Microfluidic Encapsulation of Human Mesenchymal Stem Cells for Articular Cartilage Tissue Regeneration

Abstract

Stem cell injections for the treatment of articular cartilage damage are a promising approach to achieve tissue regeneration. However, this method is encumbered by high cell apoptosis rates, low retention in the cartilage lesion, and inefficient chondrogenesis. Here, we have used a facile, very low cost-based microfluidic technique to create visible light-cured microgels composed of gelatin norbornene (GelNB) and a poly(ethylene glycol) (PEG) cross-linker. In addition, we have demonstrated that the process enables the rapid in situ microencapsulation of human bone marrow-derived mesenchymal stem cells (hBMSCs) under biocompatible microfluidic-processing conditions for long-term maintenance. The hBMSCs exhibited an unusually high degree of chondrogenesis in the GelNB microgels with chondro-inductive media, specifically toward the hyaline cartilage structure, with significant upregulation in type II collagen expression compared to the bulk hydrogel and "gold standard" pellet culture. Overall, we have demonstrated that these protein-based microgels can be engineered as promising therapeutic candidates for articular cartilage regeneration, with additional potential to be used in a variety of other applications in regenerative medicine.

Biopolymer Microparticles Prepared by Microfluidics for Biomedical Applications

“…Then, L929 fibroblasts were successfully grown on the resultant cell‐loaded Gelatin‐Ph microcapsules, indicating the feasibility for achieving artificial tissue constructs. Meanwhile, gelatin norbornene (GelNB) was utilized to fabricate gelatin microspheres via visible light‐induced bio‐orthogonal thiol‐norbornene photoclick reaction . MSCs were successfully loaded in the GelNB microspheres without potentially harmful UV light during crosslinking for long‐term maintenance.…”

“…reaction. [144] MSCs were successfully loaded in the GelNB microspheres without potentially harmful UV light during crosslinking for long-term maintenance. The MSC-laden microspheres exhibited a high degree of chondrogenesis upon the incubation in chondrogenic induction media, with significant upregulation in type II collagen expression.…”

Obstacles and challenges for tissue engineering and regenerative medicine: Australian nuances

“…There were many reports of such plasticity, with multi‐ or pluripotent stem cells being isolated from interstitial and circulating cells and other sources, as reviewed for differences in regenerative capacity of skeletal and cardiac muscles with limited capacity for stem cell renewal of mammalian cardiac muscle continuing to be emphasised . MSCs remain of much interest for generation of cells for transplantation, as demonstrated for human bone marrow‐derived MSCs (hBMSCs) used for cartilage repair, where microencapsulation enhanced their survival and efficacy . Unfortunately, some speculation about the potential of stem cell therapies, including MSCs, for clinical applications has been inflated, unrealistic and misleading raising serious ethical and regulatory issues related to inappropriate marketing of unproven stem cell treatments …”

“…19 MSCs remain of much interest for generation of cells for transplantation, as demonstrated for human bone marrow-derived MSCs (hBMSCs) used for cartilage repair, where microencapsulation enhanced their survival and efficacy. 20 Unfortunately, some speculation about the potential of stem cell therapies, including MSCs, for clinical applications has been inflated, unrealistic and misleading raising serious ethical and regulatory issues related to inappropriate marketing of unproven stem cell treatments. [21][22][23] A major breakthrough occurred about 20 years ago when human embryonic stem cells (hESCs), isolated from the inner cell mass of a blastocyst (produced through in vitro fertilization, with spare embryos donated for research purposes), were able to be directed into many lineages in tissue culture and were confirmed to be pluripotent with the unique ability to differentiate into cells of all tissues in the body.…”

Bioorthogonal hydrogels by thiol–halide click crosslinking with fast gelation time and tunable stability in aqueous media

“…5 wt % in fully swollen stage) and is expected to have minimal toxicity on the encapsulated cells. A seeding density of 2.5 × 10 6 cell mL −1 was used, in accordance with our previous work on 3D cell encapsulation 20,30,31 and work reported by other groups. 32,33 Live/dead staining of the cell-laden hydrogels showed both cell types are viable with about 85% of live cells (Fig.…”