Space-Confined Synthesis of Thin Polypyrrole Nanosheets in Layered Bismuth Oxychloride for a Photoresponse Antibacterial within the Near-Infrared Window and Accelerated Wound Healing

Modification of traditional composite nonwovens with stable storage of light absorption transients and photodynamic antibacterial effect

Combining photodynamic antimicrobials with nonwovens is prospective. However, common photosensitizers still have drawbacks such as poor photoactivity and the inability to charge. In this study, a photodynamic and high-efficiency antimicrobial protective material was prepared by grafting bis benzophenone-structured 4,4-terephthaloyl diphthalic anhydride (TDPA) photosensitizer, and antimicrobial agent chlorogenic acid (CA) onto spunbond-meltblown-spunbond (SMS) membranes. The charging rates for ·OH and H2O2 were 6377.89 and 913.52 μg/g/h. The light absorption transients structural storage remained above 69% for 1 month. High electrical capacity remained after seven cycles indicating its rechargeability and recyclability. The SMS/TDPA/CA membrane has excellent bactericidal performance when under illumination or lightless conditions, and the bactericidal efficiency of Escherichia coli and Staphylococcus aureus reached over 99%. The construction of self-disinfection textiles based on the photodynamic strategies proposed in this paper is constructive for expanding and promoting the application of textile materials in the medical field.

Recent Progress of Photothermal Therapy Based on Conjugated Nanomaterials in Combating Microbial Infections

Photothermal therapy has the advantages of non-invasiveness, low toxicity, simple operation, a broad spectrum of antibacterial ability, and non-proneness to developing drug resistance, which provide it with irreplaceable superiority in fighting against microbial infection. The effect of photothermal therapy is closely related to the choice of photothermal agent. Conjugated nanomaterials are potential candidates for photothermal agents because of their easy modification, excellent photothermal conversion efficiency, good photostability, and biodegradability. In this paper, the application of photothermal agents based on conjugated nanomaterials in photothermal antimicrobial treatment is reviewed, including conjugated small molecules, conjugated oligomers, conjugated polymers, and pseudo-conjugated polymers. At the same time, the application of conjugated nanomaterials in the combination of photothermal therapy (PTT) and photodynamic therapy (PDT) is briefly introduced. Finally, the research status, limitations, and prospects of photothermal therapy using conjugated nanomaterials as photothermal agents are discussed.

Adhesive Composite Microspheres with Dual Antibacterial Strategies for Infected Wound Healing

Skin damage and infection pose a severe challenge to human health. Construction of a novel versatile dressing with good anti-infection and healing-promoting abilities is greatly expected. In this paper, nature-source-based composite microspheres with dual antibacterial mechanisms and bioadhesive features by microfluidics electrospray for infected wound healing is developed. The microspheres enable sustained release of copper ions, which not only show long-term antibacterial properties, but also play important role in wound-healing-related angiogenesis. Additionally, the microspheres are coated with polydopamine via self-polymerization, which renders the microspheres adhesive to the wound surface, and further enhance the antibacterial ability through photothermal energy conversion. Based on the dual antibacterial strategies provided by copper ions and polydopamine as well as the bioadhesive property, the composite microspheres exhibit excellent anti-infection and wound healing performances in a rat wound model. These results, along with the nature-source-based composition and biocompatibility, indicate the great potential of the microspheres in clinical wound repair.

Research on the Antibacterial Properties of MXene-Based 2D-2D Composite Materials Membrane

Novel MXene-based two-dimensional (2D) membranes are widely used for water purification due to their highly controllable structure and antibacterial properties. However, in the process of membrane separation, the problems of membrane fouling, especially biological fouling, limits the further application of MXene-based membranes. In this study, in order to improve the antibacterial and separation properties of membranes, three kinds of MXene-based 2D-2D composite membranes (M2~M4) were prepared using polyethersulfone (PES) as the substrate, which were GO@MXene, O-g-C₃N₄@MXene and BiOCl@MXene composite membranes respectively. The results showed that the antibacterial activity of M2~M4 against Escherichia coli and Staphylococcus aureus was further improved, especially the antibacterial ratio of M4 against Escherichia coli and Staphylococcus aureus was up to 50% and 82.4%, respectively. By comparing the surface morphology of MXene membrane and modified membrane treated bacteria through scanning electron microscopy (SEM), it was found that the cell density on modified membrane was significantly lower than that of pure MXene membrane.

Efficient Near-Infrared Response Antibacterial Ceramics Based on the Method of Facile In Situ Etching Upconversion Glass-Ceramics

As the world is faced with the coronavirus disease 2019 (COVID-19) pandemic, photocatalytic antibacterial ceramics can reduce the consumption of disinfectants and improve the safety of the public health environment. However, these antibacterial ceramics are often limited by poor stability and low light utilization efficiency. Herein, an antibacterial ceramic was developed via the method of facile in situ etching of upconversion glass-ceramics (UGC) (FIEG) with HCl, in which the BiOCl nanosheets were in situ grown on the surface of GC to improve its stability and antibacterial activity. The results suggest that the upconversion antibacterial ceramics can harvest and utilize near-infrared (NIR) photons efficiently, which display notable antibacterial activity for Escherichia coli (E. coli) under NIR (≥780 nm) and visible light (420-780 nm) irradiation, with a maximum inactivation rate of 7.5 log in 30 min. Meanwhile, in the cycle experiment, more than 6 log inactivation of E. coli was achieved using an antibacterial ceramic sheet after 2-h NIR light irradiation, and the stability of the antibacterial ceramic was discussed. Furthermore, the reactive species, fluorescence-based live/dead cells, and cell structure of bacteria were analyzed to verify the antibacterial mechanism. This study provides a promising strategy for the construction of efficient and stable antibacterial ceramics.

Targeted Wolfram-Doped Polypyrrole for Photonic Hyperthermia-Synergized Radiotherapy

Single ionizing radiation at a tolerable dose is ineffectual in eliminating malignancies but readily generates harmful effects on surrounding normal tissues. Herein, we intelligently fabricated novel wolfram-doped polypyrrole (WPPy) through a simple oxidative polymerization method with WCl₆ as an oxidizing catalyst, which possessed good biocompatibility, high photothermal conversion, and intensive radiosensitivity capacities to concurrently serve as a photothermal reagent and a radiosensitizer for hyperthermia-synergized radiotherapy (RT) against a malignant tumor. In comparison with traditional polypyrrole without noble metal doping, the innovative introduction of WCl₆ not only successfully launched the polymerization of a pyrrole monomer but also endowed WPPy with additional radiosensitization. More importantly, after further decoration with an active targeted component (SP94 polypeptide), the obtained WPPy@SP94 significantly increased tumor internalization and accumulation in vitro and in vivo and induced obvious DNA damage as well as robust ROS generation under X-ray irradiation, which meanwhile synergized with strong photonic hyperthermia to effectively inhibit tumor growth by single drug injection. Moreover, such biocompatible WPPy@SP94 showed negligible adverse effects on normal cells and tissues. WPPy@SP94 developed in this study not only expands the category of polypyrrole chemical syntheses but also sheds light on WPPy@SP94-based radiosensitizers for cancer RT.

A metal–organic framework nanocomposite with oxidation and near-infrared light cascade response for bacterial photothermal inactivation

Photothermal treatment is an effective and precise bacterial disinfection method that can reduce the occurrence of bacterial drug resistance. However, most conventional photothermal treatment strategies have the problem that the photothermal response range does not match the infection area. Herein, a metal–organic framework (MOF) nanocomposite responding to the oxidation state of the bacterial infection microenvironment was constructed for near-infrared (NIR) photothermal bacterial inactivation. In this strategy, the MOF was used as a nanocarrier to load tetramethylbenzidine (TMB) and horseradish peroxidase (HPR). The high oxidation state of the bacterial infection microenvironment can trigger the enzyme-catalyzed reaction of the nanocomposite, thereby generating oxidation products with the NIR photothermal effect for bacterial disinfection. The synthesis and characterization of the nanocomposite, oxidation state (H₂O₂) response effect, photothermal properties, and antibacterial activities were systematically studied. This study provides a new idea for building a precision treatment system for bacterial infection.