Multifunctional CdSNPs@ZIF-8: Potential Antibacterial Agent against GFP-Expressing Escherichia coli and Staphylococcus aureus and Efficient Photocatalyst for Degradation of Methylene Blue

Abstract

Multifunctional novel core–shell composites, CdSNPs@ZIF-8, have been synthesized by in situ encapsulation of different amounts of CdSNPs (150, 300, and 500 μL suspension of CdSNPs in methanol) in ZIF-8 at room temperature. These composites have been characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), and diffuse reflectance spectroscopy techniques and Brunauer–Emmett–Teller surface analysis. XPS and HRTEM indicate the encapsulation of CdSNPs within ZIF-8 crystal without disturbing the crystal order of ZIF-8. The average size of embedded CdSNPs (determined by the particle size distribution from HRTEM) is found to be 16.34 nm. CdSNPs@ZIF-8 showed potential to be used as an antibacterial agent against the broad spectrum of bacterial strains such as Gram-positive Staphylococcus aureus and Gram-negative green fluorescent protein-expressing Escherichia coli in aqueous medium, as evident by various biophysical experiments, viz., 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, optical density and fluorescence spectroscopic studies, fluorescence and optical microscopic image analysis, disk diffusion assay, field emission scanning electron microscopy, and flow cytometry for reactive oxygen species induction assay. Further, the composite has been used as an efficient photocatalyst for the degradation of organic pollutants, such as methylene blue dye, in aqueous medium and found that the core–shell composite, CdSNPs@ZIF-8 (150 μL) (abbreviated as NC-1) (5 mg), exhibited higher photocatalytic activity (≈1.8 times) than CdSNPs for degradation of 90% of methylene blue (10 mL of 10 ppm) at pH ≥ 7 due to the synergetic effect. Therefore, in situ encapsulation of CdSNPs in ZIF-8 provides an easy executable measure for purification of wastewater effluents for the effective photocatalytic degradation of organic pollutants as well as to remove the bacterial contamination under sunlight.

A novel synthesis of new antibacterial nanostructures based on Zn-MOF compound: design, characterization and a high performance application

“…The mesoporous size distribution increases the surface area of the samples, which considerably affects the antibacterial properties of the sample. Moreover, based on the BET technique, the sample has a surface area of 800 m 2 /g, which approves the interaction required for the antibacterial performance of the Zn-MOF sample [41]. Figure 3Cdepicts the SEM image of Zn-MOF having mean particle size of 97 nm.…”

Construction of 2D/2D Heterogeneous of ZIF‐8/SnS2 Composite as a Transfer of Band‐Band System for Efficient Visible Photocatalytic Activity

“…It is calculated that the potentials of the conduction band and the valence band of SnS 2 are −0.594 and 1.946 eV, and those of 2D‐ZIF‐8 are −1.088 and 3.862 eV, respectively. Due to the large difference in the forbidden band width, SnS 2 is more easily excited under visible light than 2D‐ZIF‐8, electrons in the conduction band of SnS 2 will migrate to 2D‐ZIF‐8, and holes in the valence band of 2D‐ZIF‐8 gather to SnS 2 , as shown in Figure . The electrons collected in the CB of 2D‐ZIF‐8 are sufficient ability to reduce O 2 to form •O 2 – , since the potential of CB (‐1.088 eV) is more negative than the potential of E θ (O 2 /•O 2 – )(−0.33 eV vs. NHE) .…”

“…Due to the large difference in the forbidden band width, SnS 2 is more easily excited under visible light than 2D-ZIF-8, electrons in the conduction band of SnS 2 will migrate to 2D-ZIF-8, and holes in the valence band of 2D-ZIF-8 gather to SnS 2 , as shown in Figure 8. [62] The electrons collected in the CB of 2D-ZIF-8 are sufficient ability to reduce O 2 to form * O 2 -, since the potential of CB (-1.088 eV) is more negative than the potential of E θ (O 2 / * O 2 -)(À 0.33 eV vs. NHE). [63][64][65] Unfortunately, the holes that gather to the VB of SnS 2 cannot oxidize H 2 O or OH À to * OH owing to the potential of the VB (1.946 eV) is not more positive than the potential of E θ ( * OH/H 2 O)(2.27 eV vs. NHE) and E θ ( * OH/OH À )(2.38 eV vs. NHE).…”

An NIF-doped ZIF-8 hybrid membrane for continuous antimicrobial treatment

“…14 Tet@ZIF-8@HA nanocomposites (TZH) were synthesized as a nanocarrier platform for selective/controlled release 33 of antibiotics in specic regions. According to a literature search, 15,16 although many research groups have investigated ZIF-8 nanocomposites, the instability of MOFs in water and the inherent properties of powder materials may limit their practical application. 17 Due to the inherent powder properties of MOFs, it is difficult for them to fully contact the surface of infected skin to kill bacteria; therefore, the use of MOFs alone is very inefficient.…”