Investigation into the efficacy of CO₂ lasers for modifying the factors influencing biocompatibility of a polymeric biomaterial in comparison with an F₂ excimer laser

Enhancement of the biocompatibility of a material by means of laser radiation has been amply demonstrated previously. Due to efficient absorption of the energy, short wavelengths and energies per pulse, polymers are usually processed using UV lasers, but the processing of polymers with IR lasers has also been demonstrated previously. In this work a comparative study for the surface modification of nylon 6,6 has been conducted in order to vary the parameters driving biocompatibility (surface topography, hydrophobic reactions, hydrophilic reactions and surface chemistry) using CO₂ and excimer lasers. Topographical changes were analysed using white light interferometry which indicated that both laser systems could be implemented for modifying the topography of nylon 6,6. Variations in the surface chemistry were evaluated using EDX and XPS analysis and showed that the O₂ increased and decreased for the CO₂ and F₂ laser irradiated samples, respectively. Modification of the hydrophobic and hydrophilic reactions was quantified by measuring the contact angle, which was found to increase in all instances for both laser systems. It is proposed that the increase in contact angle, especially for the CO₂ laser irradiated samples, is due to a change in wetting regime as a result of the surface pattern produced.