Triboelectric nanogenerators (TENGs) have emerged as promising devices for generating self-powered therapeutic electrical stimulation over multiple aspects of wound healing. However, the challenge of achieving full 100% contact in conventional TENGs presents a substantial hurdle in the quest for higher current output, which is crucial for further improving healing efficacy. Here, a novel multifunctional wound healing system is presented by integrating the aqueous-aqueous triboelectric nanogenerators (A-A TENGs) with a functionalized conductive hydrogel, aimed at advancing infected wound therapy. The A-A TENGs are founded on a principle of 100% contact interface and efficient post-contact separation of the immiscible interface within the aqueous two-phase system (ATPS), enhancing charge transfer and subsequently increasing current performance. Leveraging this intensified current output, this system demonstrates efficient therapeutic efficacies over infected wounds both in vitro and in vivo, including stimulating fibroblast migration and proliferation, boosting angiogenesis, enhancing collagen deposition, eradicating bacteria, and reducing inflammatory cells. Moreover, the conductive hydrogel ensures the uniformity and integrity of the electric field covering the wound site, and exhibits multiple synergistic therapeutic effects. With the capability to realize accelerated wound healing, the developed "A-A TENGs empowered multifunctional wound healing system" presenting an excellent prospect in clinical wound therapy.
Man-made DNA materials hold the potential to modulate specific immune pathways toward immunoactivating or immunosuppressive cascades. DNA-based biomaterials introduce DNA into the extracellular environment during implantation or delivery, and subsequently intracellularly upon phagocytosis or degradation of the material. Therefore, the immunogenic functionality of biological and synthetic extracellular DNA should be considered to achieve desired immune responses. In vivo, extracellular DNA from both endogenous and exogenous sources holds immunoactivating functions which can be traced back to the molecular features of DNA, such as sequence and length. Extracellular DNA is recognized as damage-associated molecular patterns (DAMPs), or pathogen-associated molecular patterns (PAMPs), by immune cell receptors, activating either proinflammatory signaling pathways or immunosuppressive cell functions. Although extracellular DNA promotes protective immune responses during early inflammation such as bacterial killing, recent advances demonstrate that unresolved and elevated DNA concentrations may contribute to the pathogenesis of autoimmune diseases, cancer, and fibrosis. Therefore, addressing the immunogenicity of DNA enables immune responses to be engineered by optimizing their activating and suppressive performance per application. To this end, emerging biology relevant to the generation of extracellular DNA, DNA sensors, and its role concerning existing and future synthetic DNA biomaterials are reviewed.
Neutrophil extracellular traps (NETs) are decondensed chromatin networks released by neutrophils that can trap and kill pathogens but can also paradoxically promote biofilms. The mechanism of NET functions remains ambiguous, at least in part, due to their complex and variable compositions. To unravel the antimicrobial performance of NETs, a minimalistic NET-like synthetic structure, termed "microwebs," is produced by the sonochemical complexation of DNA and histone. The prepared microwebs have structural similarity to NETs at the nanometer to micrometer dimensions but with well-defined molecular compositions. Microwebs prepared with different DNA to histone ratios show that microwebs trap pathogenic Escherichia coli in a manner similar to NETs when the zeta potential of the microwebs is positive. The DNA nanofiber networks and the bactericidal histone constituting the microwebs inhibit the growth of E. coli. Moreover, microwebs work synergistically with colistin sulfate, a common and a last-resort antibiotic, by targeting the cell envelope of pathogenic bacteria. The synthesis of microwebs enables mechanistic studies not possible with NETs, and it opens new possibilities for constructing biomimetic bacterial microenvironments to better understand and predict physiological pathogen responses.
Abstract Living cells have evolved over billions of years to develop structural and functional complexity with numerous intracellular compartments that are formed due to liquid–liquid phase separation (LLPS). Discovery of the amazing and vital roles of cells in life has sparked tremendous efforts to investigate and replicate the intracellular LLPS. Among them, all‐aqueous emulsions are a minimalistic liquid model that recapitulates the structural and functional features of membraneless organelles and protocells. Here, an emerging all‐aqueous microfluidic technology derived from micrometer‐scaled manipulation of LLPS is presented; the technology enables the state‐of‐art design of advanced biomaterials with exquisite structural proficiency and diversified biological functions. Moreover, a variety of emerging biomedical applications, including encapsulation and delivery of bioactive gradients, fabrication of artificial membraneless organelles, as well as printing and assembly of predesigned cell patterns and living tissues, are inspired by their cellular counterparts. Finally, the challenges and perspectives for further advancing the cell‐inspired all‐aqueous microfluidics toward a more powerful and versatile platform are discussed, particularly regarding new opportunities in multidisciplinary fundamental research and biomedical applications.
In this study, Janus droplets are fabricated by inducing phase separation of single‐phase droplets made up of an aqueous two‐phase system (ATPS). The resultant Janus droplets are highly monodisperse in structures and internal morphologies. Due to the affinity partitioning properties of ATPS, encapsulated ingredients can automatically partition into different compartments of the resultant Janus droplets. The use of biocompatible and cytocompatible ATPS also enables the encapsulation of enzymes and cells in the resultant droplets with their activity preserved at a relatively high level. image
We develop an approach to fabricate monodisperse water-in-water-in-water (w/w/w) double emulsion in microfluidic devices. A jet of aqueous solution containing two incompatible solutes, dextran and polyethylene glycol (PEG), is periodically perturbed into water-in-water (w/w) droplets. By extracting water out of the w/w droplet, the solute concentrations in the droplet phase increase; when the concentrations exceed the miscibility limit, the droplet phase separates into two immiscible phases. Consequently, PEG-rich droplets are formed within the single emulsion templates. These PEG-rich droplets subsequently coalesce with each other, resulting in transiently stable w/w/w double emulsions with a high degree of size uniformity. These double emulsions are free of organic solvents and thus are ideal for use as droplet-vessels in protein purification, as microreactors for biochemical reactions, and as templates for fabrication of biomaterials.
Networks of natural protein nanofibrils, such as cytoskeletal filaments, control the shape and the division of cells, yet mimicking this functionality in a synthetic setting has proved challenging. Here, we demonstrate that artificial networks of protein nanofibrils can induce controlled deformation and division of all-aqueous emulsion droplets with budding-like morphologies. We show that this process is driven by the difference in the immersional wetting energy of the nanofibril network, and that both the size and the number of the daughter droplets formed during division can be controlled by modulating the fibril concentration and the chemical properties of the fibril network. Our results demonstrate a route for achieving biomimetic division with synthetic self-assembling fibrils and offer an engineered approach to regulate the morphology of protein gels.
Intrinsically disordered peptides drive dynamic liquid–liquid phase separation (LLPS) in membraneless organelles and encode cellular functions in response to environmental stimuli. Engineering design on phase-separating peptides (PSPs) holds great promise for bioimaging, vaccine delivery, and disease theranostics. However, recombinant PSPs are devoid of robust luminogen or suitable cell permeability required for intracellular applications. Here, we synthesize a peptide-based RNA sensor by covalently connecting tetraphenylethylene (TPE), an aggregation-induced emission luminogen (AIEgens), to tandem peptide repeats of (RRASL)n (n = 1, 2, 3). Interestingly, the conjugation of TPE luminogen promotes liquid–liquid phase separation of the peptide repeats, and the minimum coacervation concentration (MCC) of TPE-(RRASL)n is decreased by an order of magnitude, compared to that of the untagged, TPE-free counterparts. Moreover, the luminescence of TPE-(RRASL)n is enhanced by up to 700-fold with increasing RNA concentration, which is attributed to the constricted rotation of the TPE moiety as a result of peptide/RNA coacervates within the droplet phase. Besides, at concentrations above MCC, TPE-(RRASL)n can efficiently penetrate through human gallbladder carcinoma cells (SGC-996), translocate into the cell nucleus, and colocalize with intracellular RNA. These observations suggest that AIEgen-conjugated PSPs can be used as droplet-based biosensors for intracellular RNA imaging through a regime of coacervation-induced emission.
Photoanode‐driven photoelectrocatalytic (PEC) reduction of CO 2 is an ideal way for solving problems such as the greenhouse effect and environmental crisis. In this study, a one‐step hydrothermal method is successfully used for the preparation of BiVO 4 films doped with different mass fractions of Mo. In the results, it is shown that when Mo is doped at 1.5 wt%, photocurrent densities of up to 4.11 mA cm −2 are obtained, 3.36 times greater than those of undoped BiVO 4 , and there is a marked cathodic shifting of water oxidation reaction initiation potential. Subsequently, coupling it with the BiOBr nanosheet cathode, the generated CH 3 OH rate reaches 45.67 μmol L −1 h −1 cm −2 at a low applied voltage of 1.2 V RHE , with a Faraday efficiency of 60.68% for PEC CO 2 reduction. This work is important for Bi‐based thin‐film self‐assembly coupled with PEC CO 2 systems.
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