Micropatterning and characterization of electrospun PCL/gelatin nanofiber tissue scaffolds by femtosecond laser ablation

PCL/gelatin is a biodegradable polymer blend with good biocompatibility, mechanical, physical and chemical properties that is a promising material for use in fabrication of electrospun (ES) nanofiber tissue engineering scaffolds. Although ES nanofiber scaffolds provide a favorable extracellular matrix, microscale surface patterns are needed for study and control of cell adhesion, proliferation and migration. However, micro-patterning of ES polymer/biomaterial blended nanofibers with available techniques is difficult due to its fibrous surface texture and biomaterial content. In this work, the effects of direct-write femtosecond laser ablation on electrospun PCL/gelatin nanofiber tissue scaffold surface morphology and chemistry and resulting growth rate of deposited cells was investigated. Scanning electron microscope (SEM) images showed that laser ablation did not change the statistical distributions of fiber diameter and surface porosity. Attenuated Total Reflectance Fourier Transform Infrared (ATR- FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) revealed no changes in the chemical states of PCL/gelatin nanofiber before and after femtosecond laser irradiation. In vitro, mouse embryonic stem (mES) cell initial growth rates were similar on both as-spun surface and micropockets made by femtosecond laser ablation. It was concluded that femtosecond laser processing is effective for creating 3-dimensional microscale patterns on ES nanofiber tissue scaffolds.