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Biosens Bioelectron. 2015 Aug 15;70:455-61. doi: 10.1016/j.bios.2015.03.070. Epub 2015 Mar 30.

A glucose oxidase-coupled DNAzyme sensor for glucose detection in tears and saliva.

Author information

1
Key Lab for Molecular Enzymology & Engineering of the Ministry of Education, School of Life Science, Jilin University, Qianjin Street 2699, Changchun 130012, China.
2
Key Lab for Molecular Enzymology & Engineering of the Ministry of Education, School of Life Science, Jilin University, Qianjin Street 2699, Changchun 130012, China. Electronic address: zhangjin@jlu.edu.cn.
3
Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA. Electronic address: jiacui2000@gmail.com.
4
Key Lab for Molecular Enzymology & Engineering of the Ministry of Education, School of Life Science, Jilin University, Qianjin Street 2699, Changchun 130012, China. Electronic address: jiangdz@jlu.edu.cn.

Abstract

Biosensors have been widely investigated and utilized in a variety of fields ranging from environmental monitoring to clinical diagnostics. Glucose biosensors have triggered great interest and have been widely exploited since glucose determination is essential for diabetes diagnosis. In here, we designed a novel dual-enzyme biosensor composed of glucose oxidase (GOx) and pistol-like DNAzyme (PLDz) to detect glucose levels in tears and saliva. First, GOx, as a molecular recognition element, catalyzes the oxidation of glucose forming H2O2; then PLDz recognizes the produced H2O2 as a secondary signal and performs a self-cleavage reaction promoted by Mn(2+), Co(2+) and Cu(2+). Thus, detection of glucose could be realized by monitoring the cleavage rate of PLDz. The slope of the cleavage rate of PLDz versus glucose concentration curve was fitted with a Double Boltzmann equation, with a range of glucose from 100 nM to 10mM and a detection limit of 5 μM. We further applied the GOx-PLDz 1.0 biosensor for glucose detection in tears and saliva, glucose levels in which are 720±81 μM and 405±56 μM respectively. Therefore, the GOx-PLDz 1.0 biosensor is able to determine glucose levels in tears and saliva as a noninvasive glucose biosensor, which is important for diabetic patients with frequent/continuous glucose monitoring requirements. In addition, induction of DNAzyme provides a new approach in the development of glucose biosensors.

KEYWORDS:

Glucose; Glucose oxidase; Non-invasive technology; Pistol-like DNAzyme; Saliva; Tear

PMID:
25863343
DOI:
10.1016/j.bios.2015.03.070
[Indexed for MEDLINE]

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