Caracterização de plugs (bioscaffolds) de fibrina rica em plaquetas e leucócitos (L-PRF) obtidos a partir de um dispositivo experimental para aplicação em regeneração de defeitos ósseos

Abstract

Regenerative therapies based on autologous sources, such as leukocyte- and platelet-rich fibrin (L-PRF) plugs, represent effective and low-cost alternatives for guided bone regeneration (GBR). This study aimed to characterize L-PRF plugs obtained from a commercial device (Plugs A) and from a new device developed in this work (Plugs B), produced by additive manufacturing using stereolithography. The plugs were prepared from blood samples collected from volunteers and immediately centrifuged at 700 g for 8 minutes. The plugs were compared in terms of macroscopic features, biological composition and organization, biodegradation, microstructure, and quantification and release of TGF-β, through histological, immunohistochemical, microstructural analyses, and enzyme-linked immunosorbent assay (ELISA). The plugs were processed for hematoxylin-eosin (HE) staining. For immunohistochemical analysis, the immunoperoxidase method with dextran polymer-based technique was used, employing CD61 and TGF-β antibodies. Slides were digitized using the MoticEasyScan Pro 6 system and analyzed with DSAssistant software. Microstructural organization and biological content were examined by scanning electron microscopy (SEM). TGF-β release was quantified by ELISA at 1, 3, 7, and 14 days. Plugs B exhibited more standardized organization and greater resistance to biodegradation, with platelet concentration at the buffy coat region, along the edges, and formation of platelet aggregates in the central region. All plugs showed platelet immunostaining, with differences in distribution between Plugs A and B. Plugs B showed a significant increase in TGF-β expression at day 7. Microstructural evaluation of Plug B revealed numerous cells and platelets with preserved morphology, surrounded by a mature and organized fibrin network. In Plug A, a reduced number of cells and platelets were observed, along with loss of integrity in the fibrin network. Considering its three-dimensional configuration and cellular content, Plug B can be regarded as a bioscaffold with potential to stimulate and guide new bone formation in bone defects. The results provide a basis for future in vivo studies to evaluate the regenerative capacity of L-PRF plugs produced with the new device.