Biodegradability of poly(lactic-co-glycolic acid) irradiated with femtosecond laser pulses without material removal

The degradation rates of biodegradable polymers are necessary to be controlled for tissue scaffold applications. In this work, we demonstrate that the degradation rate of poly(lactic-co-glycolic acid) (PLGA) was accelerated by irradiating with femtosecond laser pulses under the condition where material removal, i.e., laser ablation had not occurred. Scanning electron microscopy observation showed that the degradation rate was accelerated without significant laser ablation. The analysis of Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy revealed that the chemical properties of the PLGA had changed by femtosecond laser pulses irradiation. Furthermore, we have investigated the degradation of PLGA when the femtosecond laser pulses were focused inside the material. After the degradation, the PLGA showed enhanced optical scattering region in the depth of 300 µm from the surface. The results indicate that high-aspect-ratio modification and degradation are possible by changing the depth of focus of femtosecond laser pulses under the conditions where the direct removal of the material was not occurred.