Enhanced Cell Adhesion Properties of a Collagen-Mimicking Peptide Through Site-Specific L-DOPA Incorporation

Collagen, a key structural protein in the extracellular matrix (ECM), provides essential physical and biological support for cells, making it indispensable in tissue engineering (TE). Producing collagen-mimicking polypeptides (CMPs) in E. coli offers advantages such as rapid production, cost efficiency, and ease of genetic modifications. These CMPs can self-assemble into collagen fibrils, although they lack the post-translational modifications (PTMs) required for structural stability. To address this, the described E. coli system employs genetic code expansion to incorporate L-3,4-dihydroxyphenylalanine (L-DOPA) into CMPs at specific sites. The catechol side chain of L-DOPA enhances molecular structural stability, supports cellular attachment, and promotes cell growth. These CMPs form a triple-helix structure and self-assemble in vitro to construct collagen fibrils, with the inclusion of L-DOPA significantly enhancing the fibrillation process. The CMPs are biocompatible, enabling the spreading and increased metabolic activity of human fibroblasts cultured on 2-D hydrogels or within 3-D scaffolds, contingent on the presence of L-DOPA-incorporated CMPs. This system allows for precise genetic modifications, incorporating non-canonical amino acids to customize CMP properties for diverse TE applications. This innovative strategy merges TE and synthetic biology to improve collagen-based biomaterials, providing custom-made solutions.