Tailoring surface properties, biocompatibility and corrosion behavior of stainless steel by laser induced periodic surface treatment towards developing biomimetic stents

Laser-Induced Periodic Surface Structures (LIPSS) holds great potential for regenerative biomedicine. Creating highly precise LIPSS enables to generate biomimetic implant surfaces with improved properties. The present study focuses on the fabrication and investigation of laser-treated stainless steel samples with applied linear LIPSS patterns with grooves made by means of a picosecond laser system using wavelengths of 1064 nm and 532 nm. To investigate properties of the laser-treated surfaces and to understand the basics of cell-surface interactions between the LIPSS and human Umbilical Cord Mesenchymal Stem Cells (UCMSC), flat stainless steel samples with various applied nanopatterns were used. Such LIPSSs demonstrated higher surface roughness, good biocompatibility, lower wettability and higher corrosion resistance compared to the untreated (polished) spec-imens. The surface roughness of laser-treated samples was in microscale that enabled adhesion and migration of endothelial cells, thus increasing the likelihood for endothelialisation. This thereby could reduce the chances for the development of Late Stent Thrombosis (LST) and In-Stent Restenosis (ISR). Furthermore, laser textured surfaces demonstrated an environment supportive for cell attachment, proliferation and alignment with the nanogroves. Therefore, application of the biomimetic nanopatterns could help to overcome frequent post-surgery complications after the stent implantation

Enhanced properties of poly(ε-caprolactone)/polyvinylpyrrolidone electrospun scaffolds fabricated using 1,1,1,3,3,3-hexafluoro-2-propanol

Poly(ε-caprolactone)/polyvinylpyrrolidone (PCL/PVP) scaffolds with various composition were fabricated from 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) solution using the same electrospinning parameters in order to reveal the effect of polymer ratio on the material properties. The obtained materials were characterized using scanning electron microscopy, contact angle measurements, X-ray diffraction, Fourier-transformed infrared spectroscopy, and tensile testing. The strengthening effect of PVP was observed: Young modulus of PCL/PVP scaffold with 50/50 polymer ratio was found at 105.4 ± 8.4 MPa which is six times higher comparing to those of PCL scaffold. PVP-containing scaffolds were extremely hydrophilic with PVP concentration of 5 wt% (vs. 25 wt% in previous reports) leading to full wetting of the material. in vitro studies showed an improved viability of HeLa cells cultured with the composites containing higher concentrations of PVP. Owing to the application of HFIP, PCL-based materials were loaded with cyclophosphamide for the first time and the PVP-containing materials demonstrated the intensified initial release of the model compound. Utilizing HFIP for the fabrication of PCL/PVP scaffolds significantly widens their application for drug delivery systems due to a good solubility of proteins, drugs, and other biologically active compounds in this solvent