Functionally graded hydrogels with opposing biochemical cues for osteochondral tissue engineering

Aman Mahajan; Zahra Sifat Zaidi; Amit Shukla; Rakshita Saxena; Dhirendra S Katti

doi:10.1088/1758-5090/ad467e

Functionally graded hydrogels with opposing biochemical cues for osteochondral tissue engineering

Biofabrication. 2024 May 2. doi: 10.1088/1758-5090/ad467e. Online ahead of print.

Authors

Aman Mahajan¹, Zahra Sifat Zaidi², Amit Shukla², Rakshita Saxena³, Dhirendra S Katti⁴

Affiliations

¹ Department of Biological Science and Bioengineering, Indian Institute of Technology Kanpur, Lab 16, Department of BSBE, IIT Kanpur, Kanpur Nagar, Kanpur, Uttar Pradesh, 208016, INDIA.
² Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Lab 16, Department of BSBE, IIT Kanpur, Kanpur, Uttar Pradesh, 208016, INDIA.
³ Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Department of BSBE, IIT Kanpur, Kanpur, Uttar Pradesh, 208016, INDIA.
⁴ Department of Biological Science and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (U.P), Kanpur, 208016, INDIA.

PMID: 38697073
DOI: 10.1088/1758-5090/ad467e

Abstract

Osteochondral tissue (OC) repair remains a significant challenge in the field of musculoskeletal tissue engineering. OC tissue displays a gradient structure characterised by variations in both cell types and extracellular matrix components from cartilage to the subchondral bone. These functional gradients in the native tissue have been replicated to engineer osteochondral tissue in vitro. While diverse fabrication methods have been employed to create these microenvironments, emulating the natural gradients and effective regeneration of the tissue continues to present a significant challenge. In this study, we present the design and development of an interpenetrating (IPN) hydrogel with opposing dual biochemical gradients with the aim of regenerating the complete osteochondral unit. The gradients of biochemical cues were generated using an in-house built extrusion system in CMC-Silk IPN hydrogel having improved mechanical strength. Firstly, we fabricated a hydrogel that exhibits a smooth transition of sCMC and TGF-β1 (SCT gradient hydrogel) from the upper to the lower region of the IPN hydrogel, with the intent of regenerating the cartilage layer. Secondly, a hydrogel with a HAp gradient (HAp gradient hydrogel) from the lower to the upper region was fabricated to facilitate the regeneration of the subchondral bone layer. Subsequently, we developed a dual biochemical gradient hydrogel with the goal of regenerating the entire osteochondral unit. The fabricated hydrogel demonstrated a smooth transition of sCMC + TGF-β1 and HAp gradients in opposing directions, along with a blend of both the biochemical cues at the interface. The results showed that the hydrogels having biochemical cues corresponding to the three zones (i.e., cartilage, interface and bone) of dual biochemical gradient hydrogel led to differentiation of BMSCs towards their respective lineages, thereby demonstrating their efficacy in directing the fate of progenitor cells. The developed dual gradient hydrogel provided biochemical signals that have the potential to facilitate tissue growth and regeneration of the entire osteochondral tissue with a smooth transition from cartilage (soft) to bone (hard) tissues. In summary, our study provides a simple and innovative method for incorporating biochemical cues into hydrogels. This promising approach is translatable and has the potential to be extrapolated to other interface tissues.&#xD.

Keywords: Dual biochemical cues; Gradient hydrogel; Hydroxyapatite; Osteochondral tissue engineering; Photo-crosslinking; Sulfated carboxymethyl cellulose; Transforming growth factor-β.