Aligned multicompartment collagen scaffolds support stratified myoblast and fibroblast behavior for musculotendinous tissue engineering

Abstract

Injuries to musculoskeletal tissue junctions are exceedingly common and notoriously difficult to repair due to the inability to restore overlapping gradations of structural, biochemical, and mechanical signals critical to tissue interfacial integrity. This work introduces a multicompartment scaffold for muscle-tendon junction (MTJ) tissue engineering, containing distinct muscle and tendon compartments joined at a continuous interface, recapitulating the structural anisotropy, graded collagen content, and electrical excitability of the native MTJ. Collagen suspensions with or without electrically conductive poly(3,4-ethylenedioxythiophene) (PEDOT) particles representing muscle and tendon compartments respectively were carefully layered and directionally freeze-dried to form an integrated multicompartment scaffold with aligned pores mimicking the MTJ. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) confirmed the formation of a structurally anisotropic scaffold with stratified conductive polymer content, and importantly, a smooth continuous interfacial region joining the two compartments of similar scale to native MTJ. In contrast to multicompartment materials with abrupt interfaces, mechanical testing confirmed no decrease in multicompartment scaffold tensile properties relative to single compartment controls. Myoblasts and fibroblasts were successfully seeded on multicompartment scaffolds in a stratified manner while uniformly conforming to aligned scaffold contact guidance cues and maintaining metabolic activity over a week in culture. Myoblasts underwent compartment-specific differentiation while fibroblasts remained viable, even under myogenic differentiation conditions. Together, this work presents a scaffold platform integrating key structural, biochemical, and mechanical features necessary for MTJ tissue engineering.