The main purpose of this study was to compare A-PRF with CGF preparations to find possible differences in mechanical properties. As shown in Table 1, the sizes of A-PRF clots compressed to membranes were 8.6 ± 1.2 mm (W) × 27.5 ± 3.5 mm (L) and very similar to those of CGF clots (8.4 ± 0.8 mm × 27.6 ± 2.5 mm). As reference, PPTF membranes were also prepared by adding CaCl₂ to liquid PPP preparations using a molding glass chamber. The size of PPP membranes prepared by adding thrombin, designated PPTF in this study, was 8.3 ± 1.2 mm × 31.8 ± 2.1 mm. Furthermore, when subjected to the tensile test, both membranes could be stretched two to four times their original length. As shown in Table 2, the water content of A-PRF clots was very similar to that of CGF clots. However, PPTF clots contained significantly less amounts of water than both A-PRF and CGF clots.

Surface microstructures of various fibrin clots, including A-PRF and CGF clots, were compared, as shown in Fig. 1. Based on SEM examinations, CGF clots contained thicker fibrin fibers than A-PRF clots. PPP clots prepared by adding CaCl₂ were composed mainly of relatively thin fibers. In contrast, PPTF clots were easily distinguishable from the other three clot types and were composed of highly crosslinked fibers that were the thinnest observed.

Individual membrane types were examined by a tensile test and were characterized by three parameters: (1) Young’s modulus, (2) strain at break, and (3) maximum stress in the stress-strain curves. As shown in Fig. 2, no significant differences in both Young’s modulus and maximum stress were observed among A-PRF, CGF, and PPTF membranes. However, in strain at break, PPTF membranes were significantly inferior to CGF membranes.

Degradability of individual membrane types was examined in PBS containing trypsin and EDTA. As shown in Fig. 3, PPTF membranes degraded significantly faster than A-PRF and CGF membranes. This disparity in degradability was observed at 20 and 40 min.