已为您找到该学者10条结果 成果回收站
鞠熀先, Zong Dai, †, Feng Yan, Jin Chen, † and Huangxian Ju*
Anal. Chem. 2003, 75, 5429-5434,-0001,():
-1年11月30日
-
48浏览
-
0点赞
-
0收藏
-
0分享
-
235下载
-
0
-
引用
鞠熀先, Jiuhong Yu, Songqin Liu, Huangxian Ju *
Biosensors and Bioelectronics 19(2003)509-514,-0001,():
-1年11月30日
A novel amperometric phenol sensor was constructed by immobilizing tyrosinase in a titania sol-gel matrix. The tyrosinase entrapped sol-gel film was obtained with a vapor deposition method, which simplified the traditional sol-gel process and avoided the shrinkage and cracking of conventional sol-gel-derived glasses. This matrix provided a microenvironment for retaining the native structure and activity of the entrapped enzyme and a very low mass transport barrier to the enzyme substrates. Phenol could be oxidized by dissolving oxygen in presence of immobilized tyrosinase to form a detectable product, which was determined at-150 mV without any mediator. The phenol sensor exhibited a fast response (less than 5 s) and sensitivity as high as 103μA/mM, which resulted from the porous structure and high enzyme loading of the sol-gel matrix. The linear range for phenol determination was from 1.2×10-7 to 2.6×10-4 M with a detection limit of 1.0×10-7M. The apparent Michaelis-Menten constant of the encapsulated tyrosinase was calculated to be (0.299±0.02) mM. The stability of the biosensor was also evaluated.
Sol-gel, Tyrosinase, Titania, Biosensors, Vapor deposition
-
30浏览
-
0点赞
-
0收藏
-
0分享
-
182下载
-
0
-
引用
鞠熀先, Dan Du a, Feng Yan b, Shengli Liu c, Huangxian Ju a, *
Journal of Immunological Methods 283(2003)67-75,-0001,():
-1年11月30日
We describe a novel electrochemical immunosensor for carbohydrate antigen 19-9 (CA19-9) based on the immobilization of CA19-9 with titania sol-gel on a graphite electrode (GE) by vapor deposition. The CA19-9 membrane was characterized using scanning electron microscopy and proved to be chemically clean, porous and homogeneous. The incubation of the immunosensor in a solution containing horseradish peroxidase (HRP)-labeled CA19-9 antibody led to the binding of HRP-labeled antibody with the immobilized antigen. The immobilized HRP catalyzed the oxidation of catechol by H2O2 and this provided a competitive method for the measurement of serum CA19-9. The response current decreased with increasing CA19-9 concentration in the incubation solution. The effects of pH, amount of HRP-labeled antibody, incubation time and temperature were explored to provide optimum analytical performance. Under optimal conditions, the current decrease of the immunosensor was proportional to CA19-9 concentrations in the range of 3-20 U/ml with a detection limit of 2.68 U/ml at a current decrease of 10%. The detection of CA19-9 in two serum samples obtained from clinically diagnosed patients with pancreatic carcinoma showed acceptable accuracy. The proposed immunosensor provides a new promising tool for the clinical immunoassay of CA19-9.
Immunosensor, Electrochemical sensors, Biosensors, Enzyme-labeled antibody, Carbohydrate antigen 19-9, CA19-9, Titania sol-gel, Pancreatic carcinoma
-
53浏览
-
0点赞
-
0收藏
-
0分享
-
296下载
-
0
-
引用
鞠熀先, Jianhua Zhao a*, Feng Yan a, Huangxian Ju b, *, Jinhai Tang c, Jianwei Qin c
Cancer Letters 204(2004)87-95,-0001,():
-1年11月30日
Serum vascular endothelial growth factor (VEGF) and endostatin levels were detected in 59 patients with breast cancer before surgery and at 3 weeks after surgery. Pre-operatively, their levels were significantly elevated and correlated with each other. Post-operatively, VEGF level decreased significantly and endostatin remained at a high level. Patients with both normalized VEGF and elevated endostatin following surgery had a lower risk of relapse than patients whose VEGF failed to normalize. Univariate and multivariate analyses showed a correlation between elevated VEGF level and short free-relapse survival. These findings suggest a new angiogenesis balance is formed in the patients after surgery and such a resultant balance may be beneficial for the prognosis of breast cancer, which deserves more extensive study.
Angiogenesis, Endostatin, Primary breast cancer, Vascular endothelial growth factor
-
42浏览
-
0点赞
-
0收藏
-
0分享
-
182下载
-
0
-
引用
鞠熀先, Huang-Xian Ju, a, *, Yong-Kang Ye, Jian-Hua Zhao, b and Yong-Lin Zhu a
Analytical Biochemistry 313(2003)255-261,-0001,():
-1年11月30日
A novel hepatitis B virus (HBV) DNA biosensor was developed by immobilizing covalently single-stranded HBV DNA fragments to a gold electrode surface via carboxylate ester to link the 3'-hydroxy end of the DNA with the carboxyl of the thioglycolic acid (TGA) monolayer. A short-stranded HBV DNA fragment (181 bp) of known sequence was obtained and amplified by PCR. The surface hybridization of the immobilized single-stranded HBV DNA fragment with its complementary DNA fragment was evidenced by electrochemical methods using [Os(bpy)2Cl2]+as a novel electroactive indicator. The formation of double-stranded HBV DNA on the gold electrode resulted in a great increase in the peak currents of [Os(bpy)2Cl2]+in comparison with those obtained at a bare or single-stranded HBV DNA-modified electrode. The mismatching experiment indicated that the surface hybridization was specific. The difference between the responses of [Os(bpy)2Cl2]+at single-stranded and double-stranded DNA/TGA gold electrodes suggested that the label-free hybridization biosensor could be conveniently used to monitor DNA hybridization with a high sensitivity. X-ray photoelectron spectrometry technique has been employed to characterize the immobilization of singlestranded HBV DNA on a gold surface.
Electrochemical DNA biosensor, Polymerase chain reaction, Hepatitis B virus, Hybridization, [Os(, bpy), 2Cl2]
-
29浏览
-
0点赞
-
0收藏
-
0分享
-
54下载
-
0
-
引用