In Vitro Fabrication and Physicochemical Properties of a Hybrid Fibril from Xenogeneic Collagens

A Hybrid collagen fibril (HCF) assembled from xenogeneic collagens is a special kind of collagen fibrils in vivo and plays an important role in living systems. Inspired by nature, can a HCF form in vitro? Herein, we fabricated a new HCF by neutralizing a mixture of type I bullfrog (Rana catesbeiana Shaw) skin collagen and porcine (Sus scrofa domesticus) skin collagen with a phosphate buffer, and investigated its physicochemical properties. Self-assembly kinetics and fluorescence-quenching experiments showed that a significant intermolecular interaction and co-assembly behavior occurred between bullfrog skin collagen and porcine skin collagen, thus confirming that xenogeneic collagens can self-assemble to form HCF. Differential scanning calorimetry revealed that the thermal stability of HCF was completely different from that of the syngeneic bullfrog skin and porcine skin collagen fibrils. This finding indicated that a new kind of collagen fibril was fabricated successfully. Scanning electron microscopy and transmission electron microscopy tests showed that the diameters and D-periodicity lengths of HCF were smaller than those of the syngeneic collagen fibrils, suggesting that the morphological features of HCF were distinguished from those of the syngeneic fibril samples. Moreover, viscoelasticity of a collagen gel also changed after the self-assembly of xenogeneic collagens. Meanwhile, the obtained hybrid gel still exhibited good biocompatibility and cell proliferation properties. Finding from this work provides a new idea for the improvement or regulation of collagen-based products performance.