ORIGINAL PAPER One Pot Synthesis of Gentamicin Conjugated Gold Nanoparticles as an Efficient Antibacterial Agent Deepak Sharma 1 • Abhishek Chaudhary 1 Received: 3 March 2020 Ó Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract In the present study, we report a simple, robust, and eco-friendly one pot synthesis of gentamicin conjugated gold nanoparticles (G-GNPs), where gentamicin behaves dually as a reducing as well as a stabilizing agent. The resultant nanoparticles were characterized through different microscopic and spectroscopic techniques and found to be almost spherical in shape with hydrodynamic diameter of * 15 nm along with excellent stability. The antibacterial potential was evaluated by well diffusion assay and showed that G-GNPs effectively inhibit the growth of gram-positive and gram- negative bacteria viz. Escherichia coli DH5a, Escherichia coli ATCC 25922 and Staphylococcus aureus MTCC 3160 (p \ 0.05). Results also revealed that G-GNPs exhibit excellent antibacterial activity as compared with pure gentamicin, interestingly G-GNPs also showed excellent activity against gentamicin resistant Escherichia fergusonii ATCC 35469. A sustained release of gentamicin molecules from nanoparticles was observed. Furthermore, when we tested the effect of G-GNPs on mouse myoblast C2C12 cell line, G-GNPs exhibited minimal cytotoxicity. Consequently, the developed G-GNPs can be considered as safe based on minimal cytotoxicity of G-GNPs, and hold a great potential against gram- positive, gram-negative and drug resistance bacteria. Keywords Gentamicin Á Gold nanoparticles Á Antibacterial effect Á Drug release Á Cytotoxicity Introduction Antibiotic resistance in pathogenic microorganisms is one of the potential threats to modern medicine that must be addressed to benefit mankind globally. Advance resistance Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10876-020-01864-x) con- tains supplementary material, which is available to autho- rized users. & Abhishek Chaudhary abhishekcbt@gmail.com; abhishek.chaudhary@juit.ac.in 1 Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Solan, Waknaghat, Himachal Pradesh 173234, India 123 Journal of Cluster Science https://doi.org/10.1007/s10876-020-01864-x