Peptide-AIE Nanofibers Functionalized Sutures with Antimicrobial Activity and Subcutaneous Traceability.

As one of the most widely used medical devices, sutures face challenges related to surgical site infections (SSIs) and lack of subcutaneous traceability. In the present study, a facile and effective approach using peptide-AIE nanofibers (NFs-K18) to create fluorescent-traceable antimicrobial sutures, which have been applied to four commercially available sutures is developed. The functionalized sutures of PGAS-NFs-K18 and PGLAS-NFs-K18 exhibit fluorescence with excellent penetration from 4 mm chicken breasts. They also demonstrate remarkable stability after 24 h of white light illumination and threading through chicken breasts 10 times. These sutures efficiently generate ROS, resulting in significant suppression of four clinical bacteria, with the highest antimicrobial rate of ≈100%. Moreover, the sutures exhibit favorable hemocompatibility and biocompatibility. In vivo experiments demonstrate that the optimized PGLAS-NFs-K18 suture displays potent antimicrobial activity against MRSA, effectively inhibiting inflammation and promoting tissue healing in both skin wound and abdominal wall wound models, outperforming the commercially available Coated VICRYL Plus Antibacterial suture. Importantly, PGLAS-NFs-K18 exhibits sensitive subcutaneous traceability, allowing for accurate in situ monitoring of its degradation. It is believed that this straightforward strategy offers a new pathway for inhibiting SSIs and monitoring the status of sutures.

Peptide-Engineered AIE Nanofibers with Excellent and Precisely Adjustable Antibacterial Activity.

Photosensitizers with aggregation-induced emission properties (AIEgens) can produce reactive oxygen species (ROS) under irradiation, showing great potential in the antibacterial field. However, due to the limited molecular skeletons, the development of AIEgens with precisely adjustable antibacterial activity is still a daunting challenge. Herein, a series of AIE nanofibers (AIE-NFs) based on the AIEgen of DTPM as the inner core and rationally designed peptides as bacterial recognition ligands (e.g., antimicrobial peptide (AMP) HHC36, ditryptophan, polyarginine, and polylysine) is developed. These AIE-NFs show precisely adjustable antibacterial behaviors simply by changing the decorated peptides, which can regulate the aggregation and inhibition of different bacteria. By mechanistic analysis, it is demonstrated that this effect can be attributed to the synergistic antibacterial activities of the ROS and the peptides. It is noteworthy that the optimized AIE-NFs, NFs-K18, can efficiently aggregate bacteria to cluster and kill four types of clinical bacteria under irradiation in vitro, inhibit the infection of methicillin-resistant Staphylococcus aureus (MRSA) and promote wound healing in vivo. To the authors' knowledge, this is the first report of AIE-NFs with precisely adjustable antibacterial activity, providing new opportunities for photodynamic therapy (PDT) treatment of infection.

Physically crosslinked silk fibroin/hyaluronic acid scaffolds.

Combining the properties of natural protein and polysaccharide is a promising strategy to generate bioactive biomaterials with controlled structure. Here, a new method of preparing water-insoluble silk fibroin/hyaluronic acid (SF/HA) scaffolds with tunable performances using an all-aqueous process is reported. Freezing-induced assembly was used to form silk I crystallization in the SF/HA blends. Silk I crystallization enhanced the stability of SF/HA scaffolds in water by forming silk I crystal networks to entrap blended HA without chemical cross-linking. Increasing HA content significantly enhanced the flexibility and water binding capacity of porous scaffolds, but high amount of HA reduced the water-stability of porous scaffolds due to insufficient silk I crystal cross-links. The enzymatic degradation behavior of the SF/HA scaffolds was investigated, revealing that the regulation ability of HA in the SF scaffolds. This novel nonchemically cross-linked protein/polysaccharide scaffold may be useful for soft tissue engineering due to excellent biocompatibility and tunable performances.

Effects of smoking on cognition and BDNF levels in a male Chinese population: relationship with BDNF Val66Met polymorphism.

Recent studies demonstrate that brain-derived neurotrophic factor (BDNF) might be associated with nicotine addiction, and circulating BDNF is a biomarker of memory and general cognitive function. Moreover, studies suggest that a functional polymorphism of the BDNF Val66Met may mediate hippocampal-dependent cognitive functions. We aimed to explore the relationships between smoking, cognitive performance and BDNF in a normal Chinese Han population. We recruited 628 male healthy subjects, inducing 322 smokers and 306 nonsmokers, and genotyped them the BDNF Val66Met polymorphism. Of these, we assessed 114 smokers and 98 nonsmokers on the repeatable battery for the assessment of neuropsychological status (RBANS), and 103 smokers and 89 nonsmokers on serum BDNF levels. Smokers scored lower than the nonsmokers on RBANS total score (p = 0.002), immediate memory (p = 0.003) and delayed memory (p = 0.021). BDNF levels among the smokers who were Val allele carriers were correlated with the degree of cognitive impairments, especially attention, as well as with the carbon monoxide concentrations. Our findings suggest that smoking is associated with cognitive impairment in a male Chinese Han population. The association between higher BDNF levels and cognitive impairment, mainly attention in smokers appears to be dependent on the BDNF Val66Met polymorphism.

Removing a wedge from a metallic nanodisk reveals a fano resonance.

A wide variety of complex, multicomponent plasmonic nanostructures have been shown to possess Fano resonances. Here we introduce a remarkably simple planar nanostructure, a single metallic nanodisk with a missing wedge-shaped slice, that also supports a Fano resonance. In this geometry, the Fano line shape arises from the coupling between a hybridized plasmon resonance of the disk and a narrower quadrupolar mode supported by the edge of the missing wedge slice. As a consequence, both disk size and wedge angle control the properties of the resonance. A semianalytical description of plasmon hybridization proves useful for analyzing the resulting line shape.