A biopolymer fiber containing collagen. The biopolymer fiber has excellent ultimate tensile strength, modulus of elasticity, and strain at break comparable to native human tendons and ligaments. The fiber may substantially circular, ovoid, square, rectangular, ribbon-like, triangular, or irregularly shaped. The fiber exhibits an ordered, longitudinally-oriented structure, and the fiber allows infiltration of cellular growth. Implantable biopolymer scaffolds and sutures containing the fibers are provided as well as microfluidic and extrusion methods for producing the biopolymer fibers.
