Electrochemical aptamer-based determination of protein tyrosine kinase-7 using toehold-mediated strand displacement ampl
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ORIGINAL PAPER
Electrochemical aptamer-based determination of protein tyrosine kinase-7 using toehold-mediated strand displacement amplification on gold nanoparticles and graphene oxide Zongbing Li 1 & Zhengkun Zhou 1 & Ning Xue 1 & Shujie Wu 1 & Xiangmin Miao 1 Received: 28 April 2019 / Accepted: 17 September 2019 # Springer-Verlag GmbH Austria, part of Springer Nature 2019
Abstract An electrochemical method is described for ultrasensitive determination of protein tyrosine kinase-7 (PTK7). It is based on (a) the use of positively charged gold nanoparticles (AuNPs) and negatively charged graphene oxide (GO), and (b) of toehold-mediated strand displacement amplification. A hairpin probe 2 (HP2) containing the sgc8 aptamer was used to modify a glassy carbon electrode (GCE). Its hairpin structure is opened in the presence of PTK7 to form the PTK7-HP2 complex. The exposed part of HP2 partly hybridizes with hairpin probe 1 (HP1) that was immobilizing on the AuNPs and GO modified GCE. On addition of the hairpin probe 3 that was labeled with the redox probe Methylene Blue (MB-HP3), toehold-mediated strand displacement occurs due to complementary hybridization of HP1 with MB-HP3. This causes the release of PTK7-HP2 into the solution and makes it available for the next reaction. Under optimal conditions, PTK7 can be quantified by voltammetry (typically performed at −0.18 V) with a detection limit of 1.8 fM. The assay possesses high selectivity for PTK7 due to the employment of the aptamer. It was successfully applied to the determination of PTK7 in the debris of malignant melanoma A375 cells. Keywords Electrochemical sensor . Protein tyrosine kinase-7 . Positively charged gold nanoparticles . Negatively charged graphene oxide . Hairpin DNA probes
Introduction Protein tyrosine kinase-7 (PKT7), as one type of cell membrane proteins, is an important biomarker for a range of leukemias and solid tumors, including colon cancer, gastric cancer, lung cancer, acute myeloid leukemia (AML) [1, 2]. PTK7 also plays a role in ion regulation, energy transduction, molecular recognition and cell communication [3–5]. In addition, PTK7 is directly associated with numbers of human diseases such as colon cancer, gastric cancer and lung cancer [6–8]. Thus, sensitive and effective detection of PTK7 is of great importance in
Zongbing Li and Zhengkun Zhou contributed equally to this work. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00604-019-3849-z) contains supplementary material, which is available to authorized users. * Xiangmin Miao [email protected] 1
School of Life Science, Jiangsu Normal University, Xuzhou 221116 China
early cancer diagnosis, and to understand the dynamic role of this membrane protein in the pathogenesis of diseases. Aptamers are single-stranded DNAs or RNAs receptors obtaining in vitro by an evolution process named systematic evolution of ligands, which was constructed by exponential enrichment (SE-LEX) from larger and ramdom sequence nucleic acid libraries [9, 10].
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