Amino acid-derived Poly(L-Lysine) (p(LL)) microgel as a versatile biomaterial: Hydrolytically degradable, drug carrying, chemically modifiable and antimicrobial material

Here, a microgel of poly((L)-Lysine) (p(LL)) from an amino acid,(L)-Lysine, was synthesized by microemulsion technique using AOT as surfactant in gasoline. The prepared p(LL) microgel was shown to be hydrolytically degradable at pH values of 5.4, 7.4, and 9 in phosphate buffer solution (PBS). The protonated p(LL) microgel was loaded with model drugs such as naproxen and riboflavin and found to release about 80% of loaded naproxen in 180 minutes and 70% of loaded riboflavin in about 120 minutes suggesting the potential of p(LL) microgels to act as fast drug delivery vehicles. Furthermore, p(LL) microgels were chemically modified with 1-bromoethane (BE), 1-bromooctane (BO), and 1-bromoethylamine (BEA) to render antimicrobial capabilities. It was found that protonated p(LL) microgels had 29 +/- 1 mm inhibition zone diameter forPseudomonas aeruginosaATCC 10145. Furthermore, minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) values forStaphylococcus aureusATCC 6538 were also calculated as 1 and 2.5 mg/mL concentrations, respectively, for protonated p(LL) microgels.