Dose-dependent doxycycline local drug delivery using T-PRF: preliminary in vitro study

T-PRF is an autologous platelet concentrate widely used in medicine and dentistry. Its potential as a local drug delivery system remains an area of growing interest. This study aimed to evaluate the characteristics and performance of T-PRF membranes loaded with different doses of doxycycline (0.5 mL, 1 mL, and 2 mL). T-PRF membranes were prepared from 15 healthy individuals without bleeding disorders. Each membrane was injected with one of the three doxycycline doses, and outcomes were compared with non-drug-loaded controls. Fibrin network patterns, antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, doxycycline release over time, and membrane degradation rates were assessed using light microscopy and standard microbiological methods. In this preliminary in vitro study, doxycycline-loaded T-PRF membranes exhibited lower degradation rates than unloaded controls, with the 2 mL group showing the slowest degradation (p ≤ 0.001), suggesting that higher drug loading may enhance membrane stability. Fibrin network scores were higher in all drug-loaded groups (p ≤ 0.001), indicating a denser matrix that could support sustained drug retention. All membranes demonstrated antibacterial activity against S. aureus, whereas no activity was observed against P. aeruginosa, highlighting the selective antimicrobial potential of doxycycline-loaded T-PRF membranes. Among the tested groups, the 2 mL dose produced the largest inhibition zone, reflecting the most pronounced antibacterial effect within the studied range. While these results are encouraging, they should be interpreted as preliminary observations given the in vitro design, the use of the disk diffusion method, and the semi-quantitative nature of the release data. Overall, these in vitro findings indicate that doxycycline-loaded T-PRF membranes provide selective antibacterial activity and enhanced membrane stability, suggesting that autologous T-PRF may be a promising platform for local antimicrobial delivery. Further studies are needed to confirm their effectiveness and explore controlled release under more comprehensive conditions.