Methods of manufacturing collagen fibers comprising any one, a combination or all of the following: at least partially decellularizing a collagenous tissue； homogenizing the collagenous tissue； separating at least a portion of collagen fibers from the collagenous tissue； exposing the collagen fibers to an acidic solution before or after the separating； and forming at least one of a suture, a woven structure, a knitted structure, or a bioprosthetic device with the collagen fibers.
