We prepare ZnO nanoparticles by environmentally friendly synthesis using Cyathea nilgiriensis leaf extract. Various phytochemical constituents are identified through the assessment of ethanolic extract of plant Cyathea nilgiriensis holttum by GC-MS analysis. The formation of ZnO nanoparticles is confirmed by FT-IR, XRD, SEM-EDX, TEM, SAED and PSA analysis. TEM observation reveals that the biosynthesized ZnO nanopowder has a hexagonal structure. The calculated average crystallite size from the high intense plane of (1 0 1) is 29.11 nm. The particle size, determined by TEM analysis, is in good agreement with that obtained by XRD analysis. We confirm the formation of biomolecules in plant extract by FT-IR analysis and propose a possible formation mechanism of ZnO nanoparticles. Disc diffusion method is used for the analyses of antimicrobial activity of ZnO nanoparticles. The synthesized ZnO nanoparticles exhibit antimicrobial effect in disc diffusion experiments. The biosynthesized ZnO nanoparticles display good antibacterial performance against B. subtilis (Gram-positive bacteria) and K. pneumonia (Gram-negative bacteria). Bio-synthesized nanoparticles using green method are found to possess good antimicrobial performance.

Perennial need for bactericides requires cost-effective nanomaterials with strong antibacterial activities even in the absence of external irradiation. Hence, in this work, we have synthesized f-CFT (fluorinated TiO2- doped, glycine-functionalized MWCNTs) and have studied its antibacterial activities. Both gram-negative and gram-positive bacteria were analyzed in the absence of photo-activation. Zone of inhibition of 15 mm for S. aureus, and 11 mm for P. aeruginosa was observed for f-CFT owing to the synergistic bactericidal properties of functionalized MWCNTs, fluorine and nano-TiO2. Anatase phase TiO2 with average crystallite size as 35 nm was observed in XRD. Scanning electron microscopic images showed uniform mixed cubic structures. Hydroxyl groups observed in FT-IR along with the glycine MWCNTs interface aid the inhibition of bacterial growth even in the absence of photo activation. A desired higher gram-positive bacterial inhibition opens new gates for better antibacterial agents.

Polyurethane (PU) nanofibers containing graphene oxide (GO) and Ag doped functionalized reduced graphene oxide (Ag-RGO) were successfully prepared via the electrospinning technique. The uniform distribution of GO sheets along with Ag nanoparticle in the nanofibers was investigated by scanning electron microscopy and the elemental mapping technique. X-ray diffraction and thermal gravimetric analysis verified the presence of GO and Ag in the bicomposite nanofibrous mats. Antibacterial tests against Escherichia coli demonstrated that the addition of GO and Ag-RGO to the PU nanofiber greatly enhanced bactericidal efficiency. Overall, these features of the synthesized nanofibers make them a promising candidate material in the biomedical field for applications such as tissue engineering, wound healing, and drug delivery systems.

목적: 본 연구는 2-fluoro-4-pyridinecarboxylic acid 및 6-fluoropyridine-3-carboxylic acid를 사용하여 친수성 하이드로젤 콘택트렌즈 재질을 중합하고 제조된 친수성 콘택트렌즈의 물리적, 광학적 특성을 분석하여 이들 물질들의 콘택트렌즈 재료로서의 활용도를 알아보았다. 방법: 본 연구는 카르복시산 및 불소로 치환한 피리딘을 2가지 이상 첨가제로 사용하여 친수성 콘택트렌즈의 기본적인 재질인 HEMA(2-hydroxyethyl methacrylate), AA(acrylic acid), MMA(methylme-thacrylate), 개시제인 AIBN(azobisisobutyronitrile), 그리고 교차결합제인 EGDMA(ethylene glycol dimethacrylate)를 사용하여 공중합하였다. 결과: 생성된 고분자의 물리적 특성을 측정한 결과, 굴절률 1.4348-1.4300, 함수율 33.69~35.84%, 가시광선 투과율 89.6~90.8%, 인장강도 0.2292-0.3344kgf 그리고 접촉각의 경우 76.05°~50.95°의 분포를 나타내었다. 또한 황색포도상구균에 대한 항균실험 결과 2-fluoro-4-pyridinecarboxylic acid 및 6- fluoropyridine-3-carboxylic acid를 5% 첨가했을 때 항균효과가 다소 있는 것으로 나타났다. 결 론: 본 실험 결과, 2-fluoro-4-pyridinecarboxylic acid 및 6-fluoropyridine-3-carboxylic acid를 첨가하여 제조된 친수성 콘택트렌즈는 기본적인 콘택트렌즈 물성을 만족하였으며 우수한 습윤성과 항균성 및 자외선 차단 콘택트렌즈로 활용될 수 있을 것으로 판단된다.