Color-variable dual-dyed photodynamic antimicrobial polyethylene terephthalate (PET)/cotton blended fabrics.

The urgent demand for scalable, potent, color variable, and comfortable antimicrobial textiles as personal protection equipment (PPE) to help reduce infection transmission in hospitals and healthcare facilities has significantly increased since the start of the COVID-19 pandemic. Here, we explored photodynamic antimicrobial polyethylene terephthalate/cotton (TC) blended fabrics comprised of photosensitizer-conjugated cotton fibers and polyethylene terephthalate (PET) fibers dyed with disperse dyes. A small library of TC blended fabrics was constructed wherein the PET fibers were embedded with traditional disperse dyes dominating the fabric color, thereby enabling variable color expression, while the cotton fibers were covalently coupled with the photosensitizer thionine acetate as the microbicidal agent. Physical (SEM, CLSM, TGA, XPS and mechanical strength) and colorimetric (K/S and CIELab values) characterization methods were employed to investigate the resultant fabrics, and photooxidation studies with DPBF demonstrated the ability of these materials to generate reactive oxygen species (i.e., singlet oxygen) upon visible light illumination. The best results demonstrated a photodynamic inactivation of 99.985% (~ 3.82 log unit reduction, P = 0.0021) against Gram-positive S. aureus, and detection limit inactivation (99.99%, 4 log unit reduction, P ≤ 0.0001) against Gram-negative E. coli upon illumination with visible light (60 min; ~ 300 mW/cm2; λ ≥ 420 nm). Enveloped human coronavirus 229E showed a photodynamic susceptibility of ~ 99.99% inactivation after 60 min illumination (400-700 nm, 65 ± 5 mW/cm2). The presence of the disperse dyes on the fabrics showed no significant effects on the aPDI results, and furthermore, appeared to provide the photosensitizer with some measure of protection from photobleaching, thus improving the photostability of the dual-dyed fabrics. Taken together, these results suggest the feasibility of low cost, scalable and color variable thionine-conjugated TC blended fabrics as potent self-disinfecting textiles.

3-Dimentional printing of polysaccharides for water-treatment: A review.

Biological polysaccharides such as cellulose, chitin, chitosan, sodium alginate, etc., serve as excellent substrates for 3D printing due to their inherent advantages of biocompatibility, biodegradability, non-toxicity, and absence of secondary pollution. In this review we comprehensively overviewed the principles and processes involved in 3D printing of polysaccharides. We then delved into the diverse application of 3D printed polysaccharides in wastewater treatment, including their roles as adsorbents, photocatalysts, biological carriers, micro-devices, and solar evaporators. Furthermore, we assessed the technical superiority and future potential of polysaccharide 3D prints, envisioning its widespread application. Lastly, we remarked the challenging scientific and engineering aspects that require attention in the scientific research, industrial production, and engineering utilization. By addressing these key points, we aimed to advance the field and facilitate the practical implementation of polysaccharide-based 3D printing technologies in wastewater treatment and beyond.

In situ grown bacterial cellulose/MoS2 composites for multi-contaminant wastewater treatment and bacteria inactivation.

For the purpose of developing multifunctional water purification materials capable of degrading organic pollutants while simultaneously inactivating microorganisms from contaminated wastewater streams, we report here a facile and eco-friendly method to immobilize molybdenum disulfide into bacterial cellulose via a one-step in-situ biosynthetic method. The resultant nanocomposite, termed BC/MoS2, was shown to possess a photocatalytic activity capable of generating •OH from H2O2, while also exhibiting photodynamic/photothermal mechanisms, the combination of which exhibits synergistic activity for the degradation of pollutants as well as for bacterial inactivation. In the presence of H2O2, the BC/MoS2 nanocomposite exhibited excellent antibacterial efficacy upwards of 99.9999% (6 log units) for the photoinactivation of both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus upon infrared (IR) lamp illumination (100 W, 760 nm ≤ λ ≤ 5000 nm, 15 cm vertical distance; 5 min). Mechanistic studies revealed synergistic pathogen inactivation resulting from the combination of photocatalytically generated •OH and hyperthermia induced by the photothermal conversion of the near-IR light. In addition, the BC/MoS2 nanocomposite also showed excellent photodegradation activity for common aqueous contaminants in the presence of H2O2, including malachite green (a textile dye), catechol violet (a phenol) and formaldehyde. Taken together, our findings demonstrate that sustainable materials such as BC/MoS2 have potential applications in wastewater treatment and microorganism disinfection.

Riboflavin-based carbon dots with high singlet oxygen generation for photodynamic therapy.

Photodynamic therapy, as an effective treatment for superficial tumors, has attracted more and more attention. The development of safe, biocompatible and in vivo photosensitive materials is helpful to promote photodynamic therapy. Here we report green fluorescent carbon quantum dots prepared from a natural vitamin, riboflavin (VB2), as a photosensitizer. The VB2-based carbon dots have excellent water solubility and biocompatibility, and their singlet oxygen generation ability is much stronger than that of riboflavin itself. Through endocytosis, the carbon dots can easily enter the cells and show bright green fluorescence. In vivo experiments show that after photodynamic therapy the carbon dots can significantly inhibit the growth of tumors, and will not have toxic and side effects on other organs.

Synergistic Photodynamic and Photothermal Antibacterial Activity of In Situ Grown Bacterial Cellulose/MoS2-Chitosan Nanocomposite Materials with Visible Light Illumination.

Owing to the rise in prevalence of multidrug-resistant pathogens attributed to the overuse of antibiotics, infectious diseases caused by the transmission of microbes from contaminated surfaces to new hosts are an ever-increasing threat to public health. Thus, novel materials that can stem this crisis, while also functioning via multiple antimicrobial mechanisms so that pathogens are unable to develop resistance to them, are in urgent need. Toward this goal, in this work, we developed in situ grown bacterial cellulose/MoS2-chitosan nanocomposite materials (termed BC/MoS2-CS) that utilize synergistic membrane disruption and photodynamic and photothermal antibacterial activities to achieve more efficient bactericidal activity. The BC/MoS2-CS nanocomposite exhibited excellent antibacterial efficacy, achieving 99.998% (4.7 log units) and 99.988% (3.9 log units) photoinactivation of Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, respectively, under visible-light illumination (xenon lamp, 500 W, λ ≥ 420 nm, and 30 min). Mechanistic studies revealed that the use of cationic chitosan likely facilitated bacterial membrane disruption and/or permeability, with hyperthermia (photothermal) and reactive oxygen species (photodynamic) leading to synergistic pathogen inactivation upon visible-light illumination. No mammalian cell cytotoxicity was observed for the BC/MoS2-CS membrane, suggesting that such composite nanomaterials are attractive as functional materials for infection control applications.

Self-healing polyurethane-elastomer with mechanical tunability for multiple biomedical applications in vivo.

The unique properties of self-healing materials hold great potential in the field of biomedical engineering. Although previous studies have focused on the design and synthesis of self-healing materials, their application in in vivo settings remains limited. Here, we design a series of biodegradable and biocompatible self-healing elastomers (SHEs) with tunable mechanical properties, and apply them to various disease models in vivo, in order to test their reparative potential in multiple tissues and at physiological conditions. We validate the effectiveness of SHEs as promising therapies for aortic aneurysm, nerve coaptation and bone immobilization in three animal models. The data presented here support the translation potential of SHEs in diverse settings, and pave the way for the development of self-healing materials in clinical contexts.

A perfusable, multifunctional epicardial device improves cardiac function and tissue repair.

Despite advances in technologies for cardiac repair after myocardial infarction (MI), new integrated therapeutic approaches still need to be developed. In this study, we designed a perfusable, multifunctional epicardial device (PerMed) consisting of a biodegradable elastic patch (BEP), permeable hierarchical microchannel networks (PHMs) and a system to enable delivery of therapeutic agents from a subcutaneously implanted pump. After its implantation into the epicardium, the BEP is designed to provide mechanical cues for ventricular remodeling, and the PHMs are designed to facilitate angiogenesis and allow for infiltration of reparative cells. In a rat model of MI, implantation of the PerMed improved ventricular function. When connected to a pump, the PerMed enabled targeted, sustained and stable release of platelet-derived growth factor-BB, amplifying the efficacy of cardiac repair as compared to the device without a pump. We also demonstrated the feasibility of minimally invasive surgical PerMed implantation in pigs, demonstrating its promise for clinical translation to treat heart disease.