By taking advantage of the self-polymerization of dopamine on the surface of magnetic nanospheres in weak alkaline Tris-HCl buffer solution, a facile approach was established to fabricate core-shell magnetic molecularly imprinted nanospheres towards hypericin (Fe 3 O 4 @PDA/Hyp NSs), via a surface molecular imprinting technique. The Fe 3 O 4 @PDA/Hyp NSs were characterized by FTIR, TEM, DLS, and BET methods, respectively. The reaction conditions for adsorption capacity and selectivity towards hypericin were optimized, and the Fe 3 O 4 @PDA/Hyp NSs synthesized under the optimized conditions showed a high adsorption capacity (Q = 18.28 mg/g) towards hypericin. The selectivity factors of Fe 3 O 4 @PDA/Hyp NSs were about 1.92 and 3.55 towards protohypericin and emodin, respectively. In addition, the approach established in this work showed good reproducibility for fabrication of Fe 3 O 4 @PDA/Hyp.

The design and engineering of high-performance antimicrobial agents is critical for combating antibiotic resistance. In the present study, a rapid and broad-spectrum bactericidal agent is developed based on nanocomposites consisting of cobalt-doped zinc oxide (CoZnO) nanoparticles and MoS 2 nanosheets. The CoZnO/MoS 2 nanocomposites are prepared by a facile chemical precipitation method at controlled CoZnO and MoS 2 feeds. Scanning and transmission electron microscopic measurements show that CoZnO nanoparticles (ca. 10 nm in diameter) are clustered on the MoS 2 nanosheet surface, which facilitates the charge separation of the photo-generated electron−hole pairs, leading to enhanced photodynamic antimicrobial activity. Antibacterial assays in the dark show that the CoZnO/MoS 2 nanocomposite prepared at 30 μg of MoS 2 feed (CoZnO/MoS 2 -30) exhibits the best performance among a series of samples, with minimum inhibitory concentrations of 0.25, 0.8, and 1.8 mg mL −1 toward the Gram-negative bacterium Escherichia coli, Grampositive bacterium Staphylococcus aureus and fungus Aspergillus flavus, respectively. The antibacterial performance is markedly enhanced under photoirradiation, where 94.0% inactivation of E. coli is achieved with 20 μg mL −1 CoZnO/MoS 2 -30 nanocomposite under photoirradiation (15 W, 360 nm) for 5 min. The high antibacterial activity can be ascribed to peroxidase-like photocatalytic activity that is conducive to the generation of reactive oxygen species, as evidenced in transmission electron microscopy, electron spin resonance, and intracellular glutathione oxidation measurements. The results of the present study highlight the significance of CoZnO/MoS 2 nanocomposites as potent photodynamic antibacterial agents.

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Bacterial infections are a serious threat to human health, and the development of effective antibacterial agents represents a critical solution. In this study, NH2-MIL-101­(Fe)@MoS2/ZnO ternary nanocomposites are successfully prepared by a facile wet-chemistry procedure, where MoS2 nanosheets are grown onto the MIL-101 scaffold forming a flower-like morphology with ZnO nanoparticles deposited onto the surface. The ternary composites exhibit a remarkable sterilization performance under visible light irradiation toward both Gram-negative and Gram-positive bacteria, eliminating 98.6% of Escherichia coli and 90% of Staphylococcus aureus after exposure to visible light for 30 min, a performance markedly better than that with NH2-MIL-101­(Fe)@MoS2 binary composites and even more so than MoS2 nanosheets alone. This is ascribed to the unique electronic band structure of the composites, where the separation of the photogenerated carriers is likely facilitated by the S-scheme mechanism in the NH2-MIL-101­(Fe)@MoS2 binary composites and further enhanced by the formation of a p–n heterojunction between MoS2 and ZnO in the ternary composites. This interfacial charge transfer boosts the effective production of superoxide radicals by the reduction of oxygen, and the disproportionation reaction with water leads to the formation of hydroxy radicals, as attested in spectroscopic and microscopic measurements. Results from this study highlight the significance of structural engineering of nanocomposites in the manipulation of the electronic band structure and hence the photodynamic activity.

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