title: A repeatable assembling and disassembling electrochemical aptamer cytosensor for ultrasensitive and highly selective detection of human liver cancer cells.
abstract: In this work, a repeatable assembling and disassembling electrochemical aptamer cytosensor was proposed for the sensitive detection of human liver hepatocellular carcinoma cells (HepG2) based on a dual recognition and signal amplification strategy. A high-affinity thiolated TLS11a aptamer, covalently attached to a gold electrode through Au-thiol interactions, was adopted to recognize and capture the target HepG2 cells. Meanwhile, the G-quadruplex/hemin/aptamer and horseradish peroxidase (HRP) modified gold nanoparticles (G-quadruplex/hemin/aptamer-AuNPs-HRP) nanoprobe was designed. It could be used for electrochemical cytosensing with specific recognition and enzymatic signal amplification of HRP and G-quadruplex/hemin HRP-mimicking DNAzyme. With the nanoprobes as recognizing probes, the HepG2 cancer cells were captured to fabricate an aptamer-cell-nanoprobes sandwich-like superstructure on a gold electrode surface. The proposed electrochemical cytosensor delivered a wide detection range from 1×10(2) to 1×10(7) cells mL(-1) and high sensitivity with a low detection limit of 30 cells mL(-1). Furthermore, after the electrochemical detection, the activation potential of -0.9 to -1.7V was performed to break Au-thiol bond and regenerate a bare gold electrode surface, while maintaining the good characteristic of being used repeatedly. The changes of gold electrode behavior after assembling and desorption processes were investigated by electrochemical impedance spectroscopy and cyclic voltammetry techniques. These results indicate that the cytosensor has great potential in disease diagnostic of cancers and opens new insight into the reusable gold electrode with repeatable assembling and disassembling in the electrochemical sensing.
authors.affiliation: School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China.
authors.forename: Duanping
authors.initials: D
authors.lastname: Sun
authors.affiliation: School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Lu
authors.affiliation: School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China. Electronic address: chenzg@mail.sysu.edu.cn.
authors.forename: Zuanguang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Chemistry, Faculty of Science, The University of Hong Kong, Hong Kong, China.
authors.forename: Manni
authors.initials: M
authors.lastname: Mo
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D006046:Gold / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology; D053768:Metal Nanoparticles / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D052157:Aptamers, Nucleotide; D013438:Sulfhydryl Compounds; D006046:Gold
keywords: Aptamer; Electrochemical cytosensor; HepG2; Repeatable assembling and disassembling; Reusable gold electrode