Fabrication and characterization of lysine hydrochloride Cu(ii) complexes and their potential for bombing bacterial resistance

Abstract

The emergence of drug-resistant bacteria and the lack of effective antimicrobial agents have posed a threat to public safety, so a new efficient strategy is needed to deal with the increasing severity of bacteria. Herein, a substitute antibacterial agent with high stability and biocompatibility was synthesized by incorporating lysine hydrochloride and copper sulfate pentahydrate following the liquid-phase synthesis method. The composition and structure of the Cu(ii) complex (Lys-Cu) were characterized by performing ultraviolet-visible spectrophotometry, Fourier-transform infrared spectroscopy, X-ray diffractometry (XRD), thermogravimetric analysis-differential scanning calorimetry, and single-crystal XRD. The crystal structure of Lys-Cu belongs to a monoclinic system, space group P21, with cell parameters of a = 5.14350(10), b = 16.8308(2), c = 11.4915(2) Å, Z = 2, and D = 1.548 g·cm-3. Bacteriostatic tests were carried out on Escherichia coli and Staphylococcus aureus. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of Lys-Cu against S. aureus were 0.3125 and 0.9250 mg·mL-1, respectively. The MIC and MBC values of Lys-Cu against bacterial strain E. coli were 0.4685 and 0.9250 mg·mL-1, respectively.