Fabrication of compositionally and topographically complex robust tissue forms by 3D-electrochemical compaction of collagen

Abstract

Collagen solutions are phase-transformed to mechanically robust shell structures with curviplanar topographies using electrochemically induced pH gradients. The process enables rapid layer-by-layer deposition of collagen-rich mixtures over the entire field simultaneously to obtain compositionally diverse multilayered structures. In-plane tensile strength and modulus of the electrocompacted collagen sheet samples were 5200 -fold and 2300 -fold greater than that of uncompacted collagen samples. Out of plane compression tests showed 27 -fold and fold increase in compressive stress and 46 -fold increase in compressive modulus compared to uncompacted collagen sheets. Cells proliferated 4.9 times faster, and cellular area spread was 2.7 times greater on compacted collagen sheets. Electrocompaction also resulted in 2.9 times greater focal adhesion area than on regular collagen hydrogel. The reported improvements in the cell-matrix interactions with electrocompaction would serve to expedite the population of electrocompacted collagen scaffolds by cells. The capacity of the method to fabricate nonlinear curved topographies with compositional heterogeneous layers is demonstrated by sequential deposition of collagenhydroxyapatite layer over a collagen layer. The complex curved topography of the nasal structure is replicated by the electrochemical compaction method. The presented electrochemical compaction process is an enabling modality which holds significant promise for reconstruction of a wide spectrum of topographically complex systems such as joint surfaces, craniofacial defects, ears, nose or urogenital forms.

Heparinized collagen sutures for sustained delivery of PDGF-BB: Delivery profile and effects on tendon-derived cells In-Vitro

“…To the best of our knowledge, load-bearing growth factor conjugated pure collagen sutures have not been used for repair of lacerated tendons. Our group has developed electrochemical compaction and alignment of collagen molecules as a powerful method to obtain load-bearing collagen threads [25-28]. Such compaction and alignment has also been shown to induce tenogenic differentiation of mesenchymal stem cells [25, 29].…”

Effects of substrate stiffness on the tenoinduction of human mesenchymal stem cells

“…Collagen sheet was fabricated in sheet form by electrocompaction method described before 20, 23 . Briefly, a 30×10×1.5 mm rectangular window was cut in a plastic piece.…”

Collagen Substrate Stiffness Anisotropy Affects Cellular Elongation, Nuclear Shape, and Stem Cell Fate toward Anisotropic Tissue Lineage

“…Electrocompaction of collagen in the sheet form was carried out as described before . Briefly, a rectangular window of 30 × 10 × 1.5 mm was cut in a plastic piece.…”

“…To the best of our knowledge there is no study which introduces SA directly to the pure collagen substrate by incorporating different stiffness values in different material directions and studies the effect on cytoskeletal response and differentiation toward anisotropic tissue lineage. Our research group demonstrated transformation of monomeric collagen solutions to solid phase by electrochemical gradients induced by linear electrodes . The method generates highly dense and aligned collagen threads with a packing density (1030 mg mL −1 ) one of the highest reported to date .…”