Bharath Babu Nunna1, Debdyuti Mandal1, Joo Un Lee2, Harsimranjit Singh1, Shiqiang Zhuang1, Durgamadhab Misra3, Md Nasir Uddin Bhuyian3 and Eon Soo Lee1*
Nano Convergence 6, 3 (2019)
https://doi.org/10.1186/s40580-019-0173-6
Abstract:
Integrating microfluidics with biosensors is of great research interest with the increasing trend of lab-on-the chip and
point-of-care devices. Though there have been numerous studies performed relating microfluidics to the biosensing
mechanisms, the study of the sensitivity variation due to microfluidic flow is very much limited. In this paper, the sensitivity…
of interdigitated electrodes was evaluated at the static drop condition and the microfluidic flow condition. In
addition, this study demonstrates the use of gold nanoparticles to enhance the sensor signal response and provides
experimental results of the capacitance difference during cancer antigen-125 (CA-125) antigen–antibody conjugation
at multiple concentrations of CA-125 antigens. The experimental results also provide evidence of disease-specific
detection of CA-125 antigen at multiple concentrations with the increase in capacitive signal response proportional
to the concentration of the CA-125 antigens. The capacitive signal response of antigen–antibody conjugation on
interdigitate electrodes has been enhanced by approximately 2.8 times (from 260.80 to 736.33 pF at 20 kHz frequency)
in static drop condition and approximately 2.5 times (from 205.85 to 518.48 pF at 20 kHz frequency) in
microfluidic flow condition with gold nanoparticle-coating. The capacitive signal response is observed to decrease at
microfluidic flow condition at both plain interdigitated electrodes (from 260.80 to 205.85 pF at 20 kHz frequency) and
gold nano particle coated interdigitated electrodes (from 736.33 to 518.48 pF at 20 kHz frequency), due to the strong
shear effect compared to static drop condition. However, the microfluidic channel in the biosensor has the potential
to increase the signal to noise ratio due to plasma separation from the whole blood and lead to the increase concentration
of the biomarkers in the blood volume for sensing.
Keywords: Biosensor, Interdigitated gold electrodes, Microfluidic channel, Gold nanoparticles, Capacitance
measurements