Collagen Hybridizing Peptides Promote Collagen Fibril Growth In Vitro

Recreating the structural and mechanical properties of native tissues in vitro presents significant challenges, particularly in mimicking the dense fibrillar network of extracellular matrixes such as skin and tendons. This study develops a reversible collagen film through cycling collagen self-assembly and disassembly, offering an innovative approach to address these challenges. We first generated an engineered collagen scaffold by applying plastic compression to the collagen hydrogel. The reversibility of the collagen assembly was explored by treating the scaffold with lactic acid, leading to its breakdown into an amorphous gel─a process termed defibrillogenesis. Subsequent immersion of this gel in phosphate buffer facilitated the reassembly of collagen into fibrils larger than those in the original scaffold yet with the D-banding pattern characteristic of collagen fibrils. Transfer learning of the mobileNetV2 convolutional neural network trained on atomic force microscope images of collagen nanoscale D-banding patterns was created with 99% training and testing accuracy. In addition, extensive external validation was performed, and the model achieved high robustness and generalization with unseen data sets. Further innovation was introduced by applying collagen hybridizing peptides, which significantly accelerated and directed the assembly of collagen fibrils, promoting a more organized and aligned fibrillar structure. This study not only demonstrates the feasibility of creating a reversible collagen film that closely mimics the density and structural properties of the native matrix but also highlights the potential of using collagen hybridizing peptides to control and enhance collagen fibrillogenesis. Our findings offer promising tissue engineering and regenerative medicine strategies by enabling precise manipulation of collagen structures in vitro.