Anisotropic Collagen Fiber Scaffolds as A Biomimetic Platform for Functional Tendon and Ligament Regeneration

Abstract

Collagen is the backbone of tendon and ligament tissue. It makes up most of the extracellular matrix and gives these structures their strength and organization. So, it makes sense to build scaffolds from collagen when trying to repair torn tendons or ligaments. But there is a catch: pure collagen on its own is rarely strong enough to handle the forces the human body throws at it, and most scaffolds lack the aligned fiber structure that native tendons depend on. In this study, we look at how researchers are designing anisotropic collagen fiber scaffolds to overcome these problems. We start by describing what tendons and ligaments actually need to survive in the body—not just tensile strength, but resistance to fatigue fracture, creep, and the surprisingly critical ability to hold a surgical suture. Then we walk through the main fabrication strategies for getting collagen fibers to line up the right way: electrospinning, braiding, 3D bioprinting, core-shell designs, and hydrogel reinforcement. Each approach has its own strengths and trade-offs. Despite some encouraging results in animal studies, collagen scaffolds are not yet ready for regular clinical use. Three stubborn barriers stand in the way: poor vascularization means the inside of the scaffold stays starved of oxygen; incomplete remodeling leaves synthetic material behind long after it should be gone; and weak host integration keeps the scaffold from truly becoming part of the living tissue. We close by laying out the design principles we believe will finally push collagen-based scaffolds from the lab into the operating room.