Injectable self-healing hydrogel fabricated from antibacterial carbon dots and ɛ-polylysine for promoting bacteria-infected wound healing.

Developing highly efficient pharmaceuticals to eradicate pathogens and facilitate wound healing is of great concern. Despite some cationic carbon dots (CDs) have been used for sterilization, hardly any anionic CDs with antimicrobial activity have appeared. In the present work, we engineered a string of anionic CDs (especially CD31) as valid broad-spectrum bactericides to kill bacteria. Furthermore, CD31 conjugated with ɛ-polylysine (Plys) to construct injectable, and self-healing hydrogel (CD-Plys) that possess the advantages of remarkable broad spectrum antibacterial activity, excellent wound healing ability and satisfied biocompatibility. CD-Plys could dramatically accelerate wound healing with epithelization and enhanced angiogenesis. Taken together, this work provides a two-pronged strategy to explore CDs-based antimicrobial agents for disease therapy and tissue engineering.

Graded-Band-Gap Zinc-Tin Oxide Thin-Film Transistors with a Vertically Stacked Structure for Wavelength-Selective Photodetection.

Filter-free wavelength-selective photodetectors have garnered significant attention due to the growing demand for smart sensors, artificial intelligence, the Internet of Everything, and so forth. However, the challenges associated with large-scale preparation and compatibility with complementary metal-oxide-semiconductor (CMOS) technology limit their wide-ranging applications. In this work, we address the challenges by constructing vertically stacked graded-band-gap zinc-tin oxide (ZTO) thin-film transistors (TFTs) specifically designed for wavelength-selective photodetection. The ZTO thin films with various band gaps are fabricated via atomic layer deposition (ALD) by varying the ALD cycle ratios of zinc oxide (ZnO) and SnO2. The ZTO film with a small Sn ratio exhibits a decreased band gap, and the resultant TFT shows a degraded performance, which can be attributed to the Sn4+ dopant introducing a series of deep-state energy levels in the ZnO band gap. As the ratio of Sn increases further, the band gap of the ZTO also increases, and the mobility of the ZTO TFT increases up to 30 cm2/V s, with a positive shift of the threshold voltage. The photodetectors employing ZTO thin films with distinct band gaps show different spectral responsivities. Then, vertically stacked ZTO (S-ZTO) thin films, with gradient band gaps increasing from the bottom to the top, have been successfully deposited using consecutive ALD technology. The S-ZTO TFT shows decent performance with a mobility of 18.4 cm2/V s, a threshold voltage of 0.5 V, an on-off current ratio higher than 107, and excellent stability under ambient conditions. The resultant S-ZTO TFT also exhibits obviously distinct photoresponses to light at different wavelength ranges. Furthermore, a device array of S-ZTO TFTs demonstrates color imaging by precisely reconstructing patterned illuminations with different wavelengths. Therefore, this work provides CMOS-compatible and structure-compact wavelength-selective photodetectors for advanced and integrable optoelectronic applications.

A novel aggregation-induced emission probe-linked phage sorbent assay for virulent bacteria strain imaging and on-site detection.

It was critically important to develop some sensitive, rapid, and specific imaging or detection methods for the virulent strain in food safety monitoring. In the study, a novel tetraphenyl mono-phenylboronic acid dye (TPE-PBA) with good aggregation-induced emission (AIE) features and high combining capacity towards bacteria was first synthesized. With TPE-PBA as a signal tag, a sandwich-type AIE probe-linked phage sorbent assay was developed for imaging and detecting virulent strains using Escherichia coli O157:H7 (E. coli O157:H7) as a representative. In the assay, phages for E. coli O157:H7 were firstly fixed on the bottom of a 96-well plate to specifically capture the strain, then the TPE-PBA signal tag was added and incubated with the captured strain to produce the phage/E. coli O157:H7/TPE-PBA complex. The complex could produce intensive AIE fluorescence being proportional to the amount of E. coli O157:H7 with a detection limit of 30 CFU mL-1 within 30 min. Simultaneously, the strain could be imaged in the plate with good anti-photobleaching and AIE effects. The results demonstrated the AIE-linked phage sorbent assay with a TPE-PBA signal tag could provide a suitable platform for rapid and specific detection and imaging of virulent strains. Therefore, it exhibited good application prospects in the on-site monitoring of food pathogens.