Period four metal nanoparticles on the inhibition of biofouling

Abstract

Biofilms present operational problems to a variety of industrial areas including but not limited to, medicine, water treatment, sensor sensitivity and shipping. Bacterial adhesion resides as a tiny monolayer and builds-up over time with the production of protective slimes known as extracellular polymeric substances (EPS) forming the 'biofilm'. Infection, inefficiency and diminution of quality are caused by biofilms, which have the potential to be prohibitively expensive to repair. The value of an effective coating that prevents the adhesion of bacteria and subsequent fouling is paramount in preserving sensitivity and longevity of a subjected operational substrate. Polymer and sol-gel (SG) based coatings tender a matrix for the introduction of biocides and antimicrobial agents that offer this prevention. They present a relatively cheap and optically clear platform that can then be doped with the antimicrobial agent. This proves useful in transferring across a range of industries that may require a transparent function to the coating. Nanoparticles offer a means of new line research in combating biofouling and biocorrosion with interest stemming from silver metal nanoparticles (MNPs) that already offer antimicrobial property. The aim of this work is to investigate period four metal nanoparticles for any antimicrobial potential they offer, in the prevention of fouling in the early stages. The research presented herein uses a range of period four MNPs synthesised through an adapted polyol reduction, which have then been doped into SG coatings and tested for their efficacy in preventing levels of biofouling. After a 7-day freshwater study results showed that MNPs prevent levels of biofouling upto 125% compared to the SG blank. The work uses bacterial enumeration, minimum inhibitory concentration (MIC), surface characterisation and slime and biomass analysis to complete a range of studies in assessing the level of fouling observed on the test substrates.