Abstract
<p>Linear polyethyleneimine (L-PEI) microgel/particles were prepared using glycerol diglycidyl ether (GDE) as crosslinker at various mole ratios, 10%, 25%, and 50% of L-PEI repeating unit, and designated as L-PEI-1, L-PEI-2, and L-PEI-3, respectively. All microgels were found blood compatible with < 2% hemolysis and > 80% blood clotting indexes at 1000 mu g/mL concentrations, whereas L-PEI is hemolytic (> 80% hemolysis). Similarly, L-PEI showed cytotoxicity on L929 fibroblasts even at 50 mu g/mL, while > 80% cell viability was observed for L-PEI-based particles even at 1000 mu g/mL. Although it is regarded as less cytotoxic than branched PEI, the cross-linked L-PEI particles effectively circumvent cytotoxicity as the most important limitation of L-PEI in biological applications. Additionally, the higher antimicrobial activity against Escherichia coli, gram-negative bacteria, Bacillus subtilis, gram-positive bacteria strains, and Candida albicans, yeast strains was observed for L-PEI-1 and protonated L-PEI-1 particles. Moreover, the antibacterial activity of L-PEI-1 particles was further improved after the inclusion of Ag(I) and Cu(II) ions within L-PEI particles as Ag@L-PEI-1 and Cu@L-PEI-1 composites, respectively. The lower MIC and MBC values were determined for Ag@L-PEI-1 particles against Escherichia coli and Bacillus subtilis as 0.079 and 0.312 mg/mL, respectively, and an MFC value for Candida albicans was 0.156 mg/mL for Ag@L-PEI-1 particles.</p>
