Extracellular-Matrix-Based and Arg-Gly-Asp–Modified Photopolymerizing Hydrogels for Cartilage Tissue Engineering

Abstract

Articular cartilage damage is a persistent and increasing problem with the aging population. Strategies to achieve complete repair or functional restoration remain a challenge. Photopolymerizing-based hydrogels have long received an attention in the cartilage tissue engineering, due to their unique bioactivities, flexible method of synthesis, range of constituents, and desirable physical characteristics. In the present study, we have introduced unique bioactivity within the photopolymerizing-based hydrogels by copolymerizing polyethylene glycol (PEG) macromers with methacrylated extracellular matrix (ECM) molecules (hyaluronic acid and chondroitin sulfate [CS]) and integrin binding peptides (RGD peptide). Results indicate that cellular morphology, as observed by the actin cytoskeleton structures, was strongly dependent on the type of ECM component as well as the presence of integrin binding moieties. Further, CS-based hydrogel with integrin binding RGD moieties increased the lubricin (or known as superficial zone protein [SZP]) gene expression of the encapsulated chondrocytes. Additionally, CS-based hydrogel displayed cell-responsive degradation and resulted in increased DNA, GAG, and collagen accumulation compared with other hydrogels. This study demonstrates that integrin-mediated interactions within CS microenvironment provide an optimal hydrogel scaffold for cartilage tissue engineering application.

Graphene oxide reinforced hydrogels for osteogenic differentiation of human adipose-derived stem cells

“…Our previous study reported micro-sized protrusions when cells were encapsulated in PEG-based hydrogels containing RGD peptide. 11,12,35 Interestingly, similar to the RGD-functionalized hydrogel, distinct cellular protrusions were evident in PEGDA-GO hydrogel. Based on the assumption that the extension of actin bers was induced by the adhesive interaction of cells with GO, we observed direct morphological responses of the seeded cells to the hydrogel surfaces ( Fig.…”

Inflammation-Modulating Hydrogels for Osteoarthritis Cartilage Tissue Engineering

“…Methacrylate or acrylate-conjugated polymers are commonly used for in situ photocrosslinkings. Kim et al, incorporated photoreactive methacrylates to a CS or HA backbone and mixed either ECM component with PEG [41]. Since PEG lacks cell-binding moiety and is biologically inert, a tripeptide composed of arginine, glycine, and aspartate (RGD) was conjugated to PEG to promote cell adhesion.…”

Microsphere-Based Scaffolds Carrying Opposing Gradients of Chondroitin Sulfate and Tricalcium Phosphate

“…Chondroitin sulfate (CS), a glycosaminoglycan (GAG) and a key ECM component of cartilage, when incorporated into 3D scaffolds resulted in increased DNA, GAG, and collagen accumulation by the cultured cells (Uygun et al, 2009 ; Kim et al, 2014 ). Moreover, CS also enhanced their chondrogenic gene expression (Chen et al, 2013 ).…”