Biodegradable, Photocrosslinked Alginate Hydrogels with Independently Tailorable Physical Properties and Cell Adhesivity

Abstract

Biocompatible polymers capable of photopolymerization are of immense interest for tissue engineering applications as they can be injected in a minimally invasive manner into a defect site and, then upon application of ultraviolet light, rapidly form hydrogels in situ. Cell adhesion interactions with a biomaterial are known to be important in regulating cell behaviors such as proliferation and differentiation. Therefore, we have covalently modified photocrosslinkable alginate with cell adhesion ligands containing the Arg-Gly-Asp amino acid sequence to form biodegradable, photocrosslinked alginate hydrogels with controlled cell adhesivity. This unique polymer system allows for independent modulation of the physical and biochemical signaling environment presented to cells. The physical properties of the hydrogels such as elastic moduli, swelling ratios, and degradation profiles were similar at the same crosslinking density regardless of the presence of adhesion ligands. Chondrocytes seeded on the surface of the adhesion ligand-modified hydrogels were able to attach and spread, whereas those seeded on unmodified hydrogels exhibited minimal adherence. Importantly, the adhesion-ligand-modified hydrogels enhanced the proliferation and chondrogenic differentiated function of encapsulated chondrocytes as demonstrated by increased DNA content and production of glycosaminoglycans compared to unmodified control hydrogels. This new photocrosslinkable, biodegradable biomaterial system in which the soluble (e.g., growth factors) and insoluble (e.g., cell adhesion ligands) biochemical signaling environment and the biomaterial physical properties (e.g., the elastic moduli) can be independently controlled may be a powerful tool for elucidating the individual and combined effects of these parameters on cell function for cartilage tissue engineering and other regenerative medicine applications.

Stiffness of photocrosslinked RGD‐alginate gels regulates adipose progenitor cell behavior

“…Consequently, photocrosslinked alginate gels without adhesion peptides do not permit studies of APC behavior as a function of 3D matrix rigidity. To address this challenge, we have developed a protocol that involves RGD modification of methacrylated alginate, similar to a recently published method (Jeon et al, 2010). Additionally, we have systematically tested different photoinitiators for the crosslinking of these materials.…”

3D Bioprinting of Developmentally Inspired Templates for Whole Bone Organ Engineering

“…274 mg sulfo-NHS (Pierce, Rockford, IL), 484 mg EDC (Sigma), and 100 mg GGGGRGDSP peptide (AIBioTech, Richmond, VA) were then added into alginate solution. The reaction was stopped and the solution was purified and lyophilized as previously described [39] . GelMA was synthesized by reaction of porcine type A gelatin (Sigma Aldrich) with methacrylic anhydride (Sigma Aldrich) at 50 °C for four hours, as previously described [40] .…”

A Silk Fibroin and Peptide Amphiphile‐Based Co‐Culture Model for Osteochondral Tissue Engineering

“…Moreover, photocrosslinkable alginate hydrogels were fabricated with RGD modifi cation and this biomaterial enhanced chondrogenic potential of chondrocytes compared to unmodifi ed one. [ 54 ] In our study, hACs were directly interacted with bioactive epitope, RGDS in this case, to exhibit better cell adhesion. That is why higher cell proliferation was obtained in PA-RGDS hydrogels compared to pellet culture as shown by Alamar blue analysis.…”