Photochemical surface modification of polymers for biomedical applications

Abstract

We describe here the modification of various polymers (polytetrafluoroethylene, polyethyleneterephthalate, and polyvinyl alcohol) by UV-irradiation with wavelengths below 200 nm in an inert or reactive atmosphere. The light sources employed are F 2 -or excimer lasers and excimer lamps. The reactive gases include ammonia (NH 3 ), acetylene (C 2 H 2 ), and oxygen (O 2 ). Photo-dissociated fragments of these gases can react with the polymers or be deposited thereon, resulting in new chemical groups at the surface. Special emphasis is put to improved adhesion of biological cells at these modified surfaces. Potentials applications include cell coated medical implants and prostheses as well as cell micro-arrays for high throughput screening.

Post-Polymerization Modification of Fluoropolymers via UV Irradiation in the Presence of a Photoacid Generator

“…Physicochemical methods are related to alterations in the chemical composition of the surfaces employing techniques such as active-gas or vapor treatment for deposition of a thin film onto the surface [ 10 , 13 ] or alteration of surface texture [ 14 , 15 , 16 ], exposure to radiation (ultraviolet [ 13 , 17 , 18 , 19 , 20 ] or extreme ultraviolet [ 7 ]), treatment of the surface with solvents [ 21 , 22 , 23 ], bulk phase desorption or combination of those treatments [ 10 , 13 , 18 , 24 ]. Mechanical methods are related to the alternation of the surface texture through mechanical roughening/polishing (e.g., sandblasting) [ 25 ] and micromanipulation (e.g., using AFM, STM probes).…”

“…They observed that the F atoms of the polymer were substituted from H atoms, produced from the dissociation of the exposed ammonia molecules, rendering the surface more hydrophilic compared to the untreated one. This modification enhanced cell adhesion and proliferation onto the treated versus the untreated surfaces [ 13 , 18 ].…”