Antibiofilm Properties of Silver and Gold Incorporated PU, PCLm, PC and PMMA Nanocomposites under Two Shear Conditions

Abstract

Silver and gold nanoparticles (of average size ∼20–27 nm) were incorporated in PU (Polyurethane), PCLm (Polycaprolactam), PC (polycarbonate) and PMMA (Polymethylmethaacrylate) by swelling and casting methods under ambient conditions. In the latter method the nanoparticle would be present not only on the surface, but also inside the polymer. These nanoparticles were prepared initially by using a cosolvent, THF. PU and PCLm were dissolved and swollen with THF. PC and PMMA were dissolved in CHCl3 and here the cosolvent, THF, acted as an intermediate between water and CHCl3. FTIR indicated that the interaction between the polymer and the nanoparticle was through the functional group in the polymer. The formation of E.coli biofilm on these nanocomposites under low (in a Drip flow biofilm reactor) and high shear (in a Shaker) conditions indicated that the biofilm growth was higher (twice) in the former than in the latter (ratio of shear force = 15). A positive correlation between the contact angle (of the virgin surface) and the number of colonies, carbohydrate and protein attached on it were observed. Ag nanocomposites exhibited better antibiofilm properties than Au. Bacterial attachment was highest on PC and least on PU nanocomposite. Casting method appeared to be better than swelling method in reducing the attachment (by a factor of 2). Composites reduced growth of organisms by six orders of magnitude, and protein and carbohydrate by 2–5 times. This study indicates that these nanocomposites may be suitable for implant applications.

Critical review on biofilm methods

“…Therefore, this reactor has been extensively used for different assays, e.g. to assess the effect of disinfection strategies and nanocomposites on biofilm control under low shear stress (Buckingham-Meyer et al, 2007;Sawant et al, 2013;Stewart et al, 2001), to mimic indwelling medical devices and evaluate antimicrobial properties (Ammons et al, 2011;Carlson et al, 2008). Limitations of this device include biofilm heterogeneity on the coupons associated with the device hydrodynamic and the low shear stress, low similarity with industrial conditions and the limited number of samples.…”

Polydimethyl siloxane nanocomposites: Their antifouling efficacy in vitro and in marine conditions

“…Tributyltin (TBT)-based antifouling (AF) paints, though extremely effective, have been banned by International Maritime Organization (IMO), since they are very toxic to marine biota (Thomas and Brooks, 2010). Other approaches such as polymer coatings with antibacterial compounds and use of non-toxic silicone-based foul-release coatings (FRC) are being researched (Chambers et al, 2006, Sawant et al, 2013. The latter does not prevent biofouling, but allows it to be easily dislodged, as it possesses properties such as low surface energy, hydrophobicity and low elastic modulus (Brady and Singer, 2000;Brady, 2001).…”

A Relook at Food Packaging for Cost Effective by Incorporation of Novel Technologies

“…Nanoparticles have an extremely large relative surface area to volume, and hence increasing their contact with bacteria or fungi, vastly improve their bactericidal and fungicidal effectiveness. They bind to microbial DNA, preventing bacterial replication, and to sulfhydryl groups in the metabolic enzymes of the bacterial electron transport chain, causing their inactivation [82]. Pertaining to current literature available information here we tried to relook for the natural sources, and technology.…”