Antenna effect of pyridoxal phosphate on the fluorescence of mitoxantrone-silicon nanoparticles and its application in alkaline phosphatase assay.

As a kind of sensing and imaging fluorescent probe with the merit of low toxicity, good stability, and environment-friendly, silicon nanoparticles (SiNPs) are currently attracting extensive research. In this work, we obtained mitoxantrone-SiNPs (MXT-SiNPs) with green emission by one-pot synthesis under mild temperature condition. The antenna based on pyridoxal phosphate (PLP) was designed for light-harvesting to enhance the luminescence of MXT-SiNPs and to establish a novel sensing strategy for alkaline phosphatase (ALP).

Gold nanoclusters/graphene quantum dots complex-based dual-emitting ratiometric fluorescence probe for the determination of glucose.

Herein, we report the design of a single-excitation/double-emission ratiometric fluorescence nanosensor for the determination of glucose. The sensing system combines glucose oxidation catalyzed by glucose oxidase, Fenton chemistry, Fe-sensitive fluorescent gold nanoclusters (AuNCs), and Fe-inert fluorescent graphene quantum dots (GQDs). We used orange-fluorescent AuNCs co-modified with bovine serum albumin and 3-mercaptopropionic acid as the indicator probe, and GQDs with the same excitation wavelength as the BSA/MPA-AuNCs, but with different emission wavelength, as the reference probe.

Fabrication of ultra-small monolayer graphene quantum dots by pyrolysis of trisodium citrate for fluorescent cell imaging.

Background: The preparation and biological applications of ultra-small graphene quantum dots (GQDs) with accurate-controlled size are of great significance.

Methods: Here in, we report a novel procedure involving pyrolysis of trisodium citrate and subsequent ultrafiltration for fabricating monolayer GQDs with ultra-small lateral size (1.3±0.

Preparation of strongly fluorescent water-soluble dithiothreitol modified gold nanoclusters coated with carboxychitosan, and their application to fluorometric determination of the immunosuppressive 6-mercaptopurine.

Water-soluble and non-aggregating gold nanoclusters (AuNCs) were obtained by modification of the AuNCs with dithiothreitol (DTT) and then coating them with carboxylated chitosan. This process remarkably enhances the dispersibility of DTT-coated AuNCs in water. The resulting AuNCs, on photoexcitation at 285 nm, display strong red emission with a maximum at 650 nm and a 23% quantum yield.

Chitosan-stabilized platinum nanoparticles as effective oxidase mimics for colorimetric detection of acid phosphatase.

Capping molecules on the surface of nanomaterials not only enhance the dispersion and stability of nanomaterials but also greatly facilitate their surface modification and biological applications. However, most capping molecules can severely block the active sites of the catalytic core, thereby decreasing the enzymatic activity of nanomaterial-based enzyme mimics. This work demonstrates the superiority of chitosan (Ch) as a capping molecule for synthesizing catalytic platinum nanoparticles (PtNPs).

Partially reduced graphene oxide as highly efficient DNA nanoprobe.

This work investigates the effect of reduction degree on graphene oxide (GO)-DNA interaction and the fluorescence quenching mechanism. Partial reduced graphene oxide (pRGO), which maintains well water-dispersibility, is synthesized using a mild reduction method by incubating GO suspension under alkaline condition at room temperature. The fluorescence quenching enhances with the restoration degree of sp(2) carbon bonds and follows the static quenching mechanism.

[Chemical constituents of leaves of Panax japonicus var. major].

Seven compounds were isolated from the leaves of Panax japonicus var. major by chromatographic methods including silica gel, Sephadex LH-20, ODS and semi-preparative HPLC. Their structures were elucidated by their physical and chemical properties and spectral data analysis as 5, 7-dihydroxy-8-methoxyl flavone (1), ginsenoside Rs2 (2), quinquenoside R1 (3), ginsenoside Rs1 (4), notoginsenoside Fe (5), ginsenoside Rd2 (6) and gypenosiden IX (7).

Fluorescent hydrogen peroxide sensor based on cupric oxide nanoparticles and its application for glucose and L-lactate detection.

A novel fluorescent hydrogen peroxide sensor was developed based on the peroxidase-like activity of cupric oxide nanoparticles. Cupric oxide nanoparticles effectively catalyzed the decomposition of hydrogen peroxide into hydroxyl radicals. Then terephthalic acid was oxidized by hydroxyl radical to form a highly fluorescent product.

Bovine serum albumin-based probe carrier platform for electrochemical DNA biosensing.

A bovine serum albumin (BSA)-monolayer-based probe carrier platform is shown to improve the performance of a conventional thiolated single-stranded DNA probe self-assembled-monolayer-based electrochemical DNA hybridization biosensor. A detection limit of 0.5 fM can be obtained in a very reproducible manner (relative standard deviation <5%), along with high specificity.

Ultrasensitive and facile electrochemical deoxyribonucleic acid biosensor based on the conformational change of the recognition interface.

An ultrasensitive electrochemical impedance spectroscopic deoxyribonucleic acid biosensor has been developed based on the conformational change of the deoxyribonucleic acid recognition interface with lodging probes. Pairing process leads to desorption of deoxyribonucleic acid bases from the gold surface, leading to a significant change of the interfacial conformation and the charge transfer resistance. Remarkably low detection limits down to 40 fM are thus obtained without any additional amplification step.