Biodegradable metals have attracted considerable attentions in recent years. Besides the early launched biodegradable Mg and Fe metals, Zn, an essential element with osteogenic potential of human body, is regarded and studied as a new kind of potential biodegradable metal quite recently. Unfortunately, pure Zn is soft, brittle and has low mechanical strength in the practice, which needs further improvement in order to meet the clinical requirements. On the other hand, the widely used industrial Zn-based alloys usually contain biotoxic elements (for instance, ZA series contain toxic Al elements up to 40 wt.%), which subsequently bring up biosafety concerns. In the present work, novel Zn-1X binary alloys, with the addition of nutrition elements Mg, Ca and Sr were designed (cast, rolled and extruded Zn-1Mg, Zn-1Ca and Zn-1Sr). Their microstructure and mechanical property, degradation and in vitro and in vivo biocompatibility were studied systematically. The results demonstrated that the Zn-1X (Mg, Ca and Sr) alloys have profoundly modified the mechanical properties and biocompatibility of pure Zn. Zn-1X (Mg, Ca and Sr) alloys showed great potential for use in a new generation of biodegradable implants, opening up a new avenue in the area of biodegradable metals.

Surface modification with polyethylene glycol (PEG; PEGylation) is a widely used technique to improve nanoparticle (NP) stability, biocompatibility, and biodistribution profiles. In particular, PEGylation of silica surfaces and coatings plays a pivotal role across various classes of NPs. Despite the use of numerous protocols there is limited fundamental understanding of the mechanisms of these processes for NPs. Here, after reaction optimization for particle stability, we employ fluorescence correlation and crosscorrelation spectroscopy (FCS, FCCS) on ultrasmall (<10 nm) fluorescent silica nanoparticles (SNPs) in water as a test bed. We show unexpected fast reaction kinetics in successful PEGylation observed even at nanomolar concentrations and attributed this to instant noncovalent adsorption of PEG molecules to the SNP surface preceding covalent attachment. Further studies of various reaction conditions enable the elucidation of process design criteria for NP PEGylation and surface modification with functional ligands, which may be applicable to a broad range of NPs thereby accelerating progress in fields ranging from biosensing to nanomedicine.

Inspired by mussel-adhesion phenomena in nature, we present a simple, mild and green method to prepare polystyrene/Ag (PS/Ag) nanocomposite particles with enhanced antibacterial activities. In this approach, monodisperse polystyrene particles are used as template spheres, which are then coated with polydopamine (PDA) through the self-polymerization of dopamine in a weakly alkaline aqueous environment (pH ¼ 8.5). Silver precursor-[Ag(NH 3 ) 2 ] + ions are added and absorbed onto the surfaces of the PS/PDA composite spheres by the active catechol and amine groups of the polydopamine coating. Meanwhile, these adsorbed [Ag(NH 3 ) 2 ] + ions are in situ reduced into metallic silver nanoparticles by the "bridge" of the polydopamine coating, and the formed Ag nanoparticles are home positioned. As polydopamine is an environmentally friendly reagent with abilities as a universal adhesive to any surface and as a mild reductant for noble metal salts, because of its abundant active catechol and amine groups, neither additional reducing and toxic reagents nor special surface modifications of the template are needed in this procedure. Moreover, preliminary antibacterial assays indicate that these PS/Ag nanocomposite particles show enhanced antibacterial activities against Escherichia coli (Gram-negative bacteria) and Staphylococcus aureus (Gram-positive bacteria), while they do not show significant in vitro cytotoxicity against HEK293T human embryonic kidney cells. These results suggest that these PS/Ag nanocomposite particles could be promising antibacterial materials for future biomedical applications.

Multi-stimuli responsive polymer microcapsules are attracting much interest owing to their more and tuanble functionalities, but it still remains a great challenge to develop facile and cost-efficient strategies for fabrication of these microcapsules. In this study, we report a simple and facile method to synthesize pH and UV dual-responsive microcapsules by UV-initiated polymerization of Pickering emulsions stabilized with SiO 2 and TiO 2 nanoparticles. Because the UV-initiated polymerization is gentle and fast, the asobtained microcapsules can encapsulate as high as 30 wt% of hydrophobic compound based on the total mass of the capsules. When these 10 microcapsules are used in waterborne coatings, these coatings exhibit not only quick responses to pH and UV stimuli, but also very good self-repairing performance. Journal Name, [year], [vol], 00-00 | 5 65When treated in UV accelerated weathering tester for 408 h, the WCA of D0.75-coating increased to 154.7°, owing to the slow release of FAS12 molecules from D0.75-capsules. And this superhydrophobic surface could hold more than 960 h in accelerated weathering tester (Fig. 8b), which is enough for 70

Natural product podophyllotoxin exhibited superior broad spectrum antitumor and antiviral activity. Over past 30 years, scientists devoted continuous efforts to develop druggability strategies and discover new podophyllotoxin-derived drugs.