Preparation of macro-, micro-, and nano-sized poly(Tannic acid) particles with controllable degradability and multiple biomedical uses

Different size ranges of poly(Tannic acid) (p(TA)) particles, 2000-500 μm, 500-200 μm, 200-20 μm, and 20-0.5 μm, were successfully synthesized by using lecithin/gasoline microemulsion media. Macro, micro, and nano sized p(TA) particles were crosslinked via poly(ethylene glycol) diglycidyl ether (PEGGE) with 85 ± 7% gravimetric yield. The hydrolytic degradation of different sizes of p(TA) particles in physiological pH conditions, in pH 5.4, 7.4, and 9.0 buffer solutions at 37.5 °C, were investigated. It was found that p(TA) particles with 20-0.5 μm size distribution are more stable than the other sized particles due to the higher amounts of crosslinker used during synthesis. Furthermore, macro size p(TA) particles (2000-500 μm) were totally degraded at pH 9 within 12 days, whereas a linear and sustained degradation profile was obtained at pH 7.4 with 75 ± 4% weight loss for 24 days. The antioxidant capacity of p(TA) particles was also tested and 20-0.5 μm sized p(TA) particles demonstrated the highest antioxidant capacity with 0.1305 ± 0.0124 mg gallic acid equivalency and 145 ± 21 mM trolox equivalent g−1. It was also further demonstrated that the degraded p(TA) particles showed high antimicrobial activity against a wide spectrum of bacteria and yeast strains such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. In vitro blood compatibility of p(TA) particles was also examined by hemolysis % and blood clotting index and micrometer sized p(TA) particles are more hemocompatible with enhanced blood clotting capability. In addition, WST-1 cytotoxicity test results showed that 200-20 μm and 20-0.5 μm sized p(TA) particles were biocompatible up to 50 μg/mL concentration with 74 ± 3 and 68 ± 2% cell viabilities for L929 fibroblast cells.