Due to the near-field coupling effect, non-close-packed nanoparticle (NP) assemblies with tunable interparticle distance (d) attract great attention and show huge potential applications in various functional devices, e.g., organic nano-floating-gate memory (NFGM) devices. Unfortunately, the fabrication of device-scale non-close-packed 2D NPs material still remains a challenge, limiting its practical applications. Here, a facile yet robust "rapid liquid-liquid interface assembly" strategy is reported to generate a non-close-packed AuNP superlattice monolayer (SM) on a centimeter scale for high-performance pentacene-based NFGM. The d and hence the surface plasmon resonance spectra of SM can be tailored by adjusting the molecular weight of tethered polymers. Precise control over the d value allows the successful fabrication of photosensitive NFGM devices with highly tunable performances from short-term memory to nonvolatile data storage. The best performing nonvolatile memory device shows remarkable 8-level (3-bit) storage and a memory ratio over 10 even after 10 years compared with traditional devices with a AuNP amorphous monolayer. This work provides a new opportunity to obtain large area 2D NPs materials with non-close-packed structure, which is significantly meaningful to microelectronic, photovoltaics devices, and biochemical sensors.
Wound infection can cause a delay in wound healing or even wound deterioration, threatening patients' lives. The excessive accumulation of reactive oxygen species (ROS) in infected wounds activates a strong inflammatory response to delay wound healing. Therefore, it is highly desired to develop hydrogels with inherent antimicrobial activity and antioxidant capability for infected wound healing. Herein, a dopamine-substituted multidomain peptide (DAP) with inherent antimicrobial activity, strong skin adhesion, and ROS scavenging has been developed. DAP can form bilayer β-sheets with dopamine residues on the surface of nanofibers. The enhanced rheological properties of DAP-based hydrogel can be achieved not only through UV irradiation but also by incorporation of multivalent ions (e.g., PO 4 3− ). Furthermore, the DAP hydrogel shows a broad spectrum of antimicrobial activity due to the high positive charges of lysine residues and the βsheet formation. When applied to full-thickness dermal wounds in mice, the DAP hydrogel results in a significantly shortened inflammatory stage of the healing process because of its remarkable antimicrobial activity and antioxidant capability. Accelerated wound closure with thick granulation tissue, uniform collagen arrangement, and dense vascularization can be achieved. This work suggests that the DAP hydrogel can serve as antimicrobial coating and ROS-scavenging wound dressing for bacterial-infected wound treatment.
Solar-driven
water
evaporation is of great importance for freshwater production via solar
distillation and has attracted growing attention recently by the development
of heat localization strategies. Yet, when polluted water is used
as the source water, solar-driven water evaporation might further
deteriorate the pollution. In this study, we report the facile preparation
of multifunctional Ag3PO4-reduced graphene oxide
(Ag3PO4-rGO) nanocomposite-coated textiles for
clean water production by solar-driven water evaporation, photocatalysis,
and disinfection. The multifunctional textiles are obtained through
coating Ag3PO4-rGO nanocomposites onto cotton
textile substrates. The resulting textile can float on the water surface,
absorb solar light, and convert it into heat, enhancing the water
surface temperature and promoting water evaporation. We show that
with Ag3PO4-rGO nanocomposite-coated textiles
on the water surface, a high water evaporation rate of 1.31 kg/(m2 h) can be reached under solar light irradiation. Furthermore,
the textiles can simultaneously decompose organic dyes and disinfect
pathogenic microbes in water, purifying the raw water during solar-driven
water evaporation. Such an all-in-one multifunctional textile provides
a facile yet sustainable strategy for freshwater production.
The presence of surfaces influences the kinetics of amyloid-β (Aβ) peptide fibrillation. Although it has been generally recognized that the fibrillation process can be assisted or accelerated by surface chemistry, the impact of surface topography, i.e., roughness, on peptide fibrillation is relatively little understood. Here we study the role of surface roughness on surface-mediated fibrillation using polymer coatings of varying roughness as well as polymer microparticles. Using single-molecule tracking, atomic force microscopy, and the thioflavin T fluorescence technique, we show that a rough surface decelerates the two-dimensional (2D) diffusion of peptides and retards the surface-mediated fibrillation. A higher degree of roughness that presents an obstacle to peptide diffusion is found to inhibit the fibrillation process.
Antibiotics’
abuse in bacteria-infected wounds has threatened
patients’ lives and burdened medical systems. Hence, antibiotic-free
hydrogel-based biomaterials, which exhibit biostability, on-demand
release of antibacterial agents, and long-lasting antimicrobial activity,
are highly desired for the treatment of chronic bacteria-infected
wounds. Herein, we developed a hyaluronic acid (HA)-based
composite hydrogel, with an antimicrobial peptide [AMP, KK(SLKL)3KK] as a cross-linking agent through Schiff’s
base formation, which exhibited an acidity-triggered release of AMP (pathological environment in bacteria-infected wounds,
pH ∼ 5.5–5.6). During the self-assembly process, AMP adopted an antiparallel β-sheet secondary structure
due to the alternate arrangement of hydrophobic and hydrophilic residues
of amino acids. Owing to Schiff’s base formation between the
primary amines derived from lysine residues and the aldehydes in oxidized HA, the AMP–HA composite hydrogel exhibited
injectability, high biostability, and enhanced mechanical strength.
Importantly, both AMP and the AMP–HA composite showed excellent broad-spectrum antibacterial activity in vitro and in vivo. Specifically, the AMP–HA composite hydrogel exhibited on-demand full
thickness wound healing in an infected mice model. Therefore, this
work provides an efficient strategy to fabricate antibiotic-free hydrogel-based
biomaterials for the management of chronic bacteria-infected wounds.
Generally, size, uniformity, shape, and surface chemistry of biodegradable polymer particles will significantly affect the drug-release behavior in vitro and in vivo. In this study, uniform poly(d,l-lactic-co-glycolide) (PLGA) and PLGA-b-poly(ethylene glycol) (PLGA-b-PEG) microparticles with tunable surface textures were generated by combining the interfacial instabilities of emulsion droplet and polymer-blending strategy. Monodisperse emulsion droplets containing polymers were generated through the microfluidic flow-focusing technique. The removal of organic solvent from the droplets triggered the interfacial instabilities (spontaneous increase in interfacial area), leading to the formation of uniform polymer particles with textured surfaces. With the introduction of homopolymer PLGA to PLGA-b-PEG, the hydrophobicity of the polymer system was tailored, and a qualitatively different interfacial behavior of the emulsion droplets during solvent removal was observed. Uniform polymer particles with tunable surface roughness were thus generated by changing the ratio of PLGA-b-PEG in the polymer blends. More interestingly, surface textures of the particles determined the drug-loading efficiency and release kinetics of the encapsulated hydrophobic paclitaxel, which followed a diffusion-directed drug-release pattern. The polymer particles with different surface textures demonstrated good cell viability and biocompatibility, indicating the promising role of the particles in the fields of drug or gene delivery for tumor therapy, vaccines, biodiagnostics, and bioimaging.
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