Peptide-Self-Assembly-Based Construction Of 3D Scaffolds For Cell Culture And Its Property Study

Biopolymer hydrogels have been widely used in food and pharmaceutical industries as well as in tissue engineering, drug delivery and microfluidics. In soft material research, these peptide hydrogels formed by peptide self-assembly have been explored extensively in recent years owing to their good biocompatibility, low biodegradability and ease to synthesis of various biologically functional hydrogels. They have a wide range of applications, e.g. scaffolds for wound healing, sustained release of drugs and biomolecules, cell culture media and tissue engineering, template for nanofabrication, catalysts for organic reactions, and for pollutant removal from waste water etc.Based on peptide NapGFFYE-SS-EERGD using a disulfide bond as a cleavable linker, ultrashort aromatic peptide containing photodegradable functional groups NapGFFY-PDF-E(P1) was synthesized utilizing Fmoc solid-phase synthesis method. Addition of glutamic acid and lysine, a mutant sequence NapGFFYK-PDF-EE (P2) was obtained. The peptide sequences containing photodegradable functional groups (PDF) could be fractured by UV irradiation to two parts. One of them with naphthalene ring groups could self-assemble into moderately rigid nanofiber hydrogel. We mainly investigated the differences in the self-assembly behaviors of these two peptides from three aspects including gelation property, micromorphology and gel strength.We found that the hydrogels have great potentials to be used as three-dimensional cell culture scaffolds in the three-dimensional cell culture experiments.We found that the gelation time of the photosensitive hydrogels was proportional to the peptide concentrations and light intensity. Under the same concentration, the gelation time of P2 was shorter than P1. Besides, we also observed that the micromorphology of the photo-responsive hydrogels was composed of randomly distributed long intertwined fibrous network and the density of nanofibers was positively correlated to the peptide concentrations. Under the same concentration, nanofibers in the hydrogel P2 were more intensive than P1. Moreover, we found that the storage modulus of the hydrogels P2 was greater than P1, up to about 1000 Pa, which was capable of holding the cell in three-dimensional scaffolds. The hydrogels also showed good self-healing capability, suggesting they have great potentials to be used as novel injectable cell therapy carriers. We observed that the viability of cells in gel P2 was more than ninety percent, and cells could be uniformly distributed in the hydrogel. It might have great potentials to be used as a photo-switchable biocompatible three-dimensional cell culture scaffolds.We designed two photo-sensitive hydrogels P1 and P2 via optimization of peptide sequences and studied their physical properties. We found that hydrogels P2 had good physical properties and short gelation time, which could raise the viability of cells in a gel. Therefore, the photo-responsive hydrogels could be used as three-dimensional cell culture scaffolds, and might have great application potentials in the field of tissue engineering.