COVID-19-inspired "artificial virus" to combat drug-resistant bacteria by membrane-intercalation- photothermal-photodynamic multistage effects.

COVID-19 threatens human life because of the super destructiveness produced from its coronal morphology and strong transmembrane infection based on spike glycoprotein. Inspired by the coronal morphology of COVID-19 and its means of infecting, we designed an "artificial virus" with coronal morphology based on the concept of "defeating superbacteria with superviruses" by self-assembling a transacting activator of transduction peptide with triple-shell porous graphitic carbon nitride (g-C3N4) embedded with cobalt nanoparticles to forcefully infect methicillin-resistant Staphylococcus aureus (MRSA). The results confirmed that this "artificial virus" had unique properties of crossing the bacterial cell membrane barrier, heating the internal bacterial microenvironment and triggering ROS outbreak, based on its coronal morphology, membrane penetration, temperature-rising and heat insulation, oxidase-like activity and excellent visible-light harvesting properties. It had a high sterilization efficiency of 99.99% at 20 min, which was 18.6 times that of g-C3N4, and the efficiency remained at 99.99% after 3 rounds of recycling and reuse. Additionally, it can rapidly inactivate bacteria in river water and accelerate wound healing.

Enhanced functional properties of chitosan films incorporated with curcumin-loaded hollow graphitic carbon nitride nanoparticles for bananas preservation.

The exploration of novel functional packaging films is of great scientific and technological interest. Herein, a novel chitosan/hollow g-C3N4/curcumin (CS-HCNS-Cur) biocomposite films was successful fabricated with integrated functions of slow release, antimicrobial activity and food freshness preservation. CS-HCNS-Cur films take the advantages of the excellent thermal stability and slow-release ability of HCNS to curcumin. Among the characterizations including scanning electron microscopy, transmission electron microscope, atomic force microscopy, fourier transform infrared spectroscopy, mechanical properties and the rheological properties measurements confirmed the successful fabrication of CS-HCNS-Cur films. The averaged water contact angle and water vapor permeability of this film were 105.83° and 105.03 × 10-5 g·mm (m2·h·kPa)-1, respectively. This film showed pH-responsive and slow-release ability. Moreover, this film can effectively store bananas for 10 days. Therefore, CS-HCNS-Cur films have promising potential for applications in functional food packaging.

Visible light responsive, self-activated bionanocomposite films with sustained antimicrobial activity for food packaging.

The research on a new type of low-cost, less-loss and adjustable sustained antibacterial activity food packaging films with self-activation ability and great industrialization potentiality is of great scientific and technological interest. Herein, a novel chitosan/negatively charged graphitic carbon nitride self-activation bionanocomposite films was prepared by one-step electrostatic self-assembly. First, the antibacterial efficiency of this film could reach to 99.8 ± 0.26% against E. coli and 99.9 ± 0.04% against S. aureus through self-activated under visible light. Second, this film can effectively extend the shelf life of tangerines to 24 days. Hemolysis and cell experiment test proved that this film was safe and nontoxic. Finally, negatively charged graphitic carbon nitride with low-cost can improve the mechanical, thermal and hydrophobic properties of neat chitosan films. This work can provide a new pathway for the preparation of low-cost packaging films with excellent visible light responsive property and sustainable antibacterial activity.