Aggregation-induced emission-active micelles: synthesis, characterization, and applications.

Aggregation-induced emission (AIE)-active micelles are a type of fluorescent functional materials that exhibit enhanced emissions in the aggregated surfactant state. They have received significant interest due to their excellent fluorescence efficiency in the aggregated state, remarkable processability, and solubility. AIE-active micelles can be designed through the self-assembly of amphipathic AIE luminogens (AIEgens) and the encapsulation of non-emissive amphipathic molecules in AIEgens. Currently, a wide range of AIE-active micelles have been constructed, with a significant increase in research interest in this area. A series of advanced techniques has been used to characterize AIE-active micelles, such as cryogenic-electron microscopy (Cryo-EM) and confocal laser scanning microscopy (CLSM). This review provides an overview of the synthesis, characterization, and applications of AIE-active micelles, especially their applications in cell and in vivo imaging, biological and organic compound sensors, anticancer drugs, gene delivery, chemotherapy, photodynamic therapy, and photocatalytic reactions, with a focus on the most recent developments. Based on the synergistic effect of micelles and AIE, it is anticipated that this review will guide the development of innovative and fascinating AIE-active micelle materials with exciting architectures and functions in the future.

Liver-Targeted Near-Infrared Fluorescence/Photoacoustic Dual-Modal Probe for Real-Time Imaging of In Situ Hepatic Inflammation.

Early diagnosis of hepatic inflammation is the key to timely treatment and avoid the worsening of liver inflammation. Near-infrared fluorescence (NIRF) probes have high sensitivity but low spatial resolution in lesion imaging, while photoacoustic (PA) imaging has good spatial location information. Therefore, the development of a NIRF/PA dual-modal probe integrated with high sensitivity and spatial location feedback can achieve an accurate early diagnosis of hepatic inflammation. Here, we report an activatable NIRF/PA dual-modal probe (hCy-Tf-CA) for the detection of the superoxide anion (O2·-) in early hepatic inflammation. hCy-Tf-CA showed high selectivity and sensitivity for detecting O2·- fluctuation in vitro. More importantly, by introducing hepatocyte-targeting cholic acid (CA), the probe successfully achieved accurate in situ imaging of acute inflammatory liver injury (AILI) and autoimmune hepatitis (AIH) in vivo. The introduced CA not only promotes the hepatic targeting accumulation of probes but also improves the performance of low background dual-modal imaging in vivo. Therefore, hCy-Tf-CA provides an effective strategy for significantly improving in situ imaging performance and holds great potential for early, sensitive, and accurate diagnosis of hepatic inflammation.

Machine Learning Color Feature Analysis of a High Throughput Nanoparticle Conjugate Sensing Assay.

Plasmonic nanoparticles are finding applications within the single molecule sensing field in a "dimer" format, where interaction of the target with hairpin DNA causes a decrease in the interparticle distance, leading to a localized surface plasmon resonance shift. While this shift may be detected using spectroscopy, achieving statistical relevance requires the measurement of thousands of nanoparticle dimers and the timescales required for spectroscopic analysis are incompatible with point-of-care devices. However, using dark-field imaging of the dimer structures, simultaneous digital analysis of the plasmonic resonance shift after target interaction of thousands of dimer structures may be achieved in minutes. The main challenge of this digital analysis on the single-molecule scale was the occurrence of false signals caused by non-specifically bound clusters of nanoparticles. This effect may be reduced by digitally separating dimers from other nanoconjugate types. Variation in image intensity was observed to have a discernible impact on the color analysis of the nanoconjugate constructs and thus the accuracy of the digital separation. Color spaces wherein intensity may be uncoupled from the color information (hue, saturation, and value (HSV) and luminance, a* vector, and b* vector (LAB) were contrasted to a color space which cannot uncouple intensity (RGB) to train a classifier algorithm. Each classifier algorithm was validated to determine which color space produced the most accurate digital separation of the nanoconjugate types. The LAB-based learning classifier demonstrated the highest accuracy for digitally separating nanoparticles. Using this classifier, nanoparticle conjugates were monitored for their plasmonic color shift after interaction with a synthetic RNA target, resulting in a platform with a highly accurate yes/no response with a true positive rate of 88% and a true negative rate of 100%. The sensor response of tested single stranded RNA (ssRNA) samples was well above control responses for target concentrations in the range of 10 aM-1 pM.

Insecticidal potential of a Consolida ajacis extract and its major compound (ethyl linoleate) against the diamondback moth, Plutella xylostella.

The diamondback moth (Plutella xylostella) is one of the most destructive lepidopteran pests of cruciferous vegetables. However, DBM has developed resistance to current chemical and biological insecticides used for its control, indicating the necessity for finding new insecticides against it. Bio-insecticides derived from plant extracts are eco-friendly alternatives to synthetic pesticides. The aims of this study were to evaluate the insecticidal activity of Consolida ajacis seed extracts against DBM, the underlying mechanism of the control effect of promising extracts, and the identification of the main insecticidal compounds of these extracts. The results showed that ethyl acetate extract of C. ajacis seed exhibited strong contact toxicity (LC50: 5.05 mg/mL), ingestion toxicity, antifeedant, and oviposition deterrent activities against DBM, among the extracts evaluated. At 72 h, glutathiase, acetylcholinesterase, carboxylesterase, peroxidase, and superoxide dismutase activities were inhibited, but catalase activity was activated. The main compound identified from the extract was ethyl linoleate, which had the most significant insecticidal activity on the diamondback moths. This study's findings provide a better understanding of the insecticidal activity of ethyl acetate extract obtained from C. ajacis and its main component (ethyl linoleate). This will help in the development of new insecticides to control DBM.

Statistical predictions on the encapsulation of single molecule binding pairs into sized-dispersed nanocontainers.

Single molecule experiments have recently attracted enormous interest. Many of these studies involve the encapsulation of a single molecule into nanoscale containers (such as vesicles, droplets and nanowells). In such cases, the single molecule encapsulation efficiency is a key parameter to consider in order to get a statistically significant quantitative information. It has been shown that such encapsulation typically follows a Poisson distribution and such theory of encapsulation has only been applied to the encapsulation of single molecules into perfectly sized monodispersed containers. However, experimentally nanocontainers are usually characterized by a size distribution, and often just a single binding pair (rather than a single molecule) is required to be encapsulated. Here the use of Poisson distribution is extended to predict the encapsulation efficiency of two different molecules in an association equilibrium. The Poisson distribution is coupled with a log-normal distribution in order to consider the effect of the container size distribution, and the effect of adsorption to the container is also considered. This theory will allow experimentalists to determine what single molecule encapsulation efficiency can be expected as a function of the experimental conditions. Two case studies, based on experimental data, are given to support the theoretical predictions.

Nanoparticle-based single molecule fluorescent probes.

Single molecule fluorescent probes have attracted considerable attention due to their ultimate sensitivity, fast response, low sample consumption, and high signal-to-noise ratio. Nanoparticles with outstanding optical properties make them perfect candidates for probes in the application of single molecule detection. In this review, we focus on various kinds of nanoparticles acting as single molecule fluorescent probes, including quantum dots, upconverting fluorescent nanoparticles, carbon dots, single-wall carbon nanotubes, fluorescent nanodiamonds, polymeric nanoparticles, nanoclusters, and metallic nanoparticles. Optical properties of various nanoparticles and their recent application in single molecule fluorescent probes are explored. How nanoparticles boost the sensitivity of detection is emphasized in combination with different sensing strategies. Future trends of nanoparticles in single molecule detection are also discussed. We hope that this review can provide practical guidance for researchers who work on nanoparticle-based single molecule fluorescent probes.

Genome-wide identification and characterization of WOX genes in Cucumis sativus.

WUSCHEL-related homeobox (WOX) proteins are plant-specific transcription factors that are profoundly involved in regulation of plant development and stress responses. In this study, we totally identified 11 WOX transcription factor family members in cucumber (Cucumis sativus, CsWOX) genome and classified them into three clades with nine subclades based on phylogenetic analysis results. Alignment of amino acid sequences revealed that all WOX members in cucumber contained the typical homeodomain, which consists of 60-66 amino acids and is folded into a helix-turn-helix structure. Gene duplication event analysis indicated that CsWOX1a and CsWOX1b were a segment duplication pair, which might affect the number of WOX members in cucumber genome. The expression profiles of CsWOX genes in different tissues demonstrated that the members sorted into the ancient clade (CsWOX13a and CsWOX13b) were constitutively expressed at higher levels in comparison to the others. Cis-element analysis in promoter regions suggested that the expression of CsWOX genes was associated with phytohormone pathways and stress responses, which was further supported by RNA-seq data. Taken together, our results provide new insights into the evolution of cucumber WOX genes and improve our understanding about the biological functions of the CsWOX gene family.

Genome-wide analysis of the WRKY gene family in the cucumber genome and transcriptome-wide identification of WRKY transcription factors that respond to biotic and abiotic stresses.

BACKGROUND: Cucumber (Cucumis sativus L.) is an economically important vegetable crop species. However, it is susceptible to various abiotic and biotic stresses. WRKY transcription factors play important roles in plant growth and development, particularly in the plant response to biotic and abiotic stresses. However, little is known about the expression pattern of WRKY genes under different stresses in cucumber. RESULTS: In the present study, an analysis of the new assembly of the cucumber genome (v3.0) allowed the identification of 61 cucumber WRKY genes. Phylogenetic and synteny analyses were performed using related species to investigate the evolution of the cucumber WRKY genes. The 61 CsWRKYs were classified into three main groups, within which the gene structure and motif compositions were conserved. Tissue expression profiles of the WRKY genes demonstrated that 24 CsWRKY genes showed constitutive expression (FPKM > 1 in all samples), and some WRKY genes showed organ-specific expression, suggesting that these WRKYs might be important for plant growth and organ development in cucumber. Importantly, analysis of the CsWRKY gene expression patterns revealed that five CsWRKY genes strongly responded to both salt and heat stresses, 12 genes were observed to be expressed in response to infection from downy mildew and powdery mildew, and three CsWRKY genes simultaneously responded to all treatments analysed. Some CsWRKY genes were observed to be induced/repressed at different times after abiotic or biotic stress treatment, demonstrating that cucumber WRKY genes might play different roles during different stress responses and that their expression patterns vary in response to stresses. CONCLUSIONS: Sixty-one WRKY genes were identified in cucumber, and insight into their classification, evolution, and expression patterns was gained in this study. Responses to different abiotic and biotic stresses in cucumber were also investigated. Our results provide a better understanding of the function of CsWRKY genes in improving abiotic and biotic stress resistance in cucumber.

Possible Way to Study Cononsolvency in Confinement: A Lattice Density Functional Theory Approach.

Polymer lattice density functional theory (PLDFT) is used to investigate the cononsolvency (CNS) phenomena related to polymer adsorption in a slit pore. Specifically, the two simplest types of CNS are examined: CNS1 with solvent-cosolvent binding as the dominant factor and CNS2 with polymer-cosolvent binding as the dominant factor. The simplified models for CNS1/CNS2 well capture the symmetrical/asymmetrical reentrant swelling transition of polymers positively/negatively adsorbed on the solid surface as confirmed by the calculation of PLDFT. To more deeply understand the mechanism of CNS in polymer adsorption, the essential difference and connection between the two types of CNS are analyzed by PLDFT via the quantities as the surface/middle swelling ratio defined for the aggregated layer of polymers in the slit. Further investigation of the effects of binding strength on the collapsing state of the polymer membrane shows the existence of the critical binding energy to trigger drastic collapse through the cosolvent for CNS1 or CNS2. The effects from polymer concentration on two types of CNS are also discussed, showing two important results for CNS2 in agreement with reported experiments. For application, this work indicated the possibility of employing CNS (CNS1) in adsorbed polymers for a tunable surface, as an alternative to polymer brushes.

A novel CuZnInS quantum dot-based ECL sensing system for lysophosphatidic acid detection.

In this paper, a novel electrochemiluminescence (ECL) sensor for lysophosphatidic acid (LPA) detection was developed. LPA consists of a phosphate "head" group, a "linker" region illustrated by glycerol, and a fatty acyl chain as a lipophilic "tail". The water-soluble quaternary CuInZnS quantum dots (QDs) were modified with agmatine (AGM) molecules as an ECL luminophore. On the one hand, the guanidine groups on the QDs can capture the hydrophilic head of LPA with high selectivity. On the other hand, the electrochemically reduced graphene nanosheets (GNs) modified on the glassy carbon electrode (GCE) surface can bind the LPA lipophilic tail. As a result, the LPA-AGM-CuInZnS QDs were captured on the GNs/GCE. The ECL intensity of the system was enhanced with the increased concentration of LPA. As far as we know, it was the first report about LPA detection based on the ECL nanosensing system. The linear relationship range of LPA sensing is from 2 to 75 µmol L-1. The practicability of this ECL sensing platform had shown satisfactory results in human serum samples.

A novel detection method of human serum albumin based on CuInZnS quantum dots-Co2+ sensing system.

We developed a novel "turn off-on" sensor for human serum albumin (HSA) detection based on CuInZnS quantum dots (CIZS QDs). The photoluminescence (PL) of QDs can be "turned off" by Co(II) first. Because of the strong binding ability of HSA with Co2+, Co2+ can be removed from CIZS QDs with the addition of HSA. As a result, the PL of CIZS QDs probe can be "turned on" with an increased concentration of HSA over a wide range. The analyte HSA concentration had a proportional linear relationship with the recovered PL intensity of CIZS QDs. The detection limit for HSA was 4.5 × 10-8 mol L-1. The results indicated that the CIZS QDs- Co2+-BSA sensing system possessed higher sensitivity and better practicability for HSA detection.

N-Doped graphene quantum dot@mesoporous silica nanoparticles modified with hyaluronic acid for fluorescent imaging of tumor cells and drug delivery.

The authors describe new bifunctional mesoporous silica nanoparticles (NPs) for specific targeting of tumor cells and for intracellular delivery of the cancer drug doxorubicin (DOX). Mesoporous silica nanoparticles (MSNPs) were coated with blue fluorescent N-graphene quantum dots, loaded with the drug DOX, and finally coated with hyaluronic acid (HA). Cellular uptake of the NPs with an architecture of the type HA-DOX-GQD@MSNPs enabled imaging of human cervical carcinoma (HeLa) cells via fluorescence microscopy. The cytotoxicity of the nanoparticles on HeLa cells was also assessed. The results suggest that the NPs are higher cytotoxicity effect and exert in living cell imaging ability. Compared to the majority of other drug nanocarrier systems, the one described here enables simultaneous DOX release and fluorescent monitoring. Graphical abstract Schematic of the bifunctional mesoporous silica nanoparticles were obtained via the Stöber method, along with the doxorubicin loaded and the hyaluronic acid capped. The sensor shows good specificity and significant cytotoxicity effect on Hela cells. (TEOS: tetraethyl orthosilicate; GQDs: graphene quantum dots; DOX: doxorubicin; HA: Hyaluronic acid).

Modeling swelling behavior of thermoresponsive polymer brush with lattice density functional theory.

A key problem in designing thermoresponsive polymer brushes on a solid surface is to find a relation between the targeted thermoresponsive properties and controllable conditions. Usually, a temperature-thickness curve showing the heating-induced swelling behavior of polymer brushes is chosen as the relation by either experimental or theoretical investigation. In this work, a lattice density functional theory (LDFT) developed previously is employed to investigate the temperature-thickness curves for five different types of polymer brushes, where the density profiles of polymer brushes calculated by LDFT are compared directly with simulation. It is found that the thermoresponsive behavior of a polymer brush can be characterized by the bulk phase behaviors of its corresponding polymer solution, including UCST, LCST, both UCST and LCST, closed LOOP and hourglass-shaped, which implies that the bulk phase diagram of polymer solutions can help us to find an appropriate polymer brush for a targeted thermoresponsive behavior. As an example, we show that the swelling behavior of a thermoresponsive polymer brush found in the experiment could be predicted by our LDFT results with the bulk phase diagram of real polymer solution only.

Site-Specific Cascade-Activatable Fluorogenic Nanomicelles Enable Precision and Accuracy Imaging of Pulmonary Metastatic Tumor.

The precise localization of metastatic tumors with subtle growth is crucial for timely intervention and improvement of tumor prognosis but remains a paramount challenging. To date, site-specific activation of fluorogenic probes for single-stimulus-based diagnosis typically targets an occult molecular event in a complex biosystem with limited specificity. Herein, we propose a highly specific site-specific cascade-activated strategy to enhance detection accuracy, aiming to achieve the accurate detection of breast cancer (BC) lung metastasis in a cascade manner. Specifically, cascade-activatable NIR fluorogenic nanomicelles HPNs were constructed using ultra-pH-sensitive (UPS) block copolymers as carriers and nitroreductase (NTR)-activated fluorogenic reporters. HPNs exhibit programmable cascade response characteristics by first instantaneous dissociating under in situ tumor acidity, facilitating deep tumor penetration followed by selective fluorescence activation through NTR-mediated enzymatic reaction resulting in high fluorescence ON/OFF contrast. Notably, this unique feature of HPNs enables high-precision diagnosis of orthotopic BC as well as its lung metastases with a remarkable signal-to-background ratio (SBR). This proposed site-specific cascade activation strategy will offer opportunities for a specific diagnosis with high signal fidelity of various insidious metastatic lesions in situ across different diseases.

Diagnostic value of tuberculosis-specific antigens ESAT-6 and CFP10 in lymph node tuberculosis.

Objective: To assess the diagnostic value of immunohistochemical (IHC) staining for detecting the tuberculosis-secreted antigens ESAT-6 and CFP10 in lymph node tuberculosis. Methods: Archived, paraffin-embedded lymph node specimens from 72 patients diagnosed with lymph node tuberculosis and 68 patients with lymphoma were retrospectively collected from the Department of Pathology at the Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan Province, China between January 2016 and March 2023. These specimens were subjected to acid-fast and immunohistochemical staining to compare the effectiveness of these methods, with their sensitivity and specificity evaluated against a comprehensive reference standard. Results: Acid-fast staining demonstrated a sensitivity of 12.3% and a specificity of 100%. IHC staining for ESAT-6 showed a sensitivity of 87.5% and a specificity of 85.3%, whereas IHC staining for CFP10 exhibited a sensitivity of 75.0% and a specificity of 89.7%. Conclusion: The study indicates that IHC detection of ESAT-6 and CFP10 in paraffin-embedded lymph node tuberculosis tissues has a markedly higher sensitivity compared to acid-fast staining. Thus, IHC staining may serve as a supplementary diagnostic tool for the pathological evaluation of lymph node tuberculosis.

Ultrastiff metamaterials generated through a multilayer strategy and topology optimization.

Metamaterials composed of different geometrical primitives have different properties. Corresponding to the fundamental geometrical forms of line, plane, and surface, beam-, plate-, and shell-based lattice metamaterials enjoy many advantages in many aspects, respectively. To fully exploit the advantages of each structural archetype, we propose a multilayer strategy and topology optimization technique to design lattice metamaterial in this study. Under the frame of the multilayer strategy, the design space is enlarged and diversified, and the design freedom is increased. Topology optimization is applied to explore better designs in the larger and diverse design space. Beam-plate-shell-combined metamaterials automatically emerge from the optimization to achieve ultrahigh stiffness. Benefiting from high stiffness, energy absorption performances of optimized results also demonstrate substantial improvements under large geometrical deformation. The multilayer strategy and topology optimization can also bring a series of tunable dimensions for lattice design, which helps achieve desired mechanical properties, such as isotropic elasticity and functionally grading material property, and superior performances in acoustic tuning, electrostatic shielding, and fluid field tuning. We envision that a broad array of synthetic and composite metamaterials with unprecedented performance can be designed with the multilayer strategy and topology optimization.

Lock/unlock mechanism of solvent-responsive binary polymer brushes: density functional theory approach.

A density functional theory (DFT) approach based on a weighted density approximation has been employed to study the perpendicular microphase separation of symmetric binary polymer brushes with weak incompatibility in explicit solvents with different selectivities. Characterized by the relation between the grand potential and vertical structures (including nonlayered and layered structures), a dry binary brush can be categorized as W-type or U-type according to whether the characteristic relation contains a structure that undergoes spontaneous symmetry breaking. A W-type brush can memorize the selectivity of the induced solvent in one of its two layered structures after the removal of solvent, which can be seen as a kind of lock state with the nonselective solvent used as its key to unlock. A U-type brush is lockless but can adapt to the environment without the nonselective solvent's triggering. Also, the boundary described in chain-length-incompatibility space is investigated by the DFT approach, which also verifies that the spontaneous symmetry breaking of the W-type brush originates from the molecular contributions to asymmetry, such as the enthalpic contribution of incompatibility and the entropic contribution of chain connectivity.

Electrochemical fluorescence switching of enhanced green fluorescent protein.

Switchable fluorescent proteins, for which fluorescence can be switched ON and OFF, are widely used for molecule tracking and super resolution imaging. However, the robust use of the switchable fluorescent proteins is still limited as either the switching is not repeatable, or such switching requires irradiation with coupled lasers of different wavelengths. Herein, we report an electrochemical approach to reversible fluorescence switching for enhanced green fluorescent proteins (EGFP) on indium tin oxide coated glass. Our results demonstrate that negative and positive electrochemical potentials can efficiently switch the fluorescent proteins between the dim (OFF) and bright (ON) states at the single molecule level. The electrochemical fluorescence switching is fast, reversible, and may be performed up to hundreds of cycles before photobleaching occurs. These findings highlight that this method of electrochemical fluorescence switching can be incorporated into advanced fluorescence microscopy.

Chemiluminescent Probes Based on 1,2-Dioxetane Structures For Bioimaging.

Chemiluminescent probes based on 1,2-dioxetane scaffold are one of the most sensitive imaging modalities for detecting disease-related biomarkers and can obtain more accurate biological information in cells and in vivo. Due to the elimination of external light excitation, the background autofluorescence problem in fluorescence technology can be effectively avoided, providing ultrahigh sensitivity and signal-to-noise ratio for various applications. In this review, we highlight a comprehensive but concise overview of activatable 1,2-dioxetane-based chemiluminescent probes by reporting significant advances in accurate detection and bioimaging. The design principles and applications for reactive species, enzymes, and other disease-related biomarkers are systematically discussed and summarized. The challenges and potential prospects of chemiluminescent probes are also discussed to further promote the development of new chemiluminescence methods for biological analysis and diagnosis.