Transparent, Robust, and Photochemical Antibacterial Surface Based on Hydrogen Bonding between a Si-Al and Cationic Dye

Transparent and visible light-activated antimicrobial air filters from electrospun crystal violet-embedded polyacrylonitrile nanofibers

Bioaerosols pose significant risks to indoor environments and public health, driving interest in advanced antimicrobial air filtration technologies. Conventional antimicrobial filters often suffer from diminished efficacy over time and require additional binders to retain antimicrobial agents. This study introduces CV@PAN, a self-disinfecting nanofiber fabricated via electrospinning of crystal violet (CV) and polyacrylonitrile (PAN). The process effectively incorporated CV into the PAN framework, minimizing environmental release. We comprehensively analyzed the physical and chemical properties of CV@PAN nanofibers, including fiber morphology, size distribution, chemical composition, thermal stability, and transparency. The CV@PAN nanofibers exhibited an average diameter of 0.28 μm. The fabricated filter achieved a bioaerosol removal efficiency of >99.2% against Staphylococcus epidermidis, with a low-pressure drop of 401.6 Pa at a face velocity of 16 cm/s. The filter demonstrated an optical transparency exceeding 50%. Upon visible light exposure, the embedded CV generated reactive oxygen species, resulting in an antibacterial efficacy of >99.9%. These findings demonstrate the significant potential of CV@PAN nanofiber filters for air quality management and their promise as an advancement in antibacterial air filtration technology.

Assembly of Dye Molecules in Covalent Organic Frameworks for Enhanced Colorimetric Biosensing

Colorimetric assays have been extensively investigated for biosensing applications due to their advantages of visual recognizability, ease of use, and low cost. However, advancing their development is a great challenge due to the inherent limitations of colorimetric dyes. Herein, we report a strategy to assemble dyes in covalent organic frameworks (COFs) to effectively reinforce the applicability of pH-responsive dyes in colorimetric bioassays. Experimental results reveal that three-dimensional COFs can promote the assembly of dyes through hydrogen bonding, resulting in the formation of a dye-supermolecule@COF assembly. Consequently, when sensitized at increased pH levels (e.g., hydroxyl ions), disruption of hydrogen bonds may trigger a rapid transition from their insoluble fixed state within the COFs into soluble, visibly detectable dye anions. This process can also be facilitated by increased hydrophilicity and elevated electrostatic repulsion between the dye anions and COFs, leading to the substantial release of chromogenic dye anions from the COF pores into the solution, thereby amplifying the colorimetric signal output. Therefore, by employing various synthesized dye-supermolecule@COFs as signal tags, we developed a colorimetric bioassay capable of accurately identifying breast cancer cell subtypes. This study not only highlights the effectiveness of dye-supermolecule@COFs in enhancing colorimetric biosensing but also underscores the potential of employing the COF-mediated dye assembly strategy for colorimetric assays.

Naphtho[1,8-ef]isoindole-7,8,10(9H)-trione as Novel Theranostic Agents for Photodynamic Therapy and Multi-Subcellular Organelles Localization

A series of naphtho[1,8-ef]isoindole-7,8,10(9H)-trione derivatives as novel theranostic agents for photodynamic therapy and multi-subcellular organelles localization were designed and synthesized. Most of them possess moderate fluorescence quantum yield and long wavelength absorption simultaneously, which made them possible for dual effects of imaging and therapy. Notably, compounds 7 b and 7 d exhibited significant light-toxicity but slight dark-toxicity. Confocal fluorescence microscopy experiments demonstrated that compound 7 b can locate and image in special multi-subcellular organelles. All the research results implied that naphtho[1,8-ef] isoindole-7,8,10(9H)-trione derivatives can be applied as a new series of theranostic agents with the characteristics of photodynamic therapy and multi-subcellular organelles imaging.

Antimicrobial and Antifouling Effects of Petal-Like Nanostructure by Evaporation-Induced Self-Assembly for Personal Protective Equipment

Although the personal protective equipment (PPE) used by healthcare workers (HCWs) effectively blocks hazardous substances and pathogens, it does not fully rule out the possibility of infection, as pathogens surviving on the fabric surface pose a substantial risk of cross-infection through unintended means. Therefore, PPE materials that exhibit effective biocidal activity while minimizing contamination by viscous body fluids (e.g., blood and saliva) and pathogen-laden droplets are highly sought. In this study, petal-like nanostructures (PNSs) are synthesized through the vertical rearrangement of colloidal lamellar bilayers via evaporation-induced self-assembly of octadecylamine, silica-alumina sol, and diverse photosensitizer. The developed method is compatible with various fabrics and imparts visible-light-activated antimicrobial and superhydrophobic-based antifouling activities. PNS-coated fabrics could provide a high level of protection and effectively block pathogen transmission as exemplified by their ability to roll off viscous body fluids reducing bacterial droplet adhesion and to inactivate various microorganisms. The combination of antifouling and photobiocidal activities results in the complete inactivation of sprayed pathogen-laden droplets within 30 min. Thus, this study paves the way for effective contagious disease management and the protection of HCWs in general medical environments, inspiring further research on the fabrication of materials that integrate multiple useful functionalities.

Performance comparison of photodynamic antimicrobial chemotherapy with visible-light-activated organic dyes: Rose bengal, crystal violet, methylene blue, and toluidine blue O

This study evaluated the photobiocidal performance of four widely distributed visible-light-activated (VLA) dyes against two bacteria (Staphylococcus epidermidis and Escherichia coli) and two bacteriophages (phages MS2 and phi 6): rose bengal (RB), crystal violet, methylene blue, and toluidine blue O (TBO). The photobiocidal performance of each dye depended on the relationship between the type of dye and microorganism. Gram-negative E. coli and the non-enveloped structure of phage MS2 showed more resistance to the photobiocidal reaction than Gram-positive S. epidermidis and the enveloped structure of phage phi 6. RB had the highest potential to yield reactive oxygen species. However, the photobiocidal performance of RB was dependent on the magnitude of the surface charge of the microorganisms; for example, anionic RB induced a negative surface charge and thus electrical repulsion. On the other hand, the photobiocidal performance of TBO was observed to be less affected by the microorganism type. The comparative results presented in our study have significant implications for selecting photodynamic antimicrobial chemotherapy (PACT) dyes suitable for specific situations and purposes. Furthermore, they contribute to the advancement of PACT-related technologies by enhancing their applicability and scalability.