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Since the emergence of the COVID-19 pandemic outbreak, the increasing demand and disposal of surgical masks has resulted in significant economic costs and environmental impacts. Here, we applied a dual-channel spray-assisted nanocoating hybrid of shellac/copper nanoparticles (CuNPs) to a nonwoven surgical mask, thereby increasing the hydrophobicity of the surface and repelling aqueous droplets. The resulting surface showed outstanding photoactivity (combined photocatalytic and photothermal properties) for antimicrobial action, conferring reusability and self-sterilizing ability to the masks. Under solar illumination, the temperature of this photoactive antiviral mask (PAM) rapidly increased to >70 °C, generating a high level of free radicals that disrupted the membrane of nanosized (∼100 nm) virus-like particles and made the masks self-cleaning and reusable. This PAM design can provide significant protection against the transmission of viral aerosols in the fight against the COVID-19 pandemic.

The precise control of plasmonic nanostructures and their use for less invasive apoptotic pathway-based therapeutics are important but challenging. Here, we introduce a highly controlled synthetic strategy for plasmonic core-petal nanoparticles (CPNs) with massively branched and plasmonically coupled nanostructures. The formation of CPNs was facilitated by the gold chloride-induced oxidative disassembly and rupture of the polydopamine corona around Au nanoparticles and subsequent growth of Au nanopetals. We show that CPNs can act as multifunctional nanoprobes that induce dual photodynamic and photothermal therapeutic effects without a need for organic photosensitizers, coupled with the generation of reactive oxygen species (ROS), and allow for imaging and analyzing cells. Near-infrared laser-activated CPNs can optically monitor and efficiently kill cancer cells via apoptotic pathway by dual phototherapeutic effects and ROS-mediated oxidative intracellular damage with a relatively mild increase in temperature, low laser power, and short laser exposure time.

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The outbreak of coronavirus disease (COVID-19) has transformed the daily lifestyles of people worldwide. COVID-19 was characterized as a pandemic owing to its global spread, and technologies based on engineered materials that help to reduce the spread of infections have been reported. Nanotechnology present in materials with enhanced physicochemical properties and versatile chemical functionalization offer numerous ways to combat the disease. Facemasks are a reliable preventive measure, although they are not 100% effective against viral infections. Nonwoven materials, which are the key components of masks, act as barriers to the virus through filtration. However, there is a high chance of cross-infection because the used mask lacks virucidal properties and can become an additional source of infection. The combination of antiviral and filtration properties enhances the durability and reliability of masks, thereby reducing the likelihood of cross-infection. In this review, we focus on masks, from the manufacturing stage to practical applications, and their abilities to combat COVID-19. Herein, we discuss the impacts of masks on the environment, while considering safe industrial production in the future. Furthermore, we discuss available options for future research directions that do not negatively impact the environment.

Coronavirus has affected the entire global community owing to its transmission through respiratory droplets. This has led to the mandatory usage of surgical masks for protection against this lethal virus in many countries. However, the currently available disposable surgical masks have limitations in terms of their hydrophobicity and reusability. Here, we report a single-step spray-coating technique for the formation of a superhydrophobic layer of single-walled carbon nanotubes (SWCNTs) on a meltblown polypropylene (PP) surgical mask. The sprayed SWCNTs form a nanospike-like architecture on the PP surface, increasing the static contact angle for water from 113.6°± 3.0°to 156.2°± 1.8°a nd showing superhydrophobicity for various body fluids such as urine, tears, blood, sweat, and saliva. The CNT-coated surgical masks also display an outstanding photothermal response with an increase in their surface temperature to more than 90 °C within 30 s of 1 sun solar illumination, confirming its self-sterilization ability. Owing to the cumulative effect of the superhydrophobicity and photothermal performance of the SWCNTs, the CNT-coated masks show 99.99% higher bactericidal performance toward Escherichia coli than pristine masks. Further, the virucidal ability of the SWCNT-coated mask, tested by using virus-like particles, was found to be almost 99% under solar illumination. As the spray-coating method is easily scalable, the nanotube-coated mask provides cost-effective personal protection against respiratory diseases.

Exosomes-nanosized extracellular vesicles (EVs) naturally secreted from cells-have emerged as promising biomarkers and potential therapeutic vehicles, but methods to manipulate them for engineering purposes remain elusive. Among the technical obstacles are the small size and surface complexity of exosomes and the complex processing steps required, which reduce the biocompatibility of currently available methods. The encapsulation of exosomes with a nanofilm of supramolecular complexes of ferric ions (Fe ) and tannic acid is demonstrated here. The resulting natural polyphenol, ≈10 nm thick, protects exosomes from external aggressors such as UV-C irradiation or heat and is controllably degraded on demand. Furthermore, gold nanoparticles can be covalently attached for single-exosome level visualization. To fully exploit their therapeutic potential, chemotherapeutic drug-loaded EVs are functionalized to achieve the targeted, selective killing of cancer cells preferentially over normal cells. This nanofilm not only preserves the native size and chemical makeup of the intrinsic exosomes, but also confers new capabilities for efficient tumor targeting and pH-controlled release of drugs. Demonstrating a scalable method to produce biocompatible, durable, on-demand degradable, and chemically controllable shields for exosome modification and functionalization, the methods introduced here are expected to bring the potential of exosome-based nanomedicine applications closer to reality.

Artificial nanoreactors that can facilitate catalysis in living systems on-demand with the aid of a remotely operable and biocompatible energy source are needed to leverage the chemical diversity and expediency of advanced chemical synthesis in biology and medicine. Here, we designed and synthesized plasmonically integrated nanoreactors (PINERs) with highly tunable structure and NIR-light-induced synergistic function for efficiently promoting unnatural catalytic reactions inside living cells. We devised a synthetic approach toward PINERs by investigating the crucial role of metal-tannin coordination polymer nanofilmthe pH-induced decomplexation-mediated phase-transition processfor growing arrays of Au-nanospheroid-units, constructing a plasmonic corona around the proximal and reactant-accessible silica-compartmentalized catalytic nanospace. Owing to the extensive plasmonic coupling effect, PINERs show strong and tunable optical absorption in the visible to NIR range, ultrabright plasmonic light scattering, controllable thermoplasmonic effect, and remarkable catalysis; and, upon internalization by living cells, PINERs are highly biocompatible and demonstrate dark-field microscpy-based bioimaging features. Empowered with the synergy between plasmonic and catalytic effects and reactant/product transport, facilitated by the NIR-irradiation, PINERs can perform intracellular catalytic reactions with dramatically accelerated rates and efficiently synthesize chemically activated fluorescence-probes inside living cells.