title: A glucose oxidase-coupled DNAzyme sensor for glucose detection in tears and saliva.
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.
authors: Key Lab for Molecular Enzymology & Engineering of the Ministry of Education, School of Life Science, Jilin University, Qianjin Street 2699, Changchun 130012, China.
authors: Chengcheng
authors: C
authors: Liu
authors: Key Lab for Molecular Enzymology & Engineering of the Ministry of Education, School of Life Science, Jilin University, Qianjin Street 2699, Changchun 130012, China.
authors: Yongjie
authors: Y
authors: Sheng
authors: Key Lab for Molecular Enzymology & Engineering of the Ministry of Education, School of Life Science, Jilin University, Qianjin Street 2699, Changchun 130012, China.
authors: Yanhong
authors: Y
authors: Sun
authors: Key Lab for Molecular Enzymology & Engineering of the Ministry of Education, School of Life Science, Jilin University, Qianjin Street 2699, Changchun 130012, China.
authors: Junkui
authors: J
authors: Feng
authors: Key Lab for Molecular Enzymology & Engineering of the Ministry of Education, School of Life Science, Jilin University, Qianjin Street 2699, Changchun 130012, China.
authors: Shijin
authors: S
authors: Wang
authors: 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.
authors: Jin
authors: J
authors: Zhang
authors: Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA. Electronic address: jiacui2000@gmail.com.
authors: Jiacui
authors: J
authors: Xu
authors: 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.
authors: Dazhi
authors: D
authors: Jiang
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D021881:DNA, Catalytic / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005947:Glucose / Q000032:analysis* / Q000737:chemistry; D005949:Glucose Oxidase / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000032:analysis / Q000737:chemistry; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013666:Tears / Q000737:chemistry*
chemical_list: D021881:DNA, Catalytic; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase; D005947:Glucose
keywords: Glucose; Glucose oxidase; Non-invasive technology; Pistol-like DNAzyme; Saliva; Tear