Surface chemistry of nanobiomaterials with antimicrobial activity

Abstract

Biofilms are common in nature and are often associated with undesirable effects such as the deterioration of concrete, metal corrosion, fouling of oil and gas pipelines and ships hulls, dental plaques causing tooth decay, and microbial colonization of indwelling or percutaneous medical devices, such as catheters, artificial valves, joints, and stents. Nanomaterials with distinctive physicochemical properties and high surface areas are offering new alternatives for the development of antibiofilm and bactericidal surfaces. In order to obtain antimicrobial coatings several approaches will be described. One approach consists of using a controlled-release nanostructured coating, in which the antibiotic is released from the biomedical device and intercepts bacteria in the vicinity. The disadvantage of the release approach is that the duration and effectiveness of antibacterial action are limited by loading and release kinetics. The second approach consists on the application of a molecular surface layer of covalently immobilized (“grafted”) molecules or on the modification of surface nanotopography, which can prevent bacterial attachment to material surfaces by either killing bacteria or changing physicochemical characteristics of the surfaces (hydrophobicity/hydrophilicity, charge, surface free energy, nanoroughness). In addition, much longer, perhaps indefinite, effectiveness can be ascertained by using this approach.