A label-free immunosensor for diagnosis of Dengue infection with simple electrical measurements.
The interdigitated electrodes and electrical measurements for the diagnosis of dengue infection using antigen-antibody conjugation method are reported. As a proof of concept, pre-inactivated dengue virus was firstly immobilized indirectly onto the immunosensor surface, pre-coated with sol-gel derived barium strontium titanate (BST) thin film and modified with organic self-assembled monolayer (SAM) formed by 3-aminopropyltriethoxysilane (APTS) and a cross-linker glutaraldehyde over the interdigitated electrodes. The modified sensor surface served as selective sensing probe to capture/conjugate the dengue antibody molecules present in patient's serum. Our immunosensor is based on non-faradaic process, using only de-ionized water as electrolyte during the simple electrical measurements. Both ac impedance spectroscopy and dc I-V measurements between the electrodes gave a clearly discernable and repeatable signal to positively identify the presence of dengue antibody in the serum. Direct correlation was obtained between the signal outputs with respect to antibody concentrations. The measured signal changes in impedance/current without/with the presence of dengue antibody were attributed to the surface conductivity change upon biomolecules immobilization and the dipole-induced interfacial polarization potential at the SAM film/biomolecules interface. By monitoring the impedance or current change, the antibody molecules in the patient's serum could be positively detected.
School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore.
Xiaoqin
X
Fang
Ooi Kiang
OK
Tan
Man Siu
MS
Tse
Eng Eong
EE
Ooi
D000956:Antigens, Viral / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003715:Dengue / Q000175:diagnosis* / Q000821:virology*; D003716:Dengue Virus / Q000276:immunology*; D004563:Electrochemistry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling
D000956:Antigens, Viral