Non-animal derived recombinant collagen-based biomaterials as a promising strategy towards adipose tissue engineering

Adipose tissue engineering (ATE) has been gaining increasing interest over the past decades, offering promise for new and innovative breast reconstructive strategies. Animal-derived gelatin- methacryloyl has already been applied in a plethora of TE strategies. However, due to clinical concerns, related to the potential occurrence of immunoglobulin (IgE)-mediated immune responses and pathogen transmission, a shift towards defined, reproducible recombinant proteins has occurred. In the present study, a recombinant protein based on human collagen type I, enriched with arginine-glycine-aspartic acid (RGD) was functionalized with photo-crosslinkable methacryloyl moieties (RCPhC1-MA), processed into 3D scaffolds and compared with frequently applied gelatin-methacryloyl (Gel-MA) from animal origin using an indirect printing method applying poly-lactic acid (PLA) as sacrificial mould. For both materials, similar gel fractions (> 65 %) and biodegradation times were obtained. In addition, a significantly lower mass swelling ratio (17.6 ± 1.5 versus 24.3 ± 1.4) and mechanical strength (Young's modulus: 1.1 ± 0.2 kPa versus 1.9 ± 0.3 kPa) were observed for RCPhC1-MA compared to Gel-MA scaffolds. In vitro seeding assays showed similar cell viabilities (> 80 %) and a higher initial cell attachment for the RCPhC1-MA scaffolds. Moreover, the seeded adipose-derived stem cells could be differentiated into the adipogenic lineage for both Gel-MA and RCPhC1-MA scaffolds, showing a trend towards superior differentiation for the RCPhC1-MA scaffolds based on the triglyceride and Bodipy assay. RCPhC1-MA scaffolds could result in a transition towards the exploitation of non-animal-derived biomaterials for ATE, omitting any regulatory concerns related to the use of animal derived products.