Novel MOF-based mixed-matrix membranes, N-CQDs@[Zn(HCOO)][CHN]/PEG, as the effective antimicrobials

The purpose of this study was to prepare the affordable and novel materials as the efficient and effective antimicrobials. Therefore, the metal–organic framework (MOF) with the formula of [Zn(HCOO)][CHN], polyethylene glycol (PEG), and nitrogen-doped carbon quantum dots (N-CQDs) was chosen to synthesize the two novel mixed-matrix membranes (MMMs). [Zn(HCOO)][CHN]/PEG and N-CQDs@[Zn(HCOO)][CHN]/PEG as the novel MMMs were simply synthesized in a few steps and their antimicrobial activity was investigated against the Gram-negative bacteria, Escherichia coli (E. coli). Furthermore, a novel method was used for the synthesis of [Zn(HCOO)][CHN]. The particles were characterized by the Fourier-transform infrared spectroscopy, the X-ray powder diffraction, the CHNS elemental analysis, and the field-emission scanning electron microscopy. The cytotoxicity and antimicrobial activity of the particles were also studied. The result of MTT (methylthiazolyldiphenyl-tetrazolium bromide) assay showed that these novel MMMs have a good biocompatibility unlike the MOF ([Zn(HCOO)][CHN]) alone. Moreover, the [Zn(HCOO)][CHN]/PEG has a moderate antimicrobial activity against E. coli under the irradiation of UV or the ambient light. However, N-CQDs@[Zn(HCOO)][CHN]/PEG as the novel mixed-matrix membrane (MMM) has excellent antimicrobial activity without the presence of antibiotics which is due to its high quantum yield under the irradiation of UV light. Therefore, this research enhances the biocompatibility of [Zn(HCOO)][CHN] through producing MMM. Furthermore, the antimicrobial activity of MOF/PEG was increased in terms of cost-effectiveness by encapsulating the N-CQDs.