Investigation of the Young’s Modulus of Fibers in an Electrospun PCL Scaffold Using AFM and its Correlation to cell Attachment

Abstract

Seeding a layer of cells at specific depths within scaffolds is an important optimization parameter for bi-layer skin models. Experimental investigation has been performed to investigate the effect of fiber diameter and its mechanical property on the depth of cell seeding of for electrospun fiber scaffold. Polycaprolactone (PCL) is used to generate scaffolds that are submicron (400nm) to micron (1100nm) using electro-spinning. 3T3 fibroblasts were seeded on the electro-spun fiber scaffold mat of 50-70 microns thickness in this study. In order to investigate the effect of fiber diameter on cell migration, first, the electrospun fiber scaffold was studied for variation of mechanical properties as a function of fiber diameters. Atomic force microscopy (AFM) was used to investigate the Young’s modulus (E) values as a function of fiber diameter. It was identified that as the fiber diameter increases, the Young’s modulus values decreases considerably from 1.9GPa to 600MPa. The variation in E is correlated with cell seeding depth as a function of vacuum pressure. A higher E value led to a lower depth of cell seeding (closer to the surface) indicating that nano-fibrous scaffolds offer larger resistance to cell movement compared to microfibrous scaffolds