Biomedical subjects

Bin Qi

Publications and source records attributed to Bin Qi.

4 recordsLinked to original sources

PubMed2006

Synthesis of PtNPs/AQ/Ru(bpy)3(2+) colloid and its application as a sensitive solid-state electrochemiluminescence sensor material.

The facile synthesis of the novel platinum nanoparticles/Eastman AQ55D/ruthenium(II) tris(bipyridine) (PtNPs/AQ/Ru(bpy)3(2+)) colloidal material for ultrasensitive ECL solid-state sensors was reported for the first time. The cation ion-exchanger AQ was used not only to immobilize ECL active species Ru(bpy)3(2+) but also as the dispersant of PtNPs. Colloidal characterization was accomplished by transmission electron microscopy (TEM), X-ray photoelectron spectrum (XPS), and UV-vis spectroscopy. Directly coating the as-prepared colloid on the surface of a glassy carbon electrode produces an electrochemiluminescence (ECL) sensor. The electronic conductivity and electroactivity of PtNPs in composite film made the sensor exhibit faster electron transfer, higher ECL intensity of Ru(bpy)3(2+), and a shorter equilibration time than Ru(bpy)3(2+) immobilized in pure AQ film. Furthermore, it was demonstrated that the combination of PtNPs and permselective cation exchanger made the sensor exhibite excellent ECL behavior and stability and a very low limit of detection (1 x 10(-15) M) of tripropylamine with application prospects in bioanalysis. This method was very simple, effective, and low cost.

Journal Article↗

PubMed2006

A calibration method for measurement of small alkyl organic peroxy radicals by chemical amplifier.

A new method is proposed to determine the calibration factor (CF) of methyl and ethyl peroxy radicals in a chemical amplifier. The radical source comes from the reactions of excess methane and ethane, respectively, with known concentrations of OH radicals generated by the photolysis of water vapor at 184.9 nm in air in a flow tube. This yields a mixed radical source with equal amounts of HO2 and RO2 (R = CH3, C2H5). The CF for RO2 can be derived from the CF for HO2 and an average CF for the mixed radicals. The reliability of the method was evaluated by comparing the CF ratios of RO2 to HO2 obtained from both the experiments and theoretical calculations.

Journal Article↗

PubMed2005

4-(Dimethylamino)butyric acid labeling for electrochemiluminescence detection of biological substances by increasing sensitivity with gold nanoparticle amplification.

4-(Dimethylamino)butyric acid (DMBA) labeling combined with gold nanoparticle amplification for electrochemiluminescence (ECL) determination of a biological substance (bovine serum albumin (BSA) and immunoglobulin G (IgG) as models) was presented. After DMBA, an analogue of tripropylamine, was tagged on the (anti)analytes, an ECL signal related to the content of the analytes was generated when the analyte tagged with DMBA was in contact with tris(2,2'-bipyridine)ruthenium (Ru(bpy)(3)2+) solution and a potential was applied. To improve the adsorption capacity, a gold nanoparticle layer was first combined into the surface of the 2-mm-diameter gold electrode. For the determination of BSA, avidin was covalently conjugated to a self-assembled monolayer of 3-mercaptopropanoic acid on the gold nanoparticle layer. Biotinylated BSA-DMBA was then immobilized on the gold nanoparticle layer of the gold electrode via the avidin-biotin reaction. IgG was tested via a typical sandwich-type immobilization method. ECL signals were generated from the electrodes immobilized with BSA or IgG by immersing them in a 1 mmol L-1 Ru(bpy)(3)2+ solution and scanning from 0.5 to 1.3 V versus Ag/AgCl. With gold nanoparticle amplification, the ECL peak intensity was proportional to the concentration over the range 1-80 and 5-100 microg/mL for BSA and IgG consuming 50 microL of sample, respectively. A 10- and 6-fold sensitivity enhancement was obtained for BSA and IgG over their direct immobilization on an electrode using DMBA labeling. The relative standard deviations of five replicate determinations of 10 microg/mL BSA and 20 microg/mL IgG were 8.4 and 10.2%, respectively. High biocompatibility and low cost were the main advantages of the present DMBA labeling technique over the traditional Ru(bpy)(3)2+ labeling.

2,2'-Dipyridyl↗

PubMed2003

A strategy for constructing a hybrid bilayer membrane based on a carbon substrate.

We construct a hybrid bilayer membrane (HBM) on a new substrate-carbon electrode. It is an extension of HBM based on other substrates. Primary alkylamine was chemically modified onto the surface of a carbon electrode by electrochemical scans; thus, a monolayer was formed on the electrode. Because the alkane chains section is toward the outside, a hydrophobic surface was constructed. Then a lipid monolayer was spread on the hydrophobic surface of the carbon electrode. The formed HBM was characterized by electrochemical and ATR-FT-IR methods. From ATR-FT-IR results, the lipid order parameter (S) of 0.73 was obtained. This kind of hybrid membrane has the advantages of a lipid/alkanethiol HBM. A potential application of this HBM as a biosensor (detecting K+) was given.

Journal Article↗