Next Generation Antibiofilm EDTA Metal Complexes and in Vitro Cytotoxicity

Background: In this study, we synthesized ten EDTA patent pending complexes with different concentrations of metals and we also examined the cytotoxicity of EDTA complexes compared to some commercial antimicrobial wound dressings in an in vitro direct contact cytotoxic assay model.

Methods: The EDTA complexes (C1 to C10) were synthesized by the reactions of EDTA with one or two selected metal salts at pre-defined concentrations. The in vitro cytotoxicity of the complexes was measured by direct contact assay on fibroblasts (L929) and human dermal fibroblasts (HDFa). Briefly, L929 and HDFa were seeded into a 24 well plate at a concentration of 5x10(4)/ml/well. After 24 h culture, EDTA complexes were added into pre-determined wells at a concentration equivalent to the MIC against P. aeruginosa ATCC 15442. After 24 h, cell images were taken, and the cells were washed with PBS and stored at -80C. The cell viability of L929 and HDFa was measured using a commercially available CyQUANT cell proliferation assay.

Results: The cell viability of HDFa was higher than 80% after EDTA/silver/zinc treatments at MIC concentrations, which means EDTA/silver/zinc complexes are non-cytotoxic. Cell viability after treatment with all the complexes studied was higher than cell viability following treatment with other commercially available antimicrobial based wound dressings.

Conclusion: The results demonstrated that compared to many commercially available antimicrobial wound dressings, EDTA complexes are less cytotoxic. Patent pending EDTA metal ion complexes are novel and smart technologies that will form part of the next generation wound dressings as they demonstrate exceptional anti-biofilm, anti-microbial, MMP modulating and anti-inflammatory abilities.