The development of narrow-spectrum antimicrobial agents is paramount for swiftly eradicating pathogenic bacteria, mitigating the onset of drug resistance, and preserving the homeostasis of bacterial microbiota in tissues. Owing to the limited affinity between the hydrophobic lipid bilayer interior of bacterial cells and most hydrophilic, polar peptides, the construction of a distinctive class of four-armed host-defense peptides/peptidomimetics (HDPs) is proposed with enhanced specificity and membrane perturbation capability against Pseudomonas aeruginosa by incorporating imidazole groups. These groups demonstrate substantial affinity for unsaturated phospholipids, which are predominantly expressed in the cell membrane of P. aeruginosa , thereby enabling HDPs to exhibit narrow-spectrum activity against this bacterium. Computational simulations and experimental investigations have corroborated that the imidazole-rich, four-armed peptidomimetics exhibit notable selectivity toward bacteria over mammalian cells. Among them, 4H10, characterized by its abundant and densely distributed imidazole groups, exhibits impressive activity against various clinically isolated P. aeruginosa strains. Moreover, 4H10 has demonstrated potential as an antibiotic adjuvant, enhancing doxycycline accumulation and exerting effects on intracellular targets by efficiently disrupting bacterial cell membranes. Consequently, the hydrogel composed of 4H10 and doxycycline emerged as a promising topical agent, significantly diminishing the skin P. aeruginosa burden by 97.1% within 2 days while inducing minimal local and systemic toxicity.
In recent years, all-inorganic lead halide perovskite CsPbX 3 (X = Cl, Br, I) nanocrystals as kinds of new luminescent materials have attracted more and more attentions because of their size tunable emission wavelength, narrow emission peak, high luminous efficiency and good air stability. Herein we have synthesized all-inorganic halide perovskite nanocrystals by hot-injection method and anion exchange reaction, achieving the whole visible light region from 410 to 700 nm with narrow spectral in the range of 15–40 nm. Moreover, a white light emitting diode (WLED) was constructed by stacking CsPbBr 3 QDs-ethyl acetate composite film and CaSrAlN 3 :Eu 2+ -poly (methyl methacrylate) composite film on the blue LED chip, displaying the ideal white light with the chromaticity coordination at (0.3379, 0.3432) and the color temperature of 5261 K. Because of the deep traps resulted from partial oxidation at the QDs' surface under large excitation light intensity, the WLED is not stable enough to work at a high operation current, but it can work steadily under a relatively lower operation current.
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