抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

https://cyberleninka.org/article/n/933162.pdf

Hydrogels in drug delivery: progress and challenges

Over the past few decades, researchers have established artificial enzymes as highly stable and low-cost alternatives to natural enzymes in a wide range of applications. A variety of materials including cyclodextrins, metal complexes, porphyrins, polymers, dendrimers and biomolecules have been extensively explored to mimic the structures and functions of naturally occurring enzymes. Recently, some nanomaterials have been found to exhibit unexpected enzyme-like activities, and great advances have been made in this area due to the tremendous progress in nano-research and the unique characteristics of nanomaterials. To highlight the progress in the field of nanomaterial-based artificial enzymes (nanozymes), this review discusses various nanomaterials that have been explored to mimic different kinds of enzymes. We cover their kinetics, mechanisms and applications in numerous fields, from biosensing and immunoassays, to stem cell growth and pollutant removal. We also summarize several approaches to tune the activities of nanozymes. Finally, we make comparisons between nanozymes and other catalytic materials (other artificial enzymes, natural enzymes, organic catalysts and nanomaterial-based catalysts) and address the current challenges and future directions (302 references).

Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes

PLGA-based nanoparticles: An overview of biomedical applications

We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.

/pdf/science-and-technology-roadmap-for-graphene-related-two-4q9m7czlkc.pdf

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

Recent advances in platelet engineering for anti-cancer therapies

Cationic liposome based siRNA delivery system has improved the efficiencies of siRNA. However, cationic liposomes are prone to be rapidly cleared by the reticuloendothelial system (RES). Although modification of cationic liposomes with polyethylene glycol (PEG) could prolong circulation lifetime, PEG significantly inhibits siRNA entrapment efficiency, cellular uptake and endosomal/lysosomal escape process, resulting in low gene silencing efficiency of siRNA. In this study, we report the synthesis of zwitterionic polycarboxybetaine (PCB) based distearoyl phosphoethanolamine-polycarboxybetaine (DSPE-PCB) lipid for cationic liposome modification. The DSPE-PCB20 cationic liposome/siRNA complexes (lipoplexes) show an excellent stability in serum medium. The siRNA encapsulation efficiency of DSPE-PCB20 lipoplexes could reach 92% at N/P ratio of 20/1, but only 73% for DSPE-PEG lipoplexes. The zeta potential of DSPE-PCB20 lipoplexes is 8.19±0.53mV at pH 7.4, and increases to 24.6±0.87mV when the pH value is decreased to 4.5, which promotes the endosomal/lysosomal escape of siRNA. The DSPE-PCB20 modification could enhance the silencing efficiency of siRNA by approximately 20% over the DSPE-PEG 2000 lipoplexes at the same N/P ratio in vitro. Furthermore, DSPE-PCB20 lipoplexes could efficiently mediate the down-regulation of Apolipoprotein B (ApoB) mRNA in the liver and consequently decrease the total cholesterol in the serum in vivo, suggesting therapeutic potentials for siRNA delivery in hypercholesterolemia-related diseases.

Enhanced endosomal/lysosomal escape by distearoyl phosphoethanolamine-polycarboxybetaine lipid for systemic delivery of siRNA / J. Control. Release

We here report the facile fabrication of inverse core–shell and Janus structured particles consisting of poly(4-butyltriphenylamine) (PBTPA) and poly(methyl methacrylate) (PMMA) via a solvent evaporation from solution droplets of a polymer blend dispersed in an aqueous phase. Janus structured composite particles in which the PBTPA domain was partially coated by the PMMA domain were obtained using poly(vinyl alcohol) (PVA) as a suspension stabilizer. On the other hand, when sodium dodecyl sulfate (SDS) was added as a surfactant together with PVA, “inverse core–shell” particles in which the PMMA core was covered by the PBTPA shell were formed as well as Janus particles. TEM observation showed that the PMMA core was located at the center of the sphere and PBTPA layer has uniform thickness in inverse core–shell particles. The increase of the composition of PBTPA or the concentration of SDS increased the ratio of the inverse core–shell particles to the Janus ones.

Fabrication of inverse core–shell and Janus-structured microspheres of blends of poly(4-butyltriphenylamine) and poly(methyl methacrylate)

On p. 3153, Guang-Hui Ma and co-workers report on the development of autofluorescent chitosan microspheres with tunable color based on different crosslinking reagents and further chemical modification. The fluorescent intensity can also be controlled by the particle size and crosslinking degree. The autofluorescent microspheres may be useful in fluorescence assays as bright, inexpensive, and stable probes for qualitative and quantitative studies of biological interactions and drug delivery.



Fluorescent microspheres are widely used as biological tracers. In this study, uniformly sized chitosan microspheres crosslinked with glutaraldehyde (CG microspheres) and formaldehyde (CF microspheres) are successfully prepared by the Shirasu Porous Glass (SPG) membrane emulsification technique. Selectively reduced CG microspheres (SRCG microspheres) are obtained by NaBH4 reduction. These chitosan microspheres are found to exhibit fluorescent properties without conjugation to any fluorescent agent. The fluorescence color varies with different crosslinkers and can be modulated by further chemical reduction, whereas the fluorescence intensity can be controlled by tuning the particle size and degree of crosslinking. The autofluorescence of the microspheres is applied to study the phagocytosis of HepG2 cells using the microspheres as novel tracers. Quantitative and qualitative evaluations show that these chitosan microspheres serve as bright, inert, durable, and extremely photostable tracers.

Cover Picture: Preparation and Application of Novel Microspheres Possessing Autofluorescent Properties (Adv. Funct. Mater. 16/2007)

The invention discloses the microspheres comprising the following structure in the composition thereof and the uses as tracers and fluorescent standard calibration products. wherein, groups A, B and C are linked to hydrocarbon chain , and at least one of A, B and C has the structure of —N═R—, in which R is a residue after the reaction of an aldehyde-type cross-linking substance, and the others of A, B and C are —NH 2 structure. The microspheres comprising the above structure have an obvious phenomenon of self-fluorescence, and the fluorescence output of each microsphere is significantly larger than the fluorescence outputted by the microsphere embedded with fluorescent substances. The microspheres have toleration to light-bleach and the dependency on other environments without modifying the surface property of the microspheres themselves. The invention further discloses the preparation method of the above fluorescent microspheres. The fluorescence color of the fluorescent microspheres can be adjusted by selecting different aldehyde-type substances or the combinations thereof, and the fluorescence intensity of the microspheres can be controlled not only by the addition of the aldehyde-type substances and the time of the cross-linking reaction, but also by adjusting the size of the particle diameters of the microspheres.

Guanghui Ma

Papers

Recent advances in platelet engineering for anti-cancer therapies

Enhanced endosomal/lysosomal escape by distearoyl phosphoethanolamine-polycarboxybetaine lipid for systemic delivery of siRNA / J. Control. Release

Fabrication of inverse core–shell and Janus-structured microspheres of blends of poly(4-butyltriphenylamine) and poly(methyl methacrylate)

Cover Picture: Preparation and Application of Novel Microspheres Possessing Autofluorescent Properties (Adv. Funct. Mater. 16/2007)

Fluorescent microspheres, the preparation method and uses thereof