Combating Biofilm Formation by Modulating Iron Concentration, using Nanoparticles and Plant Extracts

Abstract: Biofilm formation often has detrimental effects from clinical and industrial perspectives. They are found to be resistant to antibiotics, detergents, etc., causing their treatment and cure to be onerous. Therefore, it becomes a necessity to develop novel methods to inhibit it. Iron is an essential regulator of bacterial biofilm formation. Studies suggest that by modulating iron concentration using either iron-chelating substances or iron salts, biofilm inhibition can be achieved depending on the mechanism of biofilm formation. This approach inhibits the expression of several genes responsible for adherence and colonization of bacteria. The use of nanoparticles is gaining rapid interest for biofilm inhibition. The ability of nanoparticles to act as antibacterial agents depends on their surface-to-mass ratio. Owing to their small size, certain metal nanoparticles can penetrate the EPS and inhibit bacterial adhesion and biofilm formation. Nanoparticles (NP) bring about cell lysis by interacting with cell membranes or producing Reactive Oxygen Species (ROS). Owing to the mechanical, thermal, or physiochemical properties of nanocomposite material, it is also studied for biofilm inhibition in various organisms. A widely appreciated method of NP synthesis is green synthesis, which makes use of plant extracts and microorganisms. Interestingly, plant extracts inherently are known to possess antimicrobial and anti-biofilm effects owing to their bioactive compounds. Plants synthesize secondary metabolites such as steroids, terpenoids, alkaloids, quinones, tannins, flavonoids, etc., for their defense, pollination, flavor, etc. Plant extracts made using appropriate solvents can be used to inhibit biofilm formed on various surfaces. They have been known to reduce biofilm by hindering exopolysaccharide formation and quorum sensing. In this review, we aim to describe these potential methods of biofilm inhibition.