Polyelectrolyte-Surfactant Complex Nanofibrous Membranes for Antibacterial Applications.

Polyelectrolyte-surfactant complexes (PESCs) have garnered significant attention due to their extensive range of biological and industrial applications. Most present applications are predominantly used in liquid or emulsion states, which limits their efficacy in solid material-based applications. Herein, pre-hydrolyzed polyacrylonitrile (HPAN) and quaternary ammonium salts (QAS) are employed to produce PESC electrospun membranes via electrospinning. The formation process of PESCs in a solution is observed. The results show that the degree of PAN hydrolysis and the varying alkyl chain lengths of surfactants affect the rate of PESC formation. Moreover, PESCs/PCL hybrid electrospun membranes are fabricated, and their antibacterial activities against both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) are investigated. The resulting electrospun membranes exhibit high bactericidal efficacy, which enables them to serve as candidates for future biomedical and filtration applications.

Ultrathin, ultralight dual-scale fibrous networks with high-infrared transmittance for high-performance, comfortable and sustainable PM0.3 filter.

Highly permeable particulate matter (PM) can carry various bacteria, viruses and toxics and pose a serious threat to public health. Nevertheless, current respirators typically sacrifice their thickness and base weight for high-performance filtration, which inevitably causes wearing discomfort and significant consumption of raw materials. Here, we show a facile yet massive splitting eletrospinning strategy to prepare an ultrathin, ultralight and radiative cooling dual-scale fiber membrane with about 80% infrared transmittance for high-protective, comfortable and sustainable air filter. By tailoring antibacterial surfactant-triggered splitting of charged jets, the dual-scale fibrous filter consisting of continuous nanofibers (44 ± 12 nm) and submicron-fibers (159 ± 32 nm) is formed. It presents ultralow thickness (1.49 µm) and base weight (0.57 g m-2) but superior protective performances (about 99.95% PM0.3 removal, durable antibacterial ability) and wearing comfort of low air resistance, high heat dissipation and moisture permeability. Moreover, the ultralight filter can save over 97% polymers than commercial N95 respirator, enabling itself to be sustainable and economical. This work paves the way for designing advanced and sustainable protective materials.

Silane-functionalized polyionenes-coated cotton fabrics with potent antimicrobial and antiviral activities.

Bacterial and viral infections are posing a huge burden on healthcare industry. Existing antimicrobial textiles that are used to prevent infection transmission are lack of durability and antiviral activity. Here, we report on silane-functionalized polyionenes-coated cotton textiles with durable potent antimicrobial and antiviral activities. To obtain silane-functionalized polyionenes, silane group-containing monomers were synthesized and used to polymerize with co-monomers. These polyionenes were then conjugated onto the surface of cotton fabrics via covalent bonds. These polymers demonstrated broad-spectrum antimicrobial activity against various types of pathogenic microbes as evidenced by low effective concentration. The fabrics coated with these polymers exhibited potent bactericidal (>99.999%) and virucidal (7-log PFU reduction) activities. In addition, the antimicrobial efficacy was still more than 92% even after 50 times of washing. Evaluation of cytocompatibility and skin compatibility of the polymer-coated cotton fabrics in mice revealed that they were compatible with cells and mouse skin, and neither erythema nor edema was found in the area that was in contact with the polymer-coated fabrics. The silane-functionalized polyionenes are potentially promising antimicrobial and antiviral coating materials for textiles and other applications to prevent microbial and viral infections.

Electrospun nanofibers of polyelectrolyte-surfactant complexes for antibacterial wound dressing application.

The development of polyelectrolyte-surfactant complexes (PESCs) has attracted extensive research interest in different fields of applications. However, the liquid state of PESCs has limited their utility in applications where solid materials are required. In this study, novel antibacterial fibers were fabricated via electrospinning PESCs in the solid state without any additives. The PESCs were prepared in aqueous mixtures of pre-hydrolyzed polyacrylonitrile (HPAN), a polyelectrolyte, and cetyltrimethyl ammonium chloride (CTAC), an antibacterial cationic surfactant, by taking advantage of the self-aggregation behavior of the polyelectrolyte and surfactant, which increased the antibacterial agent loading ability and, thus, the antibacterial activity of polymers. By release-killing and contact-killing mechanisms, the as-spun PESC nanofibrous membranes exhibited strong antibacterial ability against both Gram-positive and Gram-negative bacteria, killing 5 log CFU of E. coli and S. aureus within a contact time as short as 30 min. Furthermore, PESCs were blended with polycaprolactone (PCL) to prepare composite nanofibrous membranes as a novel wound dressing, which showed excellent antibacterial activity and favorable cytocompatibility, with the mechanical strength high enough to satisfy the clinical application requirements. The PESC fibers with durable antibacterial activity presented in the current work would be promising for medical applications.

Facile synthesis of N-halamine-labeled silica-polyacrylamide multilayer core-shell nanoparticles for antibacterial ability.

Silica-polymer antimicrobial composites with a core-shell nanostructure are often prepared through a polymeric process. However, it is difficult to control the polymerization degree of the polymers to give a uniform size distribution. In this article, we present a facile approach to produce antimicrobial silica@polyacrylamide (SiO2@PAM) core-shell nanoparticles, which were synthesized via an electrostatic self-assembly method using acyclic N-halamine polymeric polyacrylamide. The morphologies and structures of these as-prepared nanoparticles were characterized by different techniques. And their antibacterial performance against both Gram-positive bacteria and Gram-negative bacteria was also evaluated. Based on the preliminary results, these core-shell nanosized spheres were made of an outer polymer shell which decorated the inner SiO2 core, showing the encapsulation of silica nanoparticles with PAM polymers. After chlorination, the resultant nanosized particles displayed a powerful and stable bactericidal capability toward both of the two model bacterial species. Bactericidal assessment further suggested a coordinated effect of the well-known antibacterial performance of N-halamines and the flocculation of PAM on the antibacterial behavior. The in vitro cytotoxicity of the prepared nanoparticles with varying concentrations was studied using mouse fibroblast cells (L929). The CCK-8 assay revealed that the SiO2@PAM composites possessed a non-cytotoxic and favorable response to the seeded cells in vitro. These results indicate the suitability of the SiO2@PAM composite particles for controlling biocidal activity, demonstrating their potential applications in deactivating bacteria or even disease control.