Poly (ethylene glycol) hydrogel scaffolds with multiscale porosity for culture of human adipose-derived stem cells

Three-dimensional (3 D) hydrogel scaffolds are an attractive option for tissue regeneration applications because they allow for cell migration, fluid exchange, and can be synthesized to closely mimic the physical properties of the extracellular matrix environment. The material properties of hydrogels play a vital role in cellular migration and differentiation. In light of this, in-depth understanding of material properties is required before such scaffolds can be used to study their influence on cells. Herein, various blends and thicknesses of poly (ethylene glycol) dimethacrylate (PEGDMA) hydrogels were synthesized, flash frozen, and dried by lyophilization to create scaffolds with multiscale porosity. Environmental scanning electron microscopy (ESEM) images demonstrated that lyophilization induced microporous voids in the PEGDMA hydrogels while swelling studies show the hydrogels retain their innate swelling properties. Change in pore size was observed between drying methods, polymer blend, and thickness when imaged in the hydrated state. Human adipose-derived stem cells (hASCs) were seeded on lyophilized and non-lyophilized hydrogels to determine if the scaffolds would support cell attachment and proliferation of a clinically relevant cell type. Cell attachment and morphology of the hASCs were evaluated using fluorescence imaging. Qualitative observations in cell attachment and morphology of hASCs on the surface of the different hydrogel spatial configurations indicate these multiscale porosity hydrogels create a suitable scaffold for hASC culture. These findings offer another factor of tunability in creating biomimetic hydrogels for various tissue engineering applications including tissue repair, regeneration, wound healing, and controlled release of growth factors.