Applied Mechanics and Materials Vol. 749

Abstract: Novel hybrids, comprised of a biologically active protein molecule core, coated with a thin outer layer of porous metallic silver, were developed in our lab. By the conjugation of silver reducing polymer to the surface of soluble, molecular, biologically active protein molecules and subsequent addition of silver salt, electroless silver deposition, culminating in thin porous metallic coating, was directed to the surface of the protein molecules. The silver-protein hybrids thus obtained, presenting novel nanoparticles several nanometers in size, retained their solubility and biological activity.The silver coating combined with the retained biological activity of its protein core, paved the way to a series of biomedical applications of these hybrids including "wiring" of the active site of oxido-reductase enzyme to electrodes, imaging of the presence of targeted ligands displayed on cancer cell surface and antimicrobial enzymatically attenuated release of silver ions.In this presentation we shall overview the technology of protein-silver hybrid's fabrication and analytical applications of silver-glucose oxidase and silver-Avidin hybrids, followed by feasibility demonstration of using silver-glucose oxidase hybrid as novel antibacterial and antifungal agent.

Abstract: In this study, we developed the porous alginate (AL) scaffolds with modified pores size and distributions to actively control tissue regeneration. An addition of 5 and 10% (v/v) butanol to AL solution was effective to control pores structures of AL scaffolds. Especially, increased amount of butanol induced that proportion of smaller pores (size of around 5~10 μm) on AL scaffolds increased. Using swelling kinetics analysis, we confirmed that micro pore modified AL scaffolds show faster swelling rate than pristine scaffolds. During in vitro study, the enhanced viability and proliferation of human dermal fibroblasts (HDFs) were observed by the pore size and distribution from micro pore modified AL scaffolds. However, AL scaffolds added 10 % butanol with excessive proportion of smaller pores induced the decreased viability of HDFs for 7 days. From our results, AL scaffolds with modified pores structures represent a potential implants to control biological in vitro and in vivo functions in a variety of tissue engineering.

Abstract: Structural, optical and photocatalytic properties of ZnO powders prepared by a precipitation method were systematically investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis diffuse reflectance measurement and UV-Vis absorbance measurement. The antibacterial activity was tested by a broth microdilution method. All calcined ZnO powders exhibited a hexagonal wurtzite structure. The ZnO powders formed various shapes depending upon the concentration of n-propylamine used. The E_g value of ZnO powders depended upon defect concentration. The photocatalytic property of ZnO powders depended on the particle shape and defect concentration. The best photocatalytic efficiency of 100% was observed from the ZnO powders prepared at R = 2 after irradiating by the blacklight for 90 min. All ZnO powders can damage only S. aureus and the agglomerated sheet-like ZnO powders prepared at R = 2 showed the best antibacterial property with a MIC value of 1.5625 mg/mL.