Microwave-Assisted Green Synthesis of Small Gold Nanoparticles Using Aqueous Garlic (Allium sativum) Extract: Their Application as Antibiotic Carriers

ABSTRACT

This article establishes a rapid, microwave-assisted green synthetic method for the production of gold nanoparticles (AuNPs) using garlic extract as a reducing and stabilizing agent and seeks their application as antibiotic carriers. The appearance, crystalline nature, size, and shape of nanoparticles are understood by different physical techniques like UV-vis spectroscopy, transmission electron microscopy, and X-ray diffraction. The AuNPs of size varying from 1.8 ± 0.85 nm to 23.2 ± 4.1 nm were synthesized successfully by varying the power of microwave irradiation. Further, AuNPs (of size 23.2 ± 4.1 nm) were functionalized with ciprofloxacin (cfH), a broad-spectrum antibiotic. A red shift in absorption and emission maxima with decreased intensity suggested successful binding of cfH to AuNPs. AuNPs-conjugated cfH (cfH@AuNPs) were found to have better antibacterial activities in terms of zone of inhibition compared to free cfH against the tested bacterial strains.

KEYWORDS:

• gold nanoparticles
• green synthesis
• microwave irradiation
• ciprofloxacin
• antibiotic delivery

Acknowledgments

The authors thank Dr. T. Mukherjee, Director, and Dr. S.V. Narasimhan, former Associate Director, Chemistry Group, BARC, for their constant support and encouragement. The Sophisticated Analytical Instrument Facility at IIT Bombay is acknowledged for TEM analysis.