Femtosecond-laser-assisted LIPSS generation on chitosan/hydroxyapatite thin layers for biomedical applications

Abstract

In this work, chitosan/hydroxyapatite (Ch/HAp) thin composites were synthesized and examined before and after femtosecond laser irradiation in order to investigate the substrate response and surface changes occurring during the process. The zones of interaction formed after treatment by fs laser pulses were analysed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results revealed that the laser processing of Ch/HAp thin films leads to generation of well-defined laser-induced periodic surface structures (LIPSS) for a laser fluence F = 2.07 J/cm² at 800 nm wavelength with pulse durations in the range of 130 fs. It is demonstrated experimentally that the femtosecond interaction regime results in the formation of ripples beneficial for the functionalization of biopolymer/ceramic samples for further tissue engineering applications. In the transmittance spectra, profile variations for the non-treated and laser-processed surfaces were noticed depending on the number of pulses applied.