Incorporating platelet-rich plasma with braided silk fibroin scaffolds to engineer artificial anterior cruciate ligament

Every year thousands of people injure their ligaments, requiring surgical intervention to return to pre-injury lifestyle. If the injury results in a complete tear of the anterior cruciate ligament (ACL), then surgical intervention will be required. The overall aim of this project is to design an artificially manufactured ligament scaffold that mimics the mechanical and biological properties of native ligament tissue using electrospun silk fibroin as the primary biomaterial.;Raw silk derived from silkworm cocoons was purified and processed to remove sericin, leaving behind pure silk fibroin. Silk fibroin fibers were then drawn and twisted into yarns. The yarns were further braided into 3-strand braids. Separately, a solution of 10% w/v silk fibroin in hexafluoropropanol (HFP) was electrospun. The 3-strand braids and the electrospun silk were soaked in platelet-rich plasma (PRP). The electrospun sheet was then wrapped around the 3-strand braid to create a composite scaffold. Other composites were created by using alginate instead of PRP or electrospinning silk directly onto the braid. These scaffolds were then mechanically tested and imaged using an scanning electron microscope (SEM). Furthermore; cells were seeded onto these scaffolds to test for proliferation and hydroxyproline production.;The results indicated that braiding the silk fibroin greatly increases the mechanical strength and toughness of the scaffold in comparison to electrospun silk. The SEM images also show that a composite scaffold can be successfully created using PRP and alginate. It was also determined that the braided silk fibroin/electrospun silk fibroin/alginate composite scaffold had very little to no pores in comparison to other electrospun scaffolds. The cell studies showed that the braided silk fibroin/electrospun silk fibroin/PRP composite scaffold was capable of growing and maintaining the largest number of cells while the braided silk fibroin/electrospun silk fibroin/alginate composite grew the least number of cells. The hydroxyproline assay results showed that the PRP composite scaffold produced the greatest concentration of hydroxyproline over a 28-day period while the alginate composite scaffold produced the least. Due to these results, it can be concluded that the braided silk fibroin/electrospun silk fibroin/PRP composite scaffold is a promising solution for engineering artificial anterior cruciate ligament scaffolds.