title: Label-Free Detection of Telomerase Activity in Urine Using Telomerase-Responsive Porous Anodic Alumina Nanochannels.
abstract: Telomerase is closely related to cancers, which makes it one of the most widely known tumor marker. Recently, many methods have been reported for telomerase activity measurement in which complex label procedures were commonly used. In this paper, a label-free method for detection of telomerase activity in urine based on steric hindrance changes induced by confinement geometry in the porous anodic alumina (PAA) nanochannels was proposed. Telomerase substrate (TS) primer was first assembled on the inside wall of PAA nanochannels by Schiff reaction under mild conditions. Then, under the action of telomerase, TS primer was amplified and extended to repeating G-rich sequences (TTAGGG)x, which formed multiplex G-quadruplex in the presence of potassium ions (K(+)). This configurational change led to the increment of steric hindrance in the nanochannels, resulting in the decrement of anodic current of potassium ferricyanide (K3[Fe(CN)6]). Compared with previously reported methods based on PAA nanochannels (usually one G-quadruplex formed), multiplex repeating G-quadruplex formed on one TS primer in this work. As a result, large current drop (∼3.6 μA, 36%) was obtained, which gave facility to improve the detection sensitivity. The decreased ratio of anodic current has a linear correlation with the logarithm of HeLa cell number in the range of 10-5000 cells, with the detection limit of seven cells. The method is simple, reliable, and has been successfully applied in the detection of telomerase in urine with good accuracy, selectivity and reproducibility. In addition, the method is nondestructive test compared to blood analysis and pathology tests, which is significant for cancer discovery, development, and prognosis.
authors.affiliation: Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University , Nanjing, 211189, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Food Science and Technology, Henan University of Technology , Zhengzhou, 450001, China.
authors.forename: Min
authors.initials: M
authors.lastname: Wei
authors.affiliation: Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University , Nanjing, 211189, China.
authors.forename: Yuanjian
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University , Nanjing, 211189, China.
authors.forename: Bingjing
authors.initials: B
authors.lastname: Lv
authors.affiliation: Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University , Nanjing, 211189, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.affiliation: Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University , Nanjing, 211189, China.
authors.forename: Yuanjian
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University , Nanjing, 211189, China.
authors.forename: Songqin
authors.initials: S
authors.lastname: Liu
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D015374:Biosensing Techniques; D045744:Cell Line, Tumor; D055664:Electrochemical Techniques; D004566:Electrodes; D005292:Ferricyanides / Q000737:chemistry; D054856:G-Quadruplexes; D006367:HeLa Cells; D006801:Humans; D057230:Limit of Detection; D049329:Nanostructures / Q000737:chemistry*; D016062:Porosity; D015203:Reproducibility of Results; D013379:Substrate Specificity; D019098:Telomerase / Q000652:urine*
chemical_list: D005292:Ferricyanides; D019098:Telomerase; D000537:Aluminum Oxide; C028033:potassium ferricyanide