Integration of fluorescence and MALDI imaging for microfluidic chip-based screening of potential thrombin inhibitors from natural products.

The microfluidic technology provides an ideal platform for in situ screening of enzyme inhibitors and activators from natural products. This work described a surface-modified ITO glass-PDMS hybrid microfluidic chip for evaluating thrombin interaction with its potential inhibitors by fluorescence imaging and matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI). The fluorescence-labeled substrate was immobilized on a conductive ITO glass slide coated with gold nanoparticles/thiol-ß-cyclodextrin modified TiO2 nanowires (Au-ß-CD@TiO2 NWs) via Au-S bonds. A PDMS microchannel plate was placed on top of the modified ITO slide. The premixed solutions of thrombin and candidate thrombin inhibitors were infused into the microchannels to form a microreactor environment. The enzymatic reaction was rapidly monitored by fluorescence microscopy, and MALDI MS was used to validate and quantify the enzymatic hydrolysate of thrombin to determine the enzyme kinetic process and inhibitory activities of selected flavonoids. The fluorescence and MALDI MS results showed that luteolin, cynaroside, and baicalin have good thrombin inhibitory activity and their half-maximal inhibitory concentrations (IC50) were below 30 µM. The integration of fluorescence imaging and MALDI MSI for in situ monitoring and quantifying the enzymatic reaction in a microfluidic chip is capable of rapid and accurate screening of thrombin inhibitors from natural products.

Abnormal gray matter volume and functional connectivity patterns in social cognition-related brain regions of young children with autism spectrum disorder.

Autism spectrum disorder (ASD) is associated with abnormal brain imaging findings, but descriptions thereof are inconsistent. The aim of the present study was to investigate brain abnormalities in young children with ASD using a combination of structural and functional brain magnetic resonance imaging (MRI). Structural and resting-state functional MRI was performed in 67 children with ASD (aged 2-7 years) and 39 age-matched typically developing (TD) controls. Voxel-based morphometry was used to evaluate differences in brain structure between groups. Topologic parameters of the functional brain network were compared by graph theoretic analysis and network connectomes were compared with network-based statistics. A support vector machine (SVM) was used to discriminate between ASD and TD groups. Results demonstrated young children with ASD had increased gray matter volumes (GMVs) in the right medial superior frontal gyrus and left fusiform gyrus compared with the TD group. The ASD group had altered subnetwork connectivity in frontal and temporal lobes and other social cognition-related brain regions. Functional connectivity in the left superior temporal gyrus and left temporal pole of the middle temporal gyrus was positively correlated with adaptability and language developmental quotient (DQ) in children with ASD. The combination of the brain structural and functional features had 86.2% accuracy in discriminating between ASD and TD. The present study shows that young children with ASD have altered GMVs and functional networks in social cognition-related brain regions, which are potential neuroimaging biomarkers for ASD.

Monolithic Gold Nanoparticles/Thiol-ß-cyclodextrin-Functionalized TiO2 Nanowires for Enhanced SALDI MS Detection and Imaging of Natural Products.

Surface-assisted laser desorption/ionization mass spectrometry (SALDI MS) has been successfully applied in the analysis of various small molecules. In this work, gold nanoparticles/thiol-ß-cyclodextrin-functionalized TiO2 nanowires (AuNPs/SH-ß-CD-TiO2 NWs) were prepared to enhance the performance of SALDI MS and mass spectrometry imaging (MSI). A monolithic TiO2 film was first grown on an indium tin oxide (ITO) glass slide via a modified sol-gel method and treated in an alkaline environment to form nanowires. TiO2 NWs were chemically modified by SH-ß-CD for immobilizing AuNPs densely and strongly. Compared with the conventional organic matrix 2,5-dihydroxybenzoic acid (DHB), the prepared AuNPs/SH-ß-CD-TiO2 NWs showed superior performances on detection sensitivity, repeatability, and analyte coverage. Analytes typically detectable with negative-ion matrix-assisted laser desorption/ionization (MALDI) MS could also be observed using AuNPs/SH-ß-CD-TiO2 NWs in the positive ion mode. Its successful usage efficiently enhanced the SALDI MS detection of various small molecules such as carbohydrates, fatty acids, and bile acids in the positive ion mode. The developed SALDI substrate was further used to characterize and discriminate the natural and in vitro cultured Calculus Bovis, as well as natural and artificial Moschus. Furthermore, the spatial distribution of several natural products in spearmint leaves and potato tubers was explored by tissue imprinting and deposition on the AuNPs/SH-ß-CD-TiO2 NW surface for SALDI MSI in dual-polarity mode, respectively. The wide application and satisfied detection sensitivity make AuNPs/SH-ß-CD-TiO2 NWs ideal for SALDI MS and MSI of various natural products.

Porous TiO2 Film Immobilized with Gold Nanoparticles for Dual-Polarity SALDI MS Detection and Imaging.

Surface-assisted laser desorption/ionization (SALDI) mass spectrometry (MS) has become an attractive complementary approach to matrix-assisted laser desorption/ionization (MALDI) MS. SALDI MS has great potential for the detection of small molecules because of the absence of applied matrix. In this work, a functionalized porous TiO2 film immobilized with gold nanoparticles (AuNPs-FPTDF) was prepared to enhance SALDI MS performance. The porous TiO2 films were prepared by the facile sol-gel method and chemically functionalized for dense loading of AuNPs. The prepared AuNPs-FPTDF showed superior performance in the detection and imaging of small molecules in dual-polarity modes, with high detection sensitivity in the low pmol range, good repeatability, and low background noise compared to common organic MALDI matrixes. Its usage efficiently enhanced SALDI MS detection of various small molecules, such as amino acids and neurotransmitters, fatty acids, saccharides, alkaloids, and flavonoids, as compared with α-cyano-4-hydroxycinnamic acid, 9-aminoacridine, and the three precursor substrates of AuNPs-FPTDF. In addition, the blood glucose level in rats was successfully determined from a linearity concentration range of 0.5-9 mM, as well as other biomarkers in rat serum with SALDI MS. More importantly, the spatial distribution of metabolites from the intact flowers of the medicinal plant Catharanthus roseus was explored by using the AuNPs-FPTDF as an imprint SALDI MS substrate in dual-polarity modes. These results demonstrate wide applications and superior performances of the AuNPs-FPTDF as a multifunctional SALDI surface with enhanced detection sensitivity and imaging capabilities.

Design, synthesis chalcone derivatives as AdipoR agonist for type 2 diabetes.

Two structurally novel series of chalcone derivatives were designed and synthesized as potential agents against type 2 diabetes. As a result of the antidiabetic biological evaluation in streptozotocin (STZ)-induced type 2 diabetes animal model, 13e, 13g, and 19f showed more significant reduction in serum Glu, TG, TC levels by contrast to the positive control AdipoRon. In addition to upregulating the expression of AdipoR1 and AdipoR2, 13e and 19f treatment also increased expression of AMPK and PPAR-α. Taken together, these results suggested that 13e and 19f might be a promising compound for type 2 diabetes treatment.