Aggregation-Induced Emission Probe for Light-Up and in Situ Detection of Calcium Ions at High Concentration

The fluorescent probe for the detection of calcium ions is an indispensable tool in the biomedical field. The millimolar order of Ca­(II) ions is associated with many physiological processes and diseases, such as hypercalcemia, soft tissue calcification, and bone microcracks. However, the conventional fluorescent probes are only suitable for imaging Ca­(II) ions in the nanomolar to micromolar range, which can be because of their high affinities toward Ca­(II) ions and aggregation-caused quenching drawbacks. To tackle this challenge, we herein develop an aggregation-induced emission (AIE) probe SA-4CO₂Na for selective and light-up detection of Ca­(II) ions in the millimolar range (0.6–3.0 mM), which can efficiently distinguish between hypercalcemic (1.4–3.0 mM) and normal (1.0–1.4 mM) Ca²⁺ ion levels. The formation of fibrillar aggregates between SA-4CO₂Na and Ca­(II) ions was clearly verified by fluorescence, scanning electron microscopy, and transmission electron analysis. Moreover, this AIE-active probe can be used for wash-free and light-up imaging of a high concentration of Ca­(II) ions even in the solid analytes, including calcium deposits in psammomatous meningioma slice, microcracks on bovine bone surface, and microdefects on hydroxyapatite-based scaffold. It is thus expected that this AIE-active probe would have broad biomedical applications through light-up imaging and sensing of Ca­(II) ions at the millimolar level

Research on driver’s anger recognition method based on multimodal data fusion

This paper aims to address the challenge of low accuracy in single-modal driver anger recognition by introducing a multimodal driver anger recognition model. The primary objective is to develop a multimodal fusion recognition method for identifying driver anger, focusing on electrocardiographic (ECG) signals and driving behavior signals. Emotion-inducing experiments were performed employing a driving simulator to capture both ECG signals and driving behavioral signals from drivers experiencing both angry and calm moods. An analysis of characteristic relationships and feature extraction was conducted on ECG signals and driving behavior signals related to driving anger. Seventeen effective feature indicators for recognizing driving anger were chosen to construct a dataset for driver anger. A binary classification model for recognizing driving anger was developed utilizing the Support Vector Machine (SVM) algorithm. Multimodal fusion demonstrated significant advantages over single-modal approaches in emotion recognition. The SVM-DS model using decision-level fusion had the highest accuracy of 84.75%. Compared with the driver anger emotion recognition model based on unimodal ECG features, unimodal driving behavior features, and multimodal feature layer fusion, the accuracy increased by 9.10%, 4.15%, and 0.8%, respectively. The proposed multimodal recognition model, incorporating ECG and driving behavior signals, effectively identifies driving anger. The research results provide theoretical and technical support for the establishment of a driver anger system.</p

C-Abl Inhibitor Imatinib Enhances Insulin Production by β Cells: C-Abl Negatively Regulates Insulin Production via Interfering with the Expression of NKx2.2 and GLUT-2

<div><p>Chronic myelogenous leukemia patients treated with tyrosine kinase inhibitor, Imatinib, were shown to have increased serum levels of C-peptide. Imatinib specifically inhibits the tyrosine kinase, c-Abl. However, the mechanism of how Imatinib treatment can lead to increased insulin level is unclear. Specifically, there is little investigation into whether Imatinib directly affects β cells to promote insulin production. In this study, we showed that Imatinib significantly induced insulin expression in both glucose-stimulated and resting β cells. In line with this finding, c-Abl knockdown by siRNA and overexpression of c-Abl markedly enhanced and inhibited insulin expression in β cells, respectively. Unexpectedly, high concentrations of glucose significantly induced c-Abl expression, suggesting c-Abl may play a role in balancing insulin production during glucose stimulation. Further studies demonstrated that c-Abl inhibition did not affect the major insulin gene transcription factor, pancreatic and duodenal homeobox-1 (PDX-1) expression. Of interest, inhibition of c-Abl enhanced NKx2.2 and overexpression of c-Abl in β cells markedly down-regulated NKx2.2, which is a positive regulator for insulin gene expression. Additionally, we found that c-Abl inhibition significantly enhanced the expression of glucose transporter GLUT2 on β cells. Our study demonstrates a previously unrecognized mechanism that controls insulin expression through c-Abl-regulated NKx2.2 and GLUT2. Therapeutic targeting β cell c-Abl could be employed in the treatment of diabetes or β cell tumor, insulinoma.</p></div

Inhibition of c-Abl significantly enhance glucose-stimulated insulin production by β cells.

<p><b>A</b>. NIT-1 cells were cultured in the low glucose media (glucose 4.5 mM) with glucose 8 mM, 16 mM, 8 mM plus Imatinib 3 µM or 16 mM plus Imatinib 3 µM for 6 hrs. The insulin concentration was measured using ELISA. The similar results were obtained in 3 independent experiments. Two-way ANOVA with Bonferroni post-test was performed. <b>B</b>. NIT-1 cells were cultured in the low glucose media (glucose 4.5 mM) with glucose 16 mM or 16 mM plus Imatinib 3 µM for 6 hrs, insulin gene expression was examined by real-time RT-PCR. The levels of insulin gene expression were normalized relative to β actin. The results were reproduced in 3 independent experiments. Student t test was performed. <b>C</b>. In the cultures of <b>B</b> above, C-peptide concentration in each incuation was examined using ELISA. Student t test was performed. <b>D</b>. NIT-1 cells were transfected with c-Abl siRNA or control siRNA for 24 hrs, then were stimulated with 16 mM glucose for 6 hrs. Insulin gene expression was examined by real-time RT-PCR, the data were calculated relative to the group with NIT-1 cells transfected with control siRNA without glucose stimulation. Three independent experiments were performed with similar results. Student t test was performed. *: p<0.05, **:p<0.01,***:p<0.001.</p

C-Abl regulates insulin gene expression via NKx2.2.

<p><b>A</b>. NIT-1 cells were tranduced with retrovirus vector encoding c-Abl gene to overexpress c-Abl or control cDNA. Twenty-four hrs later, the cells were examined for the gene expression of insulin, PDX-1, NKx6.1, NKx2.2, respectively by real-time RT-PCR. The PCR results were normalized relative to β actin for each individual gene, and the relative values of c-Abl transduced cells were compared to those of control cDNA transduced cells which were defined as 1 (the white bar). The results shown were from a representative of 3 independent experiments. One-way ANOVA with post hoc test was performed. *: p>0.05, **:p<0.01, ***:p<0.001. <b>B</b>. NIT-1 cells were cultured in the low glucose DMEM medium alone (Immatinib 0 µM), or in the presence of 0.3 µM Imatinib, or 3 µM Imatinib (3 µM) for 24 hrs. The protein levels of NKx2.2 were examined by Western blot. The densitometry was analyzed relative to the levels of β-actin, and the relative level of the cells incubated with 0 µM Imatinib was defined as 1.</p

Inhibition of c-Abl promotes insulin production by β cells in resting state.

<p>NIT-1 cells were cultured in low glucose DMEM medium (glucose 4.5 mM) for a few days. <b>A</b>. The NIT-1 cells were harvested and then cultured in low glucose DMEM medium with different conditions: Imatinib 0 µM, 0.3 µM, 1 µM or 3 µM for 6 hrs. The supernatants from all cultures were harvested and measured for insulin production by ELISA. The results presented were from a representative of three independent experiments. Two-way ANOVA with Bonferroni post-test was performed. <b>B</b>. The NIT-1 cells were cultured in low glucose DMEM medium with Imatinib 0 µM, 0.3 µM or 1 µM for 6 hrs. The insulin gene expression was examined by real-time RT-PCR. The levels of insulin gene expression were normalized relative to β actin. The experiments were repeated 3 times with reproducible results. Two-way ANOVA with Bonferroni post-test was performed. <b>C</b>. NIT-1 cells were transfected with c-Abl siRNA or control siRNA for 24 hrs. Then the transfected cells were cultured in low glucose DMEM medium for 6 hrs. An additional group was also included by culturing c-Abl siRNA transfected NIT-1 cells with 1 µM Imatinib. The supernatants were harvested from the above cultures and the insulin concentration was examined by ELISA. One-way ANOVA with post hoc test was performed. Similar results were obtained from at least 3 independent experiments. *: p<0.05, **:p<0.01,***:p<0.001.</p

Glucose stimulation induces up-regulation of both c-Abl and insulin expression.

<p><b>A</b> . NIT-1 cells were cultured in low glucose DMEM medium with or without glucose 16 mM for 6 hrs. Thereafter, the cells were examined for c-Abl and insulin gene expression using real-time RT-PCR. Student t test was performed. The results shown were from a representative of 3 independent experiments. *: p>0.05, **:p<0.001. <b>B.</b> NIT-1 cells were cultured in low glucose DMEM medium with or without glucose 16 mM for 24 hrs. Then, the cells were cytospun onto slides and stained with anti-c-Abl antibodies and Dappi, and visualized by a fluorescent microscope (Zeiss Axioskop). A representative image of three slides in each group is shown.</p

Relationship between c-Abl and insulin gene transcription factor PDX-1.

<p><b>A</b>. NIT-1 cells were cultured in the low glucose DMEM medium, or with glucose (16 mM) or with Imatinib (3 µM) for 6 hrs. The cells in each group were harvested and the expression of PDX-1 was examined by real-time RT-PCR. The results shown were from a representative of 3 independent experiments. <b>B</b>. NIT-1 cells were cultured in the low glucose DMEM medium with different concentrations of Imatinib (0, 0.3, 1, 3 µM) for 24 hrs. Then, the protein levels of PDX-1 and GAPDH were examined by Western blot. Relative quantity of each PDX-1 band relative to its GAPDH control was shown below the Westerblot image. These results were reproduced by additional two experiments. <b>C</b>. 293 cell line were transfected with pdx-1 promoter-driven luciferase reporter gene, together with transfection of plasmids encoding <i>c-Abl</i> gene or control plasmids. Twenty four hrs later, the cells from the above conditions were harvested and luciferase activities were measured by using the Dual Luciferase Reporter Kit. This experiment was repeated twice with similar results. The targeted gene expression levels were normalized relative to β actin. One-way ANOVA with post hoc test was performed. *: p>0.05, **:p<0.001.</p

Fluorescent Light-Up Detection of Amine Vapors Based on Aggregation-Induced Emission

Amines play vital roles in agricultural, pharmaceutical, and food industries, but volatile amine vapors are serious threats to human health. Previously reported fluorescent sensors for amine vapor detection usually suffer from aggregation-caused quenching (ACQ) effect and need to be dispersed in solution or matrix materials. Herein, based on the fluorogen of 2-(2-hydroxyphenyl)­quinazolin-4­(3<i>H</i>)-one (HPQ) with aggregation-induced emission (AIE) properties, we have developed a fluorescent sensor HPQ-Ac for light-up detection of amine vapors through aminolysis reaction. The portable HPQ-Ac sensor can be easily prepared by directly depositing on filter paper, and it can only light up via exposure to amine vapors among various volatile organic compounds. Taking advantage of its portability and high sensitivity for amine vapors, HPQ-Ac sensor can also be used for food spoilage detection and fluorescent invisible ink

Aggregation-Induced Emission Luminogen with Deep-Red Emission for Through-Skull Three-Photon Fluorescence Imaging of Mouse

Imaging the brain with high integrity is of great importance to neuroscience and related applications. X-ray computed tomography (CT) and magnetic resonance imaging (MRI) are two clinically used modalities for deep-penetration brain imaging. However, their spatial resolution is quite limited. Two-photon fluorescence microscopic (2PFM) imaging with its femtosecond (fs) excitation wavelength in the traditional near-infrared (NIR) region (700–1000 nm) is able to realize deep-tissue and high-resolution brain imaging. However, it requires craniotomy and cranial window or skull-thinning techniques due to photon scattering of the excitation light. Herein, based on a type of aggregation-induced emission luminogen (AIEgen) DCDPP-2TPA with a large three-photon absorption (3PA) cross section at 1550 nm and deep-red emission, we realized through-skull three-photon fluorescence microscopic (3PFM) imaging of mouse cerebral vasculature without craniotomy and skull-thinning. Reduced photon scattering of a 1550 nm fs excitation laser allowed it to effectively penetrate the skull and tightly focus onto DCDPP-2TPA nanoparticles (NPs) in the cerebral vasculature, generating bright three-photon fluorescence (3PF) signals. <i>In vivo</i> 3PF images of the cerebral vasculature at various vertical depths were obtained, and a vivid 3D reconstruction of the vascular architecture beneath the skull was built. As deep as 300 μm beneath the skull, small blood vessels of 2.4 μm could still be recognized