Label-free electrochemical aptasensor for sensitive thrombin detection using layer-by-layer self-assembled multilayers with toluidine blue–graphene composites and gold nanoparticles

• Published in: Talanta (Oxford) Vol. 98; pp. 7 - 13
• Main Authors: Xie, Shunbi, Yuan, Ruo, Chai, Yaqin, Bai, Lijuan, Yuan, Yali, Wang, Yan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30.08.2012; Elsevier
• Subjects: Analytical chemistry; Aptamers, Nucleotide - chemistry; Carbon; Charging; Chemistry; Electrochemical aptasensor; Electrochemical methods; Electrochemical Techniques; Electrodes; Equipment Design; Exact sciences and technology; General, instrumentation; Gold; Gold - chemistry; Graphite - chemistry; Lable-free; Layer-by-layer; Limit of Detection; Metal Nanoparticles - chemistry; Multilayers; Nanocomposites; Nanocomposites - chemistry; Nanomaterials; Nanostructure; Oxidation-Reduction; Reproducibility of Results; Static Electricity; Thrombin; Thrombin - analysis; Tolonium Chloride - chemistry; Lable-free; Thrombin; Electrochemical aptasensor; Layer-by-layer; Self-assembled layer; Electrochemical method; Nanoparticle; Immobilization; Barrier; Selectivity; Chemical enrichment; Design; Target; Signal; Thrombin(drug); Detection limit; Nanocomposite; Gold; Toluidine blue; Multilayer; Carbon electrode; Chemical sensor; Protein; Thiazine dye; Adsorption; Transfer; Detection
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2012.06.019

In the present study, toluidine blue–graphene (Tb–Gra) nanocomposites were prepared to design a Lable-free electrochemical aptasensor for highly sensitive detection of thrombin based on layer-by-layer (LBL) technology. The nanocomposites with excellent redox electrochemical activities were first immobilized on the gold nanoparticles (nano-Au) modified glassy carbon electrodes (GCE). Then, the LBL structure was performed by electrostatic adsorption between the positively charged Tb–Gra and negatively charged nano-Au, which formed {Tb–Gra/nano-Au}n multilayer films for electroactive species enrichment and biomolecule immobilization. Subsequently, the thiolated thrombin binding aptamer (TBA) was assembled on the nano-Au surface through Au–S bond. In the presence of target thrombin (TB), the TBA on the multilayer could catch the thrombin onto the electrode surface, which resulted in a barrier for electro-transfer, leading to the decrease of the electrochemical signal of Tb–Gra nanocomposites. Under the optimal conditions, a wide detection range from 0.001nM to 80nM and a low detection limit of 0.33 pM (defined as S/N=3) for thrombin were obtained. In addition, the sensor exhibited excellent selectivity against other proteins. ► The aptasensors exhibited low detection limit and wide linear range to thrombin. ► The Tb–Gra nanocomposites combined the advantages of graphene and toluidine blue. ► The aptasensors showed good fabrication reproducibility and sufficient stability.