Chemically Defined Medium With TGF-β₃ Enhances Matrix Elaboration by Nucleus Pulposus Cells Encapsulated in Novel Photocrosslinked Carboxymethylcellulose Hydrogels

Back pain is a significant clinical concern often attributed to degeneration of the intervertebral disc (IVD) and the associated dehydration of the nucleus pulposus (NP) [1]. The NP is a gel-like tissue at the center of the disc, rich in proteoglycans and type II collagen that functions to resist compressive forces through the generation of a hydrostatic swelling pressure [2]. Tissue engineering strategies may provide a viable NP replacement therapy as an alternative to current surgical procedures. However, several factors including medium formulation and scaffold selection can affect construct maturation [3]. For example, transforming growth factor-beta 3 (TGF-β₃) has been shown to enhance the functional properties of tissue engineered cartilage constructs, with more pronounced results observed in serum-free conditions [3]. NP cells are commonly cultured in ionically crosslinked alginate hydrogels to maintain their phenotypic properties; however, these scaffolds have been shown to lose structural integrity over time, creating a need for an alternative biomaterial [4]. Therefore, the objective of this study was to examine the effects of medium formulation on NP cells encapsulated in novel photocrosslinked carboxymethylcellulose (CMC) hydrogels.