Development of antimicrobial and antithrombogenic coatings for inside and outside of medical catheters

Abstract

Catheter-related infections are costly problems for hospitals around the world. Protection of the body against infection involves not only the immune system, but also the integrity of the external skin and internal mucosal surface. Catheters, introduced from the outside into the interior of the body, breach this important defense and lay the patient open to the risk of infection. It is believed that the surface characteristics of the polymers used in today's catheters are, to a large degree, responsible for this. In particular, the surface roughness, the hydrophobic nature of the surface and the ability of certain types of common bacteria to attach to and metabolize on the polymers are at fault. Interestingly, prior to the 1950s, when venous access required the use of rigid stainless steel needles, catheter infection was a minor problem. This has led us to develop various metal coatings (e.g. Ag, Pt, etc.) both for inside and outside of even the smallest catheter of 1 mm in diameter. Electroless deposition has been used for silver coating of both inside and outside of catheters, while hollow cathode magnetron and vacuum arc deposition have been used for outside coating. High-quality adherent metallic films have been deposited on Teflon, polyimide and latex substrates. Both biological and animal tests have shown the excellent antimicrobial and good mechanical durability of these films. The fabrication processes, results of thin film characterizations and investigations of antimicrobial effects are discussed. The biocompatibility of the chosen metals is also addressed. © 1994.