Metal-Organic Framework Modified MoS2 Nanozyme for Synergetic Combating Drug-Resistant Bacterial Infections via Photothermal Effect and Photodynamic Modulated Peroxidase-Mimic Activity.

Bacterial infections have become major threats to public health all over the world. With the emergence of antibiotic resistance, it is urgent to develop novel antimicrobial materials to efficiently overcome drug resistance with high bactericidal activity. In this work, UiO-66-NH-CO-MoS2 nanocomposites (UNMS NCs) are constructed through the amidation reaction. The UNMS NCs are positively charged which is beneficial for capturing and restricting bacteria. Significantly, UNMS NCs possess a synergistic bactericidal efficiency based on near-infrared irradiation (808 nm) regulated combination of photothermal, photodynamic, and peroxidase-like enzymatic activities. Both the photodynamic property and nanozymatic activity of UNMS NCs can lead to the generation of reactive oxygen species. The UNMS NCs show high catalytic activity in a wide pH range and exhibit excellent antibacterial ability against ampicillin-resistant Escherichia coli and methicillin-resistant Staphylococcus aureus with negligible cytotoxicity. Interestingly, due to the 808 nm irradiation-induced hyperthermia in the presence of UNMS NCs, the glutathione oxidation process can be accelerated, resulting in bacterial death more easily. Mice wound models are established to further manifest that UNMS NCs can promote wound healing with good biosafety in living systems.

Crystal structure, microwave dielectric properties, and dielectric resonant antenna studies of novel low-permittivity CoAl2O4 spinel ceramics.

CoAl2O4 spinel ceramics were prepared via a standard solid-state reaction method, and their crystal structure, microwave dielectric properties, and dielectric resonant antenna applications were systematically investigated in this study. X-Ray diffraction patterns and Raman spectra confirmed that CoAl2O4 belongs to the Fd-3 m space group with cubic crystal symmetry. εr and Qf values increased with the increasing sintering temperature, where an ever-improving microstructure was also observed from the scanning electron micrographs. The optimal microwave dielectric properties were achieved as follows: εr = 9.34, Qf = 30,500 GHz, and τf = -54 ppm/°C. Moreover, a dielectric resonant antenna was designed and simulated to demonstrate the application prospects of CoAl2O4 ceramics towards microwave antennas. The CoAl2O4-based antenna resonating at 14.33 GHz exhibited a high return loss of -40.9 dB, a wide impedance bandwidth of 940 MHz, and an exceptionally high total efficiency of 96.6%. The remarkable antenna performances suggested that CoAl2O4 ceramics were promising candidates for wireless communication devices operating at the Ku-band, provided τf can be further tuned toward zero.