User-defined and localized cellular alignment using femtosecond laser hydrogel densification

摘要

Organized cellular alignment is critical for variety of biological phenomenon as well as necessary for several tissueengineering applications. Although a variety of methods have been used to control cellular alignment in 2D, recapitulatingthe organized 3D cellular alignment found within native tissues remains a challenge. In this study, we present a new methodto align cells in localized user-defined orientations using femtosecond (fs) laser enabled hydrogel densification. Fs laserdirect writing was used to induce densification within partially crosslinked gelatin methacrylate (GelMA) hydrogel.Densified line patterns were used to preferential align variety of cells such as mouse 10T1/2s fibroblasts and IDG-SW3osteocytes, and human HUVECs and hiPSC-derived MSCs. Cellular alignment as a function of cell-culture time, linespacing, and modification-depth were characterized. As compared to the current technology, this method can be appliedto any photocrosslinkable hydrogel, as it does not require specialized chemical or physical modifications or any externalguidance cues. Additionally, densification can be introduced during active cell culture providing temporal flexibility inexperimental design. This method can be potentially used for the creation of organized engineered tissues.