Tensile Strength, Cellular Content and Degradation properties in three generations of concentrated growth factors

Concentrated growth factors (CGF) is a biomaterial with regenerative potential, enriched with platelets, leukocytes, growth factors, and fibrin, but it degrades within 2-3 weeks. Albumin extends CGF stability, while silver nanoparticles (SNP) improve its mechanical and antibacterial properties. This in vitro and ex vivo study investigates the impact of albumin (Alb-CGF) and albumin with SNP (Alb-CGF-SNP) on CGF's mechanical properties, degradation rate, and cellular bioactivity.

Blood samples were collected from 15 healthy volunteers who met specific inclusion criteria, with the sample size determined using G*Power software for power calculation. Three groups were prepared: control CGF, experimental Alb-CGF, and Alb-CGF-SNP. Membranes were produced using a Medifuge MF200 centrifuge and activated plasma albumin gel (APAG) device following standard settings. In experimental groups, the superficial 2.5 ml of plasma layer was heated at 75 °C for 10 min before combining with the buffy coat layer of CGF. Mechanical properties were tested using a texture analyzer, degradation rates were measured by weight loss percentage, and cellular bioactivity was evaluated with a Sysmex hematology analyzer. Data analysis was conducted using GraphPad Prism 8.0. Group differences were assessed via one-way ANOVA and Welch ANOVA, with Tukey's HSD test for post hoc paired group comparisons.

The control (CGF) showed the highest mechanical properties, with Ultimate Tensile Strength (UTS) (95.6 kPa), Modulus of Toughness (55.55 kJ/m³), and Young's Modulus (75.73 kPa; (P < 0.01). No significant differences were observed in the strain at break across groups (P > 0.90). Alb-CGF-SNP displayed superior degradation resistance, with 45.2% weight loss at day 60 versus 84.2% in CGF (P < 0.01). CGF had the highest WBC and platelet levels, with amounts of 2.25 and 3.11-fold, respectively (P < 0.01).

The modification of CGF with albumin and silver nanoparticles enhanced degradation resistance, although it did not reach the tensile strength and cellular content of unmodified CGF. Clinically, Alb-CGF and Alb-CGF-SNP serve as effective barrier membranes due to their prolonged stability, while CGF remains advantageous where high mechanical strength is required. Despite lower elasticity limiting suturing, their plasticity supports use as fillers or for tissue phenotype modification in regenerative applications.