The effect of sulphur on the antibacterial properties of succinic acid-Cu(II) and mercaptosuccinic acid-Cu(II) MOFs

Abstract

Microorganism such as bacteria, virus and fungi are causing significant health problems. Here, using succinic acid (SA) and mercaptosuccinic acid (MSA) as organic ligand and Cu(II) ions as complexing agent SA-Cu(II) and MSA-Cu(II) MOFs are synthesized. The Atomic Absorption spectroscopy findings reveal that the Cu(II) ion concentration in SA-Cu(II) and MSA-Cu(II) MOFs are 168.5 ± 16 mg/mL and 340.1 ± 20 mg/mL, respectively. The prepared MOFs are characterized by using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffractometer (XRD) analysis. It is determined that SA-Cu(II) MOF is 100% crystalline, whereas the MSA-Cu(II) MOFs are found as 80% crystalline and 20% amorphous. Brunauer Emmett Teller (BET) results reveal that both of the MOFs have type IV isotherm H4 hysteresis loops. Antibacterial and antifungal properties of SA-Cu(II) and MSA-Cu(II) MOFs are tested against Escherichia coli, Pseudomona, Staphylococcus aureus, and Bacillus subtilis bacteria to determine the minimum bactericidal concentration (MBC) and minimum inhibition concentration (MIC). It is estimated that SA-Cu(II) MOFs exhibit 0.25 mg/mL MIC and MBC values, whereas MSA-Cu(II) MOFs possess 0.125 and 0.031 mg/mL MBC and MIC values, respectively on Bacillus subtilis. Interestingly, the SA-Cu(II) and MSA-Cu(II) MOFs are equally effective against S. aureus with MBC and MIC values of 0.5 and 0.25 mg/mL respectively. Finally, for the gram-negative E. coli and P. aeruginosa bacteria, the MBC and MIC values are determined as 1.0 and 0.5 mg/mL, and the MBC value of SA-Cu(II) MOF is calculated 0.5 mg/mL on E. coli.