Electrical detection of DNA hybridization: three extraction techniques based on interdigitated Al/Al2O3 capacitors.

Research Center on Micro and Nanoscopic Materials and Electronic Devices, Belgium.
Biosensors & Bioelectronics (Impact Factor: 6.45). 05/2007; 22(9-10):2199-207. DOI: 10.1016/j.bios.2006.10.024
Source: PubMed

ABSTRACT Based on interdigitated aluminum electrodes covered with Al(2)O(3) and silver precipitation via biotin-antibody coupled gold nano-labels as signal enhancement, three complementary electrical methods were used and compared to detect the hybridization of target DNA for concentrations down to the 50 pM of a PCR product from cytochrome P450 2b2 gene. Human hepatic cytochrome P450 (CYP) enzymes participate in detoxification metabolism of xenobiotics. Therefore, determination of mutational status of P450 gene in a patient could have a significant impact on the choice of a medical treatment. Our three electrical extraction procedures are performed on the same interdigitated capacitive sensor lying on a passivated silicon substrate and consist in the measurement of respectively the low-frequency inter-electrodes capacitance, the high-frequency self-resonance frequency, and the equivalent MOS capacitance between the short-circuited electrodes and the backside metallization of the silicon substrate. This study is the first of its kind as it opens the way for correlation studies and noise reduction techniques based on multiple electrical measurements of the same DNA hybridization event with a single sensor.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Coiled-coil peptide (CCP) modified microelectrode array with comb structure (MACS) has been utilized to fabricate an electrochemical biosensor for antibody detection. Thiol terminated CCP has been employed for self-assembling on MACS and peptide chains connecting amino acid sequence 98-106 (YPYDVPDYA) of human Influenza virus hemagglutinin (HA) has been used as a molecular receptor for HA-antibody. Electrochemical impedance (EIS) studies, cyclic voltammetry studies, atomic force microscopic imaging and contact angle measurements were utilized to characterize self-assembly of CCP on MACS surface. Further, EIS studies were used to investigate interaction between CCP and HA-antibody at different concentrations. EIS measurements revealed that the specific interaction of HA-antibody with CCP gives rise to a clear increase in the value of interfacial charge transfer resistance (Rct). A linear relationship between Rct and the logarithm of HA-antibody concentration was found for the concentration range of 1 pg ml−1 to 100 ng ml−1, with a detection limit of 1 pg ml−1. Negligible change of Rct was observed by incubating the sensor in solutions of other proteins such DO1, anti-GFAP, anti-IL6 and BSA, suggesting high selectivity of descried immunosensor for HA-antibody. These results demonstrated that the CCP modified MACS based platform can provide a versatile matrix for sensitive detection of desired target.
    Sensors and Actuators B Chemical 04/2014; 194:127–133. · 3.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A capacitive biosensor based on an interdigitated electrode (IDE) with nanoislands was developed for label-free detection of antigen-antibody interactions. To enable sensitive capacitive detection of protein adsorption, the nanoislands were fabricated between finger electrodes of the IDE. The effect of the nanoislands on the sensitive capacitive measurement was estimated using horseradish peroxidase (HRP) as a model protein. Additionally, a parylene-A film was coated on the IDE with nanoislands to improve the efficiency of protein immobilization. By using HRP and hepatitis B virus surface antigen (HBsAg) as model analytes, the effect of the parylene-A film on the capacitive detection of protein adsorption was demonstrated.
    Analytica Chimica Acta. 01/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: The glass-based LTPS (low temperature polysilicon) TFT (thin-film transistor) process, as widely known for making liquid crystal displays, is utilized for the first time to make CMOS capacitive sensors for dopamine detection. Dopamine plays important roles in human behavior, cognition, and motor activity. The interface capacitance change, after its binding with 4- carboxyphenylboronic acid (CPBA), was detected by interdigitated microelectrodes and integrated sensing circuits. Three sensor designs showed measured sensitivities of -3.9 fF/mM, -5.4 fF/mM, and -7.2 fF/mM, respectively. The minimum detectable capacitance changes were 12.7 aF, 14.7 aF, and 13.5 aF, equivalent to detectable dopamine concentrations of 3.2 PM, 2.7 PM, and 1.9 PM, respectively. I. INTRODUCTION

Full-text (2 Sources)

Available from
Jun 3, 2014