Bifunctionalized mesoporous silica-supported gold nanoparticles as oxidase and peroxidase mimics for antibacterial applications are demonstrated. For the first time, these mesoporous silica-supported gold nanoparticles are applied as oxidase and peroxidase mimics. Taking advantage of their prominent enzyme activities, the MSN-AuNPs show excellent antibacterial properties against both Gram-negative and Gram-positive bacteria. Furthermore, MSN-AuNPs also exhibit outstanding performance in biofilm elimination .

Reactive oxygen species (ROS)-induced apoptosis is a promising treatment strategy for malignant neoplasms. However, current systems are highly dependent on oxygen status and/or external stimuli to generate ROS, which greatly limit their therapeutic efficacy particularly in hypoxic tumors. Herein, we develop a biomimetic nanoflower based on self-assembly of nanozymes that can catalyze a cascade of intracellular biochemical reactions to produce ROS in both normoxic and hypoxic conditions without any external stimuli. In our formulation, PtCo nanoparticles are firstly synthesized and used to direct the growth of MnO2. By adjusting the ratio of reactants, highly-ordered MnO2@PtCo nanoflowers with excellent catalytic efficiency are obtained, where PtCo behaves as oxidase mimic and MnO2 functions as catalase mimic. In this way, the well-defined MnO2@PtCo nanoflowers not only can relieve hypoxic condition but also induce cell apoptosis significantly through ROS-mediated mechanism, thereby resulting in remarkable and specific inhibition of tumor growth.

Graphitic carbon nitride (g-C3 N4 ) has been used as photosensitizer to generate reactive oxygen species (ROS) for photodynamic therapy (PDT). However, its therapeutic efficiency was far from satisfactory. One of the major obstacles was the overexpression of glutathione (GSH) in cancer cells, which could diminish the amount of generated ROS before their arrival at the target site. Herein, we report that the integration of Cu(2+) and g-C3 N4 nanosheets (Cu(2+) -g-C3 N4 ) led to enhanced light-triggered ROS generation as well as the depletion of intracellular GSH levels. Consequently, the ROS generated under light irradiation could be consumed less by reduced GSH, and efficiency was improved. Importantly, redox-active species Cu(+) -g-C3 N4 could catalyze the reduction of molecular oxygen to the superoxide anion or hydrogen peroxide to the hydroxyl radical, both of which facilitated the generation of ROS. This synergy of improved ROS generation and GSH depletion could enhance the efficiency of PDT for cancer therapy.

Rapid diagnosis is critical for the treatment and prevention of diseases. An advanced nanomaterial‐based biosensing platform that detects COVID‐19 antibodies within seconds is reported. The biosensing platform is created by 3D nanoprinting of three‐dimensional electrodes, coating the electrodes by nanoflakes of reduced‐graphene‐oxide (rGO), and immobilizing specific viral antigens on the rGO nanoflakes. The electrode is then integrated with a microfluidic device and used in a standard electrochemical cell. When antibodies are introduced on the electrode surface, they selectively bind with the antigens, changing the impedance of the electrical circuit which is detected via impedance spectroscopy. Antibodies to SARS‐CoV‐2 spike S1 protein and its receptor‐binding‐domain (RBD) are detected at a limit‐of‐detection of 2.8 × 10−15 and 16.9 × 10−15 m, respectively, and read by a smartphone‐based user interface. The sensor can be regenerated within a minute by introducing a low‐pH chemistry that elutes the antibodies from the antigens, allowing successive sensing of test samples using the same sensor. Sensing of S1 and RBD antibodies is specific, which cross‐reacts neither with other antibodies such as RBD, S1, and nucleocapsid antibody nor with proteins such as interleukin‐6. The proposed sensing platform could also be useful to detect biomarkers for other infectious agents such as Ebola, HIV, and Zika.

In this work, for the first time, we constructed a novel multi-nanozymes cooperative platform to mimic intracellular antioxidant enzyme-based defense system. V2 O5 nanowire served as a glutathione peroxidase (GPx) mimic while MnO2 nanoparticle was used to mimic superoxide dismutase (SOD) and catalase (CAT). Dopamine was used as a linker to achieve the assembling of the nanomaterials. The obtained V2 O5 @pDA@MnO2 nanocomposite could serve as one multi-nanozyme model to mimic intracellular antioxidant enzyme-based defense procedure in which, for example SOD, CAT, and GPx co-participate. In addition, through assembling with dopamine, the hybrid nanocomposites provided synergistic antioxidative effect. Importantly, both in vitro and in vivo experiments demonstrated that our biocompatible system exhibited excellent intracellular reactive oxygen species (ROS) removal ability to protect cell components against oxidative stress, showing its potential application in inflammation therapy.

Nanoparticulate delivery platforms have shown promising advantages for vaccines in many aspects. However, their application was limited so far by lengthy synthetic protocols, the requirement of specific modification of antigen, and by the low efficiency in inducing antigen‐specific cytotoxic T‐lymphocyte responses. This study demonstrates for the first time the construction of metal‐organic‐framework (MOF) based vaccines by encapsulating ovalbumin (OVA) and attaching the cytosine‐phosphate‐guanine oligodeoxynucleotides (CpG ODNs) in/on zeolitic imidazolate framework‐8 (ZIF‐8) nanoparticles. The pH responsive decomposition feature enables the system to release the protein antigens and CpG ODNs in the same antigen presenting cells more efficiently. More importantly, in addition to the induction of a potent immune memory response, both in vitro and in vivo experiments show that the vaccines can induce strong humoral and cellular immunity. These findings suggest that the MOF‐based vaccine platforms can be used to produce effective vaccines against a range of ailments, which will facilitate the application of MOFs in biomedical areas.

Silver nanoparticles (AgNPs) have been used as a broad-spectrum antimicrobial agent, whose toxicity originates from the localized release of Ag ions. However, the residual AgNPs core could generate potential risk to humans and waste of noble metals. Herein, we infused the cysteine-modified molybdenum disulfide with minimum Ag ions and coated with a layer of cationic polyelectrolyte to construct an efficient and benign antimicrobial depot. The system exhibited much enhanced broad-spectrum antibacterial activity compared with an equivalent amount of silver nitrate, owing to its increasing accessibility of released Ag to the cell walls of microorganisms. More importantly, the antibacterial system could be successfully applied to treat wound infection, while retaining high antibacterial activities, exhibiting negligible biotoxicity and avoiding the waste of Ag.

Manipulation of cell–cell interactions has potential applications in basic research and cell-based therapy. Herein, using a combination of metabolic glycan labelling and bio-orthogonal click reaction, we engineer cell membranes with β-cyclodextrin and subsequently manipulate cell behaviours via photo-responsive host-guest recognition. With this methodology, we demonstrate reversible manipulation of cell assembly and disassembly. The method enables light-controllable reversible assembly of cell–cell adhesion, in contrast with previously reported irreversible effects, in which altered structure could not be reused. We also illustrate the utility of the method by designing a cell-based therapy. Peripheral blood mononuclear cells modified with aptamer are effectively redirected towards target cells, resulting in enhanced cell apoptosis. Our approach allows precise control of reversible cell–cell interactions and we expect that it will promote further developments of cell-based therapy.