Antibacterial Activity of Biologically Synthesized Nanosilver against Drug-Resistant Bacterial Pathogens

ABSTRACT

Biosynthesis of nanoparticles by plant extracts is currently under exploration. Biological methods are a good competent to chemical procedures, which are environmentally friendly and convenient. We report the use of new plant extract of Cuscuta reflexa in the extracellular biosynthesis of silver nanoparticles. Bioactive silver nanoparticle synthesis was achieved by reacting the biomass of C. reflexa with aqueous solutions of silver nitrate (AgNO₃) at ambient temperature. The formation of silver nanoparticles was confirmed by ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction patterns, and transmission electron microscopy (TEM). In the present study we report the excellent antibacterial activity of silver nanoparticle (with C. reflexa extract) against gram-positive and gram-negative multi-drug-resistant (MDR) bacterial strains using a zone of inhibition method. Scanning electron microscopy (SEM) imaging studies revealed that silver nanoparticles physically damaged the bacterial cell and ultimately led to cell death.

KEYWORDS:

• Biosynthesis
• Cuscuta reflexa
• nanosilver
• antibacterial
• drug resistance

Acknowledgments

The authors gratefully acknowledge financial support of this research from the Indian Council of Medical Research (ICMR), New Delhi, India, under IRIS (2009–08130). We are also grateful to Dr. N. K. Saini, Dr. N. K. Juyal, and Dr. Samay Singh, WIHG, Dehradun, for providing XRD and SEM facilities.