Enhanced Rotator-Cuff Repair Using Platelet-Rich Plasma Adsorbed on Branched Poly(ester urea)s.

Platelet-rich plasma (PRP) is a clinically relevant source of growth factors used commonly by surgeons. The clinical efficacy of PRP use as reported in the literature is widely variable which is likely attributed to poorly defined retention time of PRP at the repair site. To overcome this limitation, branched poly(ester urea) (PEU) nanofibers were used to adsorb and retain PRP at the implant site in an acute rotator-cuff tear model in rats. The adsorption of PRP to the branched-PEU 8% material was characterized using quartz crystal microbalance (QCM) and immuno-protein assay. After adsorption of PRP to the nanofiber sheet, the platelets actively released proteins. The adhesion of platelets to the nanofiber material was confirmed by immunofluorescence using a p-selectin antibody. In vivo testing using a rat rotator-cuff repair model compared five groups; no repair (control), suture repair only, repair with disc implant (Disc), repair with PRP-soaked disc (Disc PRP), and a PRP injection (PRP). Mechanical testing at 84 d for the four surgical repair groups resulted in a higher stiffness (11.8 ± 3.8 N/mm, 13.5 ± 3.8 N/mm, 16.8 ± 5.8 N/mm, 12.2 ± 2.6 N/mm, respectively) for the Disc PRP group. Histological staining using trichrome, hematoxylin, and eosin Y (H&E), and safranin O confirmed more collagen organization in the Disc PRP group at 21 and 84 d. Limited inflammation and recovery toward preoperative mechanical properties indicate PEU nanofiber discs as translationally relevant.