Sensitivity Study of Cancer Antigens (CA-125) Detection Using Interdigitated Electrodes Under Microfluidic Flow Condition

Bharath Babu Nunna1 & Debdyuti Mandal1 & Joo Un Lee2 & Shiqiang Zhuang1 & Eon Soo Lee1

BioNanoScience (2019)

# Springer Science+Business Media, LLC, part of Springer Nature 2019



The integrated module of microfluidics with the biosensor is of great research interest with the increasing trend of lab-on-the-chip

and point-of-care devices. Though there are numerous studies performed on associating the microfluidics to the biosensing

mechanisms, the study of the sensitivity variation due to microfluidic flow is very much limited. In this paper, a study of the

sensitivity variation while detecting the CA-125 antigen using interdigitated electrodes, with static drop and with microfluidic

flow of biofluid sample (CA-125 antigens with phosphate buffer saline solution), was performed. When the biofluid sample was

passed on the CA-125 antibodies that are immobilized on the gold interdigitated electrodes, the capacitance variation of the

sensing circuit was caused due to the antigenantibody interaction. However, the capacitance measured during CA-125 antigen

antibody interaction with the microfluidic flow condition (270.34 pF) was lower than static drop condition (296.09 pF) due to the

instability of the immobilized antibodies on the sensing surface that was caused by the shear stress on the sensing surface during

the microfluidic flow. This study helps to understand the capacitive sensitivity issues in the biosensing mechanisms with

microfluidic platform.

Keywords Biosensing . Microfluidics . Interdigitated electrodes . Capacitive sensing . Shear flow . Stability of biomarkers


Cite this article as: Nunna, B.B., Mandal, D., Lee, J.U. et al. BioNanoSci. (2019).