Polymer Fiber Braiding
Bihan Chen                                          BME 240: Introduction to Clinical Medicine
One of the attempt at a proper tissue-engineered graft was the use of polymer fiber braiding. The graft must possess mechanical properties  similar to the ACL so researchers combined techniques of polymer fiber braiding and twisting to design a novel poly l-lactic acid (PLLA) scaffold. The scaffold is designed to mimic the biomechanical profile and properties of the ACL. In a study done by Freeman et al., braid-twist scaffolds were constructed and compared to braided scaffolds and twisted fiber scaffolds individually.
           Their conclusion was that the addition of fiber twisting to the braided scaffold resulted in a significant increase in the ultimate tensile strength (Su), an increase in ultimate strain [freeman, et al]. Thus, the braid-twist scaffold could pose to be a promising construct for tissue engineering of the ACL although still no where close to possessing the mechanical properties required to completely imitate the ACL.
            The figure shows the schematic for how the braids were designed: