Biodiverse Properties of Tannic Acid-Based Fibers

Tannic acid (TA) is a plant-based polyphenolic molecule with enticing anti-oxidant, anti-bacterial, anti-inflammatory and anti-cancer features, making it a valuable material in bio-medicinal applications. To establish whether TA-based fibers are useful tools in potential medical textiles, e.g., as wound dressing material for prophylaxis against infections and diseases, TA fibers were prepared and employed in biological assays. TA fibers were prepared with 55 weight% TA in ethanol-DI water mixture and fabricated by the electrospinning technique. Bare TA-based fibers were examined and were 1.2±0.1 % non-hemolytic and had 8.7±1.7 blood clotting index up to 2 mg/ml concentration. Degradation of bare TA-based fibers was completed in 5 minutes; however, degradation of crosslinked TA-based fibers were 98.3±2.3 % and 83.1±5.4 % for TA-Ibu and TA in 168 hours. Anti-oxidant activity of TA-based fibers was investigated by TEAC, total phenol content (TPC) and total flavonoid content (TFC) assays. Bare TA fibers possessed the highest anti-oxidant activity of 5.7±0.5 mM trolox equivalent/g, 168.0±2.0 gallic acid equivalent µg/ml and 193.0±17.0 quercetin equivalent µg/ml. Anti-bacterial activity was investigated by the disc diffusion method and the highest inhibition zone diameter was measured as 3.5±0.2 cm against S. aureus (gram +) bacteria; however, the same fiber was detected as producing 2.2±0.5 cm zone diameter for E. coli (gram -) bacteria.