Scheme 2.

PRP gel preparation, exosome extraction, silk fibroin extraction, and results of blood minor crossmatch. Schematic illustration of (A) PRP extraction and PRP gel preparation, (B) PRP exosomes isolation by gradient ultracentrifugation and ultrafiltration, (C) long bone dissection and isolation of bone marrow, (D) BM-MSCs and MSC-derived exosomes isolation by gradient ultracentrifugation and ultrafiltration, (E) blood minor crossmatch, and (F) preparation of injectable silk fibroin, (G–H) rat blood sampling by cardiac puncture, (I) blood fractionation by centrifugation in EDTA tubes, (J) platelet aggregation in plasma without prostaglandin E1 after the second centrifugation step, (K) representative images for blood minor crossmatch. The absence of clumping in the six-well plate and hemolysis in tubes indicated that the donor's PRP was compatible with the recipient's.