Mesenchymal Stem Cells Encapsulated and Aligned in Self-Assembling Peptide Hydrogels

Abstract

This study presents a viable strategy using fmoc-protected peptides hydrogels, to encapsulate and stretch mesenchymal stem cells (MSC). To explore the peptide hydrogel potential, a custom mechanical stretching device with polydimethylsiloxane (PDMS) chambers were used to stretch MSCs encapsulated in Fmoc hydrogels. We investigated the impact of fmoc- FF prepared in dimethyl sulfoxide (DMSO), 1,1,1,3,3,3-hexafluoro-2-propanol (HFP) and deionizied water in the self-assembly, and mechanical properties of the gels. The peptide hydrogel is formed through molecular self-assembly of peptide sequence into β-sheets that are connected with the π-π aromatic stacking of F-F groups. The hydrogels provided a stiff, hydrated gel with round nanofiber morphology representing an elastic modulus of 174-266 KPa. MSCs cultured on peptide hydrogels undergo viability, morphology, and alignment evaluations using MTT, live/dead, and phalloidin (F-actin) staining. The F-actins of 3D- cultured MSCs in Fmoc-FF/HFP, and Fmoc-FF/DMSO followed by mechanical stretching showed elongated morphology with defined microfilament fibers compared to the round and spherical F-actin shape of the control cells. Peptide gels with 5mM concentration preserved 100% viability of MSC. Results reveals the feasibility and conditions for successful cell encapsulation and alignment within peptide hydrogels. Encapsulation of MSC in peptide nanofiber followed by a stretching process present a promising tissue engineering platform. By enhancing our understanding of MSC-peptide hydrogel interactions, this research con- tributes to the development of biomaterials tailored for regenerative medicine.