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Osteomyelitis is a severe bone condition caused by bacterial infection that can lead to lifelong disabilities or fatal sepsis. Given that the infection is persistent and penetrates deep into the bone tissue, targeting and rapidly treating osteomyelitis remain a significant challenge. Herein, a triblock targeting peptide featuring ROS-cleavable linkage/antibacterial/bone-targeting unit was grafted onto the macrophage-derived exosomes (RAB-EXO). In vitro, the effective eradication of osteomyelitis pathogens MRSA/E. coli and induction of M2 macrophage differentiation were triggered by RAB-EXO. In vivo, after the intravenous administration of RAB-EXO, it can target the bone tissue and release antimicrobial peptides in the high ROS environment of osteomyelitis. The released antimicrobial peptides markedly inhibit bacterial growth at the infection sites. Moreover, M2 differentiation of the bone tissue macrophages are facilitated by EXO, thereby decreasing the inflammatory factors and achieving the anti-inflammatory effect. Finally, the complete healing of osteomyelitis without adverse effects associated with traditional treatments is achieved within 28 days in rat models. Our findings confirm that RAB-EXO, as a targeted treatment for osteomyelitis, offers promising directions for addressing other bacterial infection diseases, such as periodontitis and rheumatoid arthritis, through similar mechanisms. [ABSTRACT FROM AUTHOR]

The enhancement of photocatalytic semiconductor degradation performance through a bismuth‐rich strategy and heterojunction engineering is considered a very effective approach. Herein, the bismuth‐rich Bi3O4Cl/BixOyIz composites are synthesized through a simple solvothermal reaction. The composites have an internal electric field because of their specific layered structure. Due to the difference between their covalent [BixOy]2+ layer and exchangeable halogen ion layer, the enhanced internal electric field facilitates electron transfer at the high‐quality interface of the semiconductor. The trace presence of Bi3O4Cl/BixOyIz (0.1 g L−1) can achieve an 88% removal of tetracycline (20 mg L−1) from the solution phase under visible light illumination in 120 min. The photocatalytic activity is much higher than that of pure BiOCl and BiOI. Furthermore, the material also exhibits high photocatalytic degradation performance for bisphenol A, doxycycline hydrochloride, etc. The excellent results further confirm the application range of the prepared photocatalysts. The superior photocatalytic activity of Bi3O4Cl/BixOyIz is attributed to the formation of a heterojunction and the generation of an internal electric field, which enhances charge separation and oxidation ability. Photoelectrochemical characterization can confirm the above views. Free radical trapping experiments and electron spin resonance show that heterojunctions can produce abundant •O2− and •OH under visible light irradiation. [ABSTRACT FROM AUTHOR]

Though heterogeneous Fenton-like reactions possess various characteristics such as a wide application range and mild reaction conditions, their reactivity is currently restricted by unsatisfactory H2O2 decomposition efficiency and low pH adaptation. Hence, Bi25FeO40 nanoparticles prepared via the mechanical ball-milling method (Bi25FeO40-B) with extensive oxygen vacancies possess high reactive oxygen species production performance by enhancing the H2O2 decomposition for tetracycline hydrochloride oxidation and Cr-(VI) reduction. H2O2 decomposition efficiency can reach 55.3% in the presence of the Bi25FeO40-B catalyst, which is much higher than that of Bi25FeO40 prepared by the traditional hydrothermal method (23.8%). The Bi25FeO40-B/H2O2 heterogeneous Fenton system demonstrates efficient performance for simultaneous oxidation of tetracycline hydrochloride (TCH) and reduction of Cr-(VI). It is capable of removing 75.2% of 50 mg/L TCH and 93.0% of 20 mg/L Cr-(VI) at pHinitial = 7, respectively. Abundant oxygen vacancies on the surface of Bi25FeO40-B nanoparticles due to the nanometer size effect can accelerate the decomposition of H2O2 to promote the formation of reactive oxygen species for removing the target organic pollutants and reduction of Cr-(VI). Consequently, this work provides a strategy for the preparation of oxygen-rich Bi25FeO40 catalysts for efficient degradation of contaminants and depicts the bright future of Fe-based metal oxides with oxygen vacancies on H2O2 activation in Fenton-like reactions. [ABSTRACT FROM AUTHOR]

A photoelectrochemical (PEC) aptasensor was designed and constructed by Bi24O31Cl10/BiOCl heterojunction as a photoelectric active material for realizing the determination of trace ciprofloxacin (CIP) in water. Compared with Bi24O31Cl10, Bi24O31Cl10/BiOCl heterojunction possessed the improvement of light harvesting and the enhancement of photocurrent signal. The formation of heterojunction between Bi24O31Cl10 and BiOCl can accelerate the transportation efficiency and inhibit the recombination rate of photoinduced carriers. Based on the excellent PEC performance, CIP aptamer was introduced on the modified Bi24O31Cl10/BiOCl/indium tin oxide (ITO) electrode for fabricating a PEC aptasensor. Owing to the combination between aptamer and CIP, CIP-aptamer complex can block the transfer of charge, leading to the reduction of photocurrent response. The PEC aptasensor possessed high sensitivity with a wide detection range (5.0~1.0 × 104 ng L−1) and a low detection limit (1.67 ng L−1, S/N = 3). The PEC aptasensor with good selectivity and reproducibility has been applied to the determination of CIP in water. [ABSTRACT FROM AUTHOR]

A self-powered photoelectrochemical (PEC) aptamer probe is presented for the determination of oxytetracycline (OTC). The assay is based on the use of g-C3N4 and NiO nanocrystals (NCs) which form a heterojunction. The latter was prepared by two-step hydrothermal pyrolysis by using the ionic liquid 1-hydroxyethyl-3-methylimidazole chloride which functions as a morphological template to form NiO NCs. The heterojunction exhibits much better electronic conductivity, wider absorption range, higher electron-hole-separation productivity, and stronger photocurrent compared to plain g-C3N4. The heterojunction was adopted to construct a self-powered PEC aptamer probe for OTC detection. An OTC-binding aptamer was immobilized on the heterojunction and the probe was constructed. The aptamer on the probe binding with OTC can form steric hindrance for transmitting of electrons and cause the PEC signal change depending on the OTC concentration. The photocurrent decreases with increasing OTC concentration in the 0.01 to 100 nM concentration range and its detection limit is 4 pM (at S/N = 3). [ABSTRACT FROM AUTHOR]

Global warming and heavy metal pollution pose tremendous challenges to human development, and photocatalysis is considered to be an effective strategy to solve these problems. Herein, copper(II) tetra (4-carboxyphenyl) porphyrin (CuTCPP) molecules were successfully in situ loaded onto Bi 4 O 5 Br 2 by a hydrothermal approach. A series of experimental results show that the light absorption capacity and photogenerated carrier separation efficiency were synchronously enhanced after the construction of CuTCPP/Bi 4 O 5 Br 2 composites. Hence, the as-prepared composites possess significantly improved photocatalytic ability for both CO 2 and Cr(VI) reduction. Specifically, CuTCPP/Bi 4 O 5 Br 2 -2 achieves a CO generation rate of 17.14 μmol g -1 under 5 h irradiation, which is twice as high as that of Bi 4 O 5 Br 2 (8.57 μmol g -1 ). Besides, the optimized CuTCPP/Bi 4 O 5 Br 2 -2 also exhibits a removal rate of 61.87% for Cr(VI) within 100 min under irradiation. Furthermore, the mechanism of CO 2 and Cr(VI) photoreduction was explored by in situ Fourier transform infrared spectroscopy and capture experiments, respectively. This work can be a reference toward the construction of photocatalysts with high activity for solar energy conversion.

As a broad-spectrum tetracycline antibiotic, the overuse of oxytetracycline (OTC) causes antibiotics residues in the environment and seriously threats to human health owing to effective antibacterial properties. Thus, it is particularly important to design a photoelectrochemical (PEC) aptasensor to detect OTC with excellent performance. Herein, we developed a selective and stable PEC aptasensor of OTC on the basis of Co 3 O 4 nanoparticles (Co 3 O 4 NPs)/graphitic carbon nitride (g-CN) heterojunction, used as PEC active materials. The Co 3 O 4 NPs were successfully grown on the g-CN via grinding and calcining mixture of Co 3 O 4 precursors and bulk g-CN. The Co 3 O 4 /g-CN heterojunction with improved light utilization and promoted electrons/holes separation capability can exhibit higher PEC signal than that of g-CN. In order to implement the purpose of specific recognition, OTC-aptamer was introduced into modified electrode to construct highly selective PEC aptasensor for OTC determination, which can possess wide linear range (0.01-500 nM) with low detection limit (3.5 pM, S/N = 3). This PEC aptasensor platform with excellent selectivity and high stability can provide a practical application in the field of water monitoring., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)