immunoregulatory role by converting M2 macrophages into M1 macrophages.This two-pronged therapeutic strategy precisely addresses the issues of T cell dysfunction and immune suppression,both characteristic features of CHB patients.When combined with Aluminum(Alum)-adjuvanted vaccine,these exosome formulations not only demonstrate a high level of cellular immune response but also secrete specific antibodies comparable to those induced by Alum adjuvant.This combined approach effectively enhances both cellular and humoral immunity,offering a promising avenue for the development of therapeutic hepatitis B vaccines based on exosome formulations.

Exploration and functionalization of M1-macrophage extracellular vesicles for effective accumulation in glioblastoma and strong synergistic therapeutic effects

Glioblastoma multiforme(GBM)is a highly aggressive brain tumor with an extremely low survival rate.New and effective approaches for treatment are therefore urgently needed.Here,we successfully developed M1-like macrophage-derived extracellular vesicles(M1EVs)that overcome multiple challenges via guidance from two macrophage-related observations in clinical specimens from GBM patients:enrichment of M2 macrophages in GBM;and origination of a majority of infiltrating macrophage from peripheral blood.To maximize the synergistic effect,we further functionalized the membranes of M1EVs with two hydrophobic agents(the chemical excitation source CPPO(C)and the photosensitizer Ce6(C))and loaded the hydrophilic hypoxiaactivated prodrug AQ4N(A)into the inner core of the M1EVs.After intravenous injection,the inherent nature of M1-derived extracellular vesicles CCA-M1EVs allowed for blood-brain barrier penetration,and modulated the immunosuppressive tumor microenvironment via M2-to-M1 polarization,which increased hydrogen peroxide(H_(2)O_(2))levels.Furthermore,the reaction between H_(2)O_(2) and CPPO produced chemical energy,which could be used for Ce6 activation to generate large amounts of reactive oxygen species to achieve chemiexcited photodynamic therapy(CDT).As this reaction consumed oxygen,the aggravation of tumor hypoxia also led to the conversion of non-toxic AQ4N into toxic AQ4 for chemotherapy.Therefore,CCA-M1EVs achieved synergistic immunomodulation,CDT,and hypoxia-activated chemotherapy in GBM to exert a potent therapeutic effect.Finally,we demonstrated the excellent effect of CCA-M1EVs against GBM in cell-derived xenograft and patient-derived xenograft models,underscoring the strong potential of our highly flexible M1EVs system to support multi-modal therapies for difficult-to-treat GBM.

Surface charge of PLA microparticles in regulation of antigen loading,macrophage phagocytosis and activation,and immune effects in vitro

The use of microparticles（MPs） as adjuvants has attracted increasing interest in vaccine delivery systems.Many physiochemical characteristics of MPs including hydrodynamic size,surface properties,and morphology can regulate the immune response.Surface charge is an important characteristic of MPs,but how it affects their adjuvanticity remains unknown.In this study,we prepared uniform-sized polylactide MPs coated with various polymers of different positive charge,and investigated how the surface charge affected antigen loading and macrophage phagocytosis and activation in vitro.A higher surface charge greatly enhanced antigen loading and antigen internalization into macrophages,promoted the expression of MHC 11 and CD80,and increased the secretion level of TNF-a.Taken together,these results indicated that surface charge was an important parameter for improving the adjuvanticity of MPs.

RIGID GIGAPOROUS CHROMATOGRAPHIC MEDIA AND THEIR POTENTIAL IMPACT ON DOWNSTREAM PROCESSING

More and more biomolecules are being produced by the biotechnology industry for applications ranging from medicine and food to engineering materials. Liquid chromatography plays a center-stage role in a typical downstream process producing biomolecules such as recombinant proteins. Rigid gigaporous media are porous particles possessing large transecting through-pores with a pore-to-particle diameter ratio of dpore/dparticle〉 0.01. They allow convective flow in the large through-pores, while the smaller diffusion-pores （typically several hundred angstroms in size） supply the needed surface areas. Because of the transecting gigapores, a portion of the mobile phase flows through the pores in addition to fluid flow in the interstitial spaces between the particles in a packed-bed column. This considerably lowers the operating column pressure drop. This lower pressure drop makes axial-direction scale-up of chromatographic columns possible to avoid pancake columns that invariably degrade separation resolution. The large gigapores also make the binding sites on the diffusion pore surfaces more accessible, thus increasing the loading capacity of large protein molecules that can be hindered sterically if only diffusion pores are present. This work discusses the development of rigid gigaporous media and their potential impact on the design of multi-stage downstream process from the angle of multi-scale analysis.

Formation of biomimetic hierarchical nanostructure in homopolymers and block copolymer ternary blend particles

In order to mimic hierarchical nanostructures in nature,particles of polymer blends consisting of poly(4-butyltriphenylamine)(PBTPA),poly(methyl methacrylate)(PMMA)and PBTPA-block-PMMA were fabricated by a solvent evaporation method.Effects of the molecular weight and the chemical composition of PBTPA-b-PMMA,molecular weights of homopolymers,and the composition of the blend on the morphology were investigated.The polymer blend particle consisting of PBTPA and PMMA homopolymers exhibited thermodynamically favored core-shell structure,in which more hydrophilic PMMA-shell surrounded PBTPA-core.The addition of 10 wt%of PBTPA-b-PMMA caused the morphological transition from core-shell toJanus or inversed core-shell,in which PBTPA-shell surrounded PMMA-core,depending on the molecular weight of PBTPA segment in PBTPA-b-PMMA.When the molecular weight of PMMA segment was higher than that of PMMA homopolymer,watermelon-like particles in which small PBTPA domain less than 80 nm dispersed in the PMMA domain surrounded by PBTPA shell were observed.As the ratio of PBTPA-b-PMMA increased,the interface of the macrophase separation became obscure.At 50 wt%of the PBTPA-b-PMMA,only microphase separation was observed.The measurement of interfacial tension by pendant drop method demonstrated that PBTPA-b-PMMA lower the interfacial tension between PBTPA and the aqueous phase to the value similar to that of PMMA with the aqueous phase.

Statistical learning based facial animation

To synthesize real-time and realistic facial animation, we present an effective algorithm which combines image- and geometry-based methods for facial animation simulation. Considering the numerous motion units in the expression coding system, we present a novel simplified motion unit based on the basic facial expression, and construct the corresponding basic action for a head model. As image features are difficult to obtain using the performance driven method, we develop an automatic image feature recognition method based on statistical learning, and an expression image semi-automatic labeling method with rotation invariant face detection, which can improve the accuracy and efficiency of expression feature identification and training. After facial animation redirection, each basic action weight needs to be computed and mapped automatically. We apply the blend shape method to construct and train the corresponding expression database according to each basic action, and adopt the least squares method to compute the corresponding control parameters for facial animation. Moreover, there is a pre-integration of diffuse light distribution and specular light distribution based on the physical method, to improve the plausibility and efficiency of facial rendering. Our work provides a simplification of the facial motion unit, an optimization of the statistical training process and recognition process for facial animation, solves the expression parameters, and simulates the subsurface scattering effect in real time. Experimental results indicate that our method is effective and efficient, and suitable for computer animation and interactive applications.

Engineered self-healing single-cavity microcapsules for pulsatile release of drug delivery

A wide range of polymer-based drug delivery systems have been reported for the treatment of variousdiseases.However,the dosing regimen of many drugs,such as stimulator of interferon genes agonists,programmed cell death protein-1 antibodies,and coronavirus disease 2019 vaccines,consists of repeatedintratumoral or intramuscular injections.These repeated administrations may lead to poor adherence,thus resulting in compromised therapeutic outcomes and increased financial burden.Here,we developed a multidose drug delivery platform by engineering polylactic-co-glycolic acid(PLGA)with differentmolecular weights into self-healing single-cavity microcapsules(SSM).This approach showed a flexiblecollocation strategy to achieve customized pulsatile drug release and was fully degradable with goodsafety.Notably,this single-injection delivery system contains only PLGA,holding great promise forclinical translation.

Inside-out assembly of viral antigens for the enhanced vaccination

Current attempts in vaccine delivery systems concentrate on replicating the natural dissemination of live pathogens,but neglect that pathogens evolve to evade the immune system rather than to provoke it.In the case of enveloped RNA viruses,it is the natural dissemination of nucleocapsid protein(NP,core antigen)and surface antigen that delays NP exposure to immune surveillance.Here,we report a multi-layered aluminum hydroxide-stabilized emulsion(MASE)to dictate the delivery sequence of the antigens.In this manner,the receptor-binding domain(RBD,surface antigen)of the spike protein was trapped inside the nanocavity,while NP was absorbed on the outside of the droplets,enabling the burst release of NP before RBD.Compared with the natural packaging strategy,the inside-out strategy induced potent type I interferon-mediated innate immune responses and triggered an immune-potentiated environment in advance,which subsequently boosted CD40+DC activations and the engagement of the lymph nodes.In both H1N1 influenza and SARS-CoV-2 vaccines,rMASE significantly increased antigen-specific antibody secretion,memory T cell engagement,and Th1-biased immune response,which diminished viral loads after lethal challenge.By simply reversing the delivery sequence of the surface antigen and core antigen,the inside-out strategy may offer major implications for enhanced vaccinations against the enveloped RNA virus.

Advances in Delivering Oxidative Modulators for Disease Therapy

Oxidation modulators regarding antioxidants and reactive oxygen species(ROS)inducers have been used for the treatment of many diseases.However,a systematic review that refers to delivery system for divergent modulation of oxidative level within the biomedical scope is lacking.

核糖核酸酶A的错流超滤复性

针对重组蛋白高表达形成的包涵体,基于中空纤维膜的错流超滤复性具有较大的应用潜力。为研究不同条件对基于中空纤维膜的错流超滤复性的影响,以核糖核酸酶A(RNase A)为例,以复性过程的活性收率和质量收率作为考察指标,设计了RNase A复性初始浓度(A)、跨膜压力(B)、循环流速(C)的3因素3水平正交实验。结果表明,错流超滤复性过程中,以上复性条件对RNase A的质量收率基本没有影响,对RNase A的活性收率具有显著影响,其较优组合为A1B1C2,即RNase A复性初始浓度为0.3 mg/mL、跨膜压力34.0 kPa、循环流速935 cm/min。在以上复性条件下,RNase A的活性收率可达92.31%,质量收率为77.56%。

基于纳米氢氧化铝颗粒的Pickering乳液制备

以异丙醇铝为原料,采用醇盐水解-水热法制备勃姆石型纳米氢氧化铝颗粒,优化制备条件;以所制颗粒为稳定剂、角鲨烯为油相,通过超声破碎法制备Pickering乳液,考察了颗粒浓度、水相成分、超声时间及功率对Pickering乳液粒径及稳定性的影响。结果表明,水热温度200℃、水热时间2 h条件下,可制得结晶度高且均一的勃姆石型纳米氢氧化铝颗粒,平均粒径为55.70±9.20 nm,多分散性指数(PDI)为0.187±0.011;所制Pickering乳液平均粒径为1 870±55 nm,PDI=0.120±0.010,可在室温下稳定储存120 d以上,且生物相容性良好,有望应用于生物医药领域。

新型电荷型纳米盘的可控制备及其与细胞色素P450的结合性能

分别采用氮气吹干法和旋转蒸发法制备由磷脂和膜支架蛋白组成的电荷型纳米盘,用凝胶过滤色谱对其尺寸分级,分析了其性能,考察了其与肝微粒体细胞色素P450的结合能力。结果表明,纳米盘外观澄清透明,微观呈圆盘状,平均直径10nm,在p H 7.4下Zeta电位为-19.86 m V;肝微粒体破碎液与纳米盘能很好结合,CO差示光谱在450 nm出现明显吸收峰,细胞色素P450含量为0.10 nmol/mg,比活比未经纳米盘处理时提高13.0倍,较传统方法提升1.5倍,且操作时间由数日缩短至数小时。电荷型纳米盘在结合膜蛋白细胞色素P450的同时,活性保持良好,在膜蛋白研究领域极具应用潜力。

基于疫苗颗粒完整性的硅胶吸附/解吸附纯化重组乙肝表面抗原工艺研究

针对重组汉逊酵母乙肝表面抗原(HBsAg)在传统纯化过程中稳定性差的问题,采用静态光散射、荧光光谱和动态光散射等分析手段,从颗粒完整性角度研究其在不同pH条件下的稳定性变化。以其为指导,采用硅胶吸附/解吸附纯化HBsAg,建立该过程中关键因素的响应面模型,并与疏水层析联用,进一步纯化HBsAg,分析纯化效果以及纯化后疫苗颗粒完整性。采用透射电镜观察纯化后疫苗形貌,用高效分子排阻色谱法(HPSEC)分析颗粒稳定性。结果表明在酸性溶液下,pH接近HBsAg等电点时,抗原颗粒间静电斥力减小,颗粒容易聚集;碱性条件下,抗原颗粒内部疏水基团暴露,造成颗粒解聚。建立响应面模型,以活性收率为响应值时,最佳纯化工艺为吸附pH=7.43,洗脱pH=10.48,洗脱温度55.4℃,此时活性收率最高为39.1%;以纯化倍数为响应值时,吸附pH=7.16,洗脱pH=10.52,洗脱温度55.1℃,此时纯化倍数最高为1.90。进一步对洗脱液进行疏水层析纯化,活性收率为49.73%,颗粒完整性为85.79%,透射电镜观察到抗原颗粒粒径为20~40 nm。与传统疏水层析方法相比,采用硅胶吸附/解吸附与疏水层析联用的纯化方法,疫苗活性收率提高31.99个百分点,颗粒完整性提高20.90个百分点,颗粒稳定性提高22.93个百分点。该研究为高效纯化重组HBsAg及提高疫苗纯化过程的颗粒完整程度等提供新思路。

Recent research and development of PLGA/PLA microspheres/nanoparticles: A review in scientific and industrial aspects

Poly(D,L-lactic-co-glycolic acid)(PLGA)/poly (lactic acid)(PLA) microspheres/nanoparticles are one of the most successful drug delivery systems (DDS) in lab and clinic. Because of good biocompatibility and biodegradability, they can be used in various areas, such as longterm release system, vaccine adjuvant, tissue engineering, etc. There have been 15 products available on the US market, but the system still has many problems during development and manufacturing, such as wide size distribution, drug stability issues, and so on. Recently, many new and modified methods have been developed to overcome the above problems. Some of the methods are easy to scale up, and have been available on the market to achieve pilot scale or even industrial production scale. Furthermore, the relevant FDA guidance on the DDS is still incomplete, especially for abbreviated new drug application. In this review, we present some recent achievement of the PLGA/PLA microspheres/nanoparticles, and discuss some promising manufacturing methods. Finally, we focus on the current FDA guidance on the DDS. The review provides an overview on the development of the system in pharmaceutical industry.

Preparation of double-emulsion-templated microspheres with controllable porous structures by premix membrane emulsification

A scalable and versatile strategy was developed for the fabrication of uniform polymeric microspheres with controllable interconnected porous structures. Uniform water-in-oil-in-water emulsions with linear poly(methyl methacrylate-glycidyl methacrylate) in the oil phase were generated by two-step premix membrane emulsification and used for constructing the microspheres. During the emulsion solidification process, internal water droplets were packed densely together, forming a thin oil film between the internal and external water phases. After solvent diffusion, the thin film can be ruptured and pores can be templated from the internal water droplets to form interconnected porous structures. Membranes with various pore sizes were obtained. The osmotic pressure and Laplace pressure balance were used to control the porosity and pore size precisely. The proposed method enables the fabrication of functional polymeric microspheres with uniform and controllable porous structures and particle sizes. This improves their performance and broadens the scope of their applications, especially in chromatographic separation.

Advances in Uniform Polymer Microspheres and Microcapsules:Preparation and Biomedical Applications

What is the most favorite and original.chemistry developed in your research group?We clarified the,mechanism for obtaining uniform microspheres and microcapsules in 0/W,W/0 and double emulsion systems,which enabled us to develop the technique to a universal technique,successfully,preparing various uniform particles including,hydrophobic,hydrophilic and composite functional particles,and leading to the original systematic studies on biomedical applications including"Synthetic Vaccine".