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

Abstract

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.