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.
Yin
Xue-Bo
XB
State Key Laboratory of Electroanalytical Chemistry, Changchun Insititute of Applied Chemistry, Chinese Academy of Science, Changchun, 130022, China.
Qi
Bin
B
Sun
Xuping
X
Yang
Xiurong
X
Wang
Erkang
E
D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives / Q000737:chemistry; D015097:3-Mercaptopropionic Acid / Q000737:chemistry; D000327:Adsorption; D000818:Animals; D001360:Avidin / Q000737:chemistry; D002417:Cattle; D056831:Coordination Complexes; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D007074:Immunoglobulin G / Q000032:analysis*; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000032:analysis*; D013499:Surface Properties; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D017975:Ruthenium Compounds
D015082:2,2'-Dipyridyl; D015097:3-Mercaptopropionic Acid; D001360:Avidin; D056831:Coordination Complexes; D006046:Gold; D007074:Immunoglobulin G; D012710:Serum Albumin, Bovine; D005680:gamma-Aminobutyric Acid; C547232:tris(2,2-bipyridine)-ruthenium(II); D017975:Ruthenium Compounds; C518401:4-(dimethylamino)butyric acid