Cryogenically Structured Extracellular Matrix Mimetic Based on a Concentrated Collagen-Containing Solution

A new macroporous cryogenically structured biomimetic of the extracellular matrix (ECM) was prepared on the basis of a commercially available concentrated collagen-containing solution, and the possibility of its use in tissue engineering was assessed. Spongy collagen-containing material was fabricated by sequential freezing of a concentrated collagen-containing solution, its subsequent lyophilization, followed by chemical tanning by treatment with an alcohol solution of carbodiimide. The morphology of the cryostructured multicomponent collagen-containing material was studied by optical and scanning electron microscopy (SEM) using lanthanide contrast. The cytotoxicity of the matrix was studied in a culture of human adipose tissue-derived mesenchymal stromal cells (hADSCs). Adhesion and proliferation of hADSCs on the surface of the matrix were studied on the seventh day of cultivation. The compression modulus of elasticity of the resulting collagen-containing material in a water-swollen state was 35.3 ± 2.2 kPa, the total water-holding capacity of the material was 45.80 ± 0.46 mL/g of polymer, and the degree of swelling of the macropore walls was 3.99 ± 0.31 mL/g. During SEM examination and histological staining with hematoxylin and eosin, a large-pored structure was observed on the surface and cross section of the disk. The pores in the upper part are larger (average diameter at least ~30 µm) than the pores in the lower part of the sponge (average diameter at most ~30 µm) owing to the occurrence of a vertical temperature gradient. The matrix did not have cytotoxicity toward hADSCs. In the sample, active proliferation of hADSCs was observed on the surface of the matrix. The lack of cytotoxicity and the ability to support the adhesion and proliferation of hADSCs indicate the possibility of using cryogenically structured extracellular matrix biomimetic in tissue engineering and regenerative medicine.