Precise control over the spatial arrangement of inorganic nanoparticles on a large scale is desirable for the design of functional nanomaterials, sensing, and optical/electronic devices. Although ...great progress has been recently made in controlling the organization of nanoparticles, there still remains a grand challenge to arrange nanoparticles into highly-ordered arrays over multiple length scales. Here, we report the directed arrangement of inorganic nanoparticles into arrayed structures with long-range order, up to tens of microns, by using hexagonally-packed cylindrical patterns of block copolymer nanosheets self-assembled within collapsed emulsion droplets as scaffolds. This technique can be used to generate nanoparticle arrays with various nanoparticle arrangements, including hexagonal honeycomb structures, periodic nanoring structures, and their combinations. This finding provides an effective route to fabricate diverse nanoparticle arrayed structures for the design of functional materials and devices.
Luminescence lifetime imaging plays an important role in distinguishing the luminescence decay rates in time-resolved luminescence imaging. However, traditional imaging instruments used for detecting ...lifetimes within milliseconds would be time-consuming when imaging ultra-long luminescence lifetimes over subseconds. Herein, we present an accessible and simple optical system for detecting lifetimes of persistent luminescence. A smartphone integrated with a UV LED, a dichroic mirror, and a lens was used for recording the persistent luminescence. With only a few seconds of data acquisition, a luminescence lifetime image could be processed from the video by exponential fitting of the gray level of each pixel to the delay time. Since this approach only requires single excitation, no synchronous control is needed, greatly simplifying the apparatus and saving the cost. The apparatus was successfully used for ultra-long luminescence lifetime imaging of mouse tissue dyed with a persistent luminescence molecule. This miniaturized apparatus exhibits huge potentiality in time-resolved luminescence imaging for luminescence study and biological detection.
Graphical abstract
Wound management is a crucial measure for skin wound healing and is significantly important to maintaining the integrity of skins and their functions. Electrical stimulation at the wound site is a ...compelling strategy for skin wound repair. However, there has been an urgent need for wearable and point-of-care electrical stimulation devices that have self-adhesive and mechanical properties comparable to wound tissue. Herein, we develop a bioinspired hybrid patch with self-adhesive and piezoelectric nanogenerator (HPSP) for promoting skin wound healing, which is composed of a mussel-inspired hydrogel matrix and a piezoelectric nanogenerator based on aligned electrospun poly(vinylidene fluoride) nanofibers. The device with optimized modulus and permeability for skin wear can self-adhere to the wound site and locally produce a dynamic voltage caused by motion. We show that the HPSP not only promotes fibroblast proliferation and migration
in vitro
, but also effectively facilitates the collagen deposition, angiogenesis, and re-epithelialization
in vivo
with the increased expressions of crucial growth factors. The HPSP reduces the wound closure time of full-thickness skin defects by about 1/3, greatly accelerating the healing process. This patch can serve as wearable and real-time electrical stimulation devices, potentially useful in clinical applications of skin wound healing.
Worm holes: Cylindrical or wormlike block copolymer micelles with gold nanoparticles encapsulated in a micellar core were fabricated through directed supramolecular assembly. This versatile approach ...allows fine‐tuning of interparticle spacing and micellar morphology by varying the content of the nanoparticles or hydrogen bonding agent in the supramolecular assemblies.
Perovskite solid solution ceramics of (1 − x)BiFeO3–xBaTiO3 (1 − x)BF–xBT, 0.2 ≤ x ≤ 0.45) with high electrical resistivity were prepared by solid‐state reaction method. Actual ferroelectric ...hysteresis loops and temperature dependence of dielectric constant of the ceramics were obtained. Ceramics of 0.7BF–0.3BT with small rhombohedral distortion show highest remnant polarization (Pr = 26.0 μC/cm2) and piezoelectric coefficient (d33 = 134 pC/N). Compositions with pseudo‐cubic symmetry (intermediate phases) show relaxor‐like dielectric anomaly. The values of Pr and d33 decrease with increasing BT content, from 24.8 μC/cm2 and 104 pC/N for 0.65BF–0.35BT to 8.2 μC/cm2 and 5 pC/N for 0.55BF–0.45BT.
A reversible transformation of overall shape and internal structure as well as surface composition of nanostructured block copolymer particles is demonstrated by solvent-adsorption annealing. ...Polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) pupa-like particles with PS and P4VP lamellar domains alternatively stacked can be obtained by self-assembly of the block copolymer under 3D soft confinement. Chloroform, a good solvent for both blocks, is selected to swell and anneal the pupa-like particles suspended in aqueous media. Reversible transformation between pupa-like and onion-like structures of the particles can be readily tuned by simply adjusting the particle/aqueous solution interfacial property. Interestingly, poly(vinyl alcohol) (PVA) concentration in the aqueous media plays a critical role in determining the particle morphology. High level of PVA concentration is favorable for pupa-like morphology, while extremely low concentration of PVA is favorable for the formation of onion-like particles. Moreover, the stimuli-response behavior of the particles can be highly suppressed through selective growth of Au nanoparticles within the P4VP domains. This strategy provides a new concept for the reversible transformation of nanostructured polymer particles, which will find potential applications in the field of sensing, detection, optical devices, drug delivery, and smart materials fabrication.
C-X-C chemokine receptor type 2 (CXCR2) is a key regulator that drives immune suppression and inflammation in tumor microenvironment. CXCR2-targeted therapy has shown promising results in several ...solid tumors. However, the underlying mechanism of CXCR2-mediated cross-talk between gastric cancer cells and macrophages still remains unclear.
The expression of CXCR2 and its ligands in 155 human gastric cancer tissues was analyzed via immunohistochemistry, and the correlations with clinical characteristics were evaluated. A coculture system was established, and functional assays, including ELISA, transwell, cell viability assay, and qPCR, were performed to determine the role of the CXCR2 signaling axis in promoting gastric cancer growth and metastasis. A xenograft gastric cancer model and a lymph node metastasis model were established to study the function of CXCR2
.
CXCR2 expression is associated with the prognosis of patients with gastric cancer (
= 0.002). Of all the CXCR2 ligands, CXCL1 and CXCL5 can significantly promote migration of gastric cancer cells. Macrophages are the major sources of CXCL1 and CXCL5 in the gastric cancer microenvironment, and promote migration of gastric cancer cells through activating a CXCR2/STAT3 feed-forward loop. Gastric cancer cells secrete TNF-α to induce release of CXCL1 and CXCL5 from macrophages. Inhibiting CXCR2 pathway of gastric cancer cells can suppress migration and metastasis of gastric cancer
and
.
Our study suggested a previously uncharacterized mechanism through which gastric cancer cells interact with macrophages to promote tumor growth and metastasis, suggesting that CXCR2 may serve as a promising therapeutic target to treat gastric cancer.
The Moebius topology (twisted, single-sided strip) is intriguing because of its structural elegance and distinct properties. Here we report the generation of block copolymer Moebius strips via a fast ...self-assembly of chiral block copolymer polystyrene-block-poly(D-lactide acid) (PS-b-PDLA) in tetrahydrofuran/water mixed solvents. The Moebius strip is formed by morphological evolution from large compound micelle (LCM) to spindle-like micelle (SLM) and then to toroid with a 180° twist along the ring. Mechanism insight reveals that a subtle balance of crystallization of PDLA and microphase separation between PS and PDLA chains dominates the formation of Moebius strips. An intriguing helix-helix transition occurs during the chiral transfer from microphase to assemblies, which is driven by relaxation of the internal stress within SLM related to orientated stretching of PS chains. Mesoporous chiral channels can be generated within Moebius strips after removal of PDLA, which are interesting in chiral recognition, separation and asymmetric catalysis.
Structural colors provide a promising visualization with high color saturation, iridescent characteristics, and fade resistance. However, pragmatic uses are frequently impeded by complex ...manufacturing processes for sophisticated nanostructures. Here, we report a facile emulsion-templating strategy to produce crescent-shaped microparticles as structural color pigments. The micro-crescents exhibit brilliant colors under directional light originating from total internal reflections and optical interferences in the absence of periodic nanostructures while being transparent under ambient light. The colors are finely tunable by adjusting the size of the micro-crescents, which can be further mixed to enrich the variety. Importantly, the pre-defined convex surface secures high stability of colors and enables structural coloration on target surfaces through direct deposition as inks. We anticipate this class of nanostructure-free structural colorants is pragmatic as invisible inks in particular for anti-counterfeiting patches and color cosmetics with distinctive impressions due to low-cost, scalable manufacturing, unique optical properties, and versatility.
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