Improving fluid retention properties of 316L stainless steel using nanosecond pulsed laser surface texturing

Abstract

Stainless steel has been used as a successful biomaterial for decades. In this study, a pulsed nanosecond laser was used to create patterned surfaces of stainless steel coupons to study the effect of patterning on fluid retention and biocompatibility studies of laser patterned and control surfaces. An AVIA 355 nanosecond pulsed laser was used with different laser parameters to create unique “peak and valley” structures (uniform textured surface) on stainless steel coupons of size of 1 × 1 × 0.1 cm3. The surface structural changes can be attributed to the Gaussian beam profile of the laser. The coupons were observed under a scanning electron microscope to understand the change of the material surface profile. An optical profilometer was used to measure the surface roughness and compare it with a nontextured or control surface. The contact angle measurement showed a decrease in the contact angle, reduced to 71.6° from 82.2° making the patterned surface more hydrophilic. A biocompatibility study of the stainless steel was performed to evaluate the effect of surface modification on its impact on biocompatibility. The cell viability of the patterned sample was 94% as compared to 84% for the unpatterned surface. A simulation of the process was run using flow3d® to understand the behavior of the material during the texturing process. The results obtained from the simulation process were compared with the experimental data and found to be in good agreement. The effects of Gaussian beam, vapor pressure, and overlapping of the beam were also analyzed in the simulation process.