A label-free impedimetric DNA sensing chip integrated with AC electroosmotic stirring

• Published in: Biosensors & bioelectronics Vol. 43; pp. 348 - 354
• Main Authors: Wu, Ching-Chou, Yang, Dong-Jie
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.05.2013; Elsevier
• Subjects: AC electroosmosis; Biological and medical sciences; Biosensing Techniques - instrumentation; Biotechnology; Dielectric Spectroscopy - instrumentation; DNA - analysis; DNA - genetics; DNA sensor; Electrochemical impedance spectroscopy; Equipment Design; Equipment Failure Analysis; Fundamental and applied biological sciences. Psychology; Label-free; Microfluidics - instrumentation; Oligonucleotide Array Sequence Analysis - instrumentation; Staining and Labeling; Systems Integration; AC electroosmosis; Label-free; DNA sensor; Electrochemical impedance spectroscopy; Detector; DNA; Electroosmosis; DNA chip
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2012.12.041

AC electroosmosis (ACEO) flow and label-free electrochemical impedance spectroscopy are employed to increase the hybridization rate and specifically detect target DNA (tDNA) concentrations. A low-ionic-strength solution, 6.1μS/cm 1mM Tris (pH 9.3), was used to produce ACEO and proved the feasibility of hybridization. Adequate voltage parameters for the simultaneous ACEO driving and DNA hybridization in the 1mM Tris solution were 1.5 Vpp and 200Hz. Moreover, an electrode set with a 1:4 ring width-to-disk diameter ratio exhibited a larger ACEO velocity above the disk electrode surface to improve collecting efficiency. The ACEO-integrated DNA sensing chips could reach 90% saturation hybridization within 117s. The linear range and detection limit of the sensors was 10aM–10pM and 10aM, respectively. The label-free impedimetric DNA sensing chips with integrated ACEO stirring can perform rapid hybridization and highly-sensitive detections to specifically measure tDNA concentrations. ► We developalabel-free impedimetric DNA biosensor integrated with ACEO stirring. ► 1mM Tris can compromise the electrolyte requirements for DNA hybridization and ACEO stirring. ► Under ACEO stirring of 1.5 Vpp and 200Hz, 90% saturation hybridization is achieved within 117s. ► The hybridization is estimated by the change in electron transfer resistance in 10mM TES (pH 7.0). ► The linear range and detection limit of the sensing chips is 10am–10pm and 10am, respectively.