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.

Abstract
1. 서 론
2. 실험방법
3. 결과 및 고찰
    3.1 합성한 ZnO 나노분말의 형태, 크기 및 구조
    3.2 ZnO 나노분말의 항균 활성
4. 결 론
References

• 홍순익(충남대학교 신소재공학과) | Sun Ig Hong (Department of Nanomaterials Engineering, Chungnam National University) Corresponding author
• 송재숙(충남대학교 신소재공학과) | Jae Sook Song (Department of Nanomaterials Engineering, Chungnam National University)
• Joghee Suresh(인도 Sri Ramakrishna 공과대학)