Functionalization of Inorganic Nanoparticles to Augment Antimicrobial Efficiency: A Critical Analysis

Background: Nanoparticles (NPs) or nanomaterials being used widely in various fields have occupied prime importance in biomedical sciences, owing to their unique size dependent properties which make them superior to bulk materials. One of the major applications of NPs in biomedical field is their therapeutic application including antimicrobial activity. Objective: It is already well known that certain NPs such as silver, zinc oxide, copper, iron etc. bears significant antimicrobial activity as they release metal ions which subsequently generate reactive oxygen species (ROS), consequently demonstrating potential to be a better alternative to antibiotics and other antimicrobial agents. Although some of these NPs have also been found to be effective against multi-drug resistant (MDR) bacteria and correspondingly preventing the biofilm formation. Still resistance can be developed towards these NPs owing to their repeated exposure. Therefore, it becomes pertinent to probe NPs for their better antimicrobial efficacies by using surface functionalization strategies to enable them to interact with some specific cells in order to augment the antimicrobial response. Results: Thus present review focuses on the mode of action of NPs, their toxicity and colloidal stability, shortcomings of antibiotics and other antimicrobial agents towards MDR bacteria, and possible outcomes of NPs functionalized with different agents. Conclusion: In this review we describe functionalized NPs as an alternative for targeting MDR bacteria, their mode of action and future directions that are necessary to move forward with this approach. Keywords: Nanoparticle functionalization, antimicrobial mechanism, multidrug resistant bacteria, silver ion, antibiotic, carbon nanotubes.