A fluorescent probe for selective detection of boric acids and its application for screening the conversion of the Suzuki-Miyaura coupling reaction.

Boric acid (B(OH)3) plays an important physiological role and is widely used as a food preservative and an antiseptic. Various colorimetric, fluorescent probes have been developed to detect boric acid; however, most of them could not discriminate boric acid over boronic acids (R-B(OH)2) or are limited to boronic acid sensors. Therefore, the development of boric acid-selective probes is necessary. Herein, a salicylimine-based fluorophore, Di-OH, was designed that showed selective fluorescence response to boric acid over boronic acid. Its fluorescence response to boric acid showed a large fluorescence turn-on signal up to 140 fold and excellent selectivity with various analytes. Furthermore, since boric acid is generated in proportion to the consumed boronic acid derivatives during reactions involving oraganoboron compounds, Di-OH allowed the determination of the conversion of the Suzuki-Miyaura coupling reaction using fluorescence spectroscopy and its correlation with the GC conversion was confirmed.

Co-functionalization with phosphate and carboxylate on polydiacetylene for colorimetric detection of calcium ions in serum.

In this study, co-functionalization with phosphate and carboxylate on polydiacetylene (PDA) was proposed to detect calcium ions in serum, inspired by biologically abundant phosphate-calcium ion and carboxylate-calcium ion binding. The cooperative interaction of calcium ions with phosphate and carboxylate in PDA induced the change of electronic properties in the backbone without aggregation of liposomes, accompanied by blue-to-purple color transition. The cooperative effect through the introduction of mixed ligands facilitated the selective detection of calcium ions over magnesium ions, which was a source of major interference in many calcium ion probes, and in the presence of major serum metal ions. The sensor system exhibited highly sensitive detection of calcium ions with an estimated limit of detection of 0.97 µM. In addition, the detection method was employed to determine the concentration of calcium ions in various serums.

Paper-Based Colorimetric Sensor System for High-Throughput Screening of C-H Borylation.

A paper-based colorimetric sensor system (PBCSS) was developed to detect the amount of bis(pinacolato)diboron (B2 Pin2 ) and applied as a high-throughput screening protocol in Ir-catalyzed C-H borylation. First, 96 ligands were screened for the borylation of benzene, and then 12 of them were selected and tested for five substrates. These reaction mixtures were spotted in the PBCSS, showing a blue-violet color. The value of the gray scale of each reaction was obtained from these colored spots and converted to the extent of conversion of B2 Pin2 . The extents of conversion of B2 Pin2 obtained from the PBCSS showed good correlation with those obtained from gas chromatography analysis. In addition, the modified conversion using blank data showed good correlation with the yield of products.

High-Throughput Screening Protocol for the Coupling Reactions of Aryl Halides Using a Colorimetric Chemosensor for Halide Ions.

Mercury complex of 4-(2-pyridylazo)resorcinol (PAR-2Hg(2+)), a halide-ion chemosensor, was prepared and its efficiency as a tool for high-throughput screening (HTS) of transition-metal-catalyzed coupling reactions was investigated. It showed a high selectivity for halide ions. When the PAR-2Hg(2+) complex was used in the Suzuki coupling reaction and C-H activated coupling reaction with aryl bromides, the quantitative and qualitative conversions of aryl halides were obtained from the reaction mixture color change.

A fluorescence-based glycosyltransferase assay for high-throughput screening.

Glycosyltransferases catalyze the transfer of a monosaccharide unit from a nucleotide or lipid sugar donor to polysaccharides, lipids, and proteins in a stereospecific manner. Considerable effort has been invested in engineering glycosyltransferases to diversify sugar-containing drugs. An important requirement for glycosyltransferase engineering is the availability of a glycosyltransferase assay system for high-throughput screening of glycosyltransferase mutants. In this study, a general glycosyltransferase assay system was developed based on an ATP sensor. This system showed submicromolar sensitivity and compatibility with both purified enzymes and crude cell extracts. The assay system will be useful for glycosyltransferase engineering based on high-throughput screening, as well as for general glycosyltransferase assays and kinetics.

A highly sensitive gold nanoparticle-based colorimetric probe for pyrophosphate using a competition assay approach.

In this study, a mixture of [Zn(2)(1,3-bis[bis(2-pyridylmethyl)aminomethyl]benzene)](4+) ([Zn(2)(BBPAB)](4+)) and 11-mercaptoundecylphosphoric acid functionalized gold nanoparticles (Phos-AuNPs) is shown to be a highly sensitive colorimetric probe that can easily detect pyrophosphate (PPi) at less than 200 nM with the naked eye.

A bi-ligand co-functionalized gold nanoparticles-based calcium ion probe and its application to the detection of calcium ions in serum.

In this study, the use of bi-ligand co-functionalized gold nanoparticles in a highly selective and sensitive colorimetric probe for Ca(2+) ions is demonstrated and this probe also determined the concentrations of Ca(2+) ions in serum samples.

A simple, fast, and easy assay for transition metal-catalyzed coupling reactions using a paper-based colorimetric iodide sensor.

A paper-based colorimetric iodide sensor (PBCIS) that consists of filter paper treated with starch and an oxidant is developed. It has been employed as a protocol to obtain the extent of conversion of aryl iodides in C-C, C-N, C-O and C-S bond formations, including polymer-supported Heck reactions, by transition metal catalysts such as palladium, nickel and copper.

Delivery of shRNA using gold nanoparticle-DNA oligonucleotide conjugates as a universal carrier.

The efficient delivery of nucleic acids into mammalian cells is a central aspect of research involving cell biology and medical applications, including the clinical treatment of genetic disorders. We report an efficient small hairpin RNA (shRNA) delivery system that utilizes a single species of gold nanoparticle-DNA oligonucleotide conjugate (AuNP-DNA oligo) as a universal carrier. In vitro synthesized shRNA that is specific to the p53 gene was efficiently delivered into HEK293 and HeLa human cell lines using an AuNP-DNA oligo. The delivery resulted in an 80-90% knockdown of p53 expression. The same AuNP-DNA oligo was also efficient for the delivery of another shRNA, which is specific to the Mcl-1 gene, as well as the repression of MCL-1 expression. The knockdown efficiency of shRNA that was delivered using an AuNP-DNA oligo was comparable with that of a liposome-based shRNA delivery method. Our results offer an alternate delivery system for shRNA that can be used on any gene of interest.