Sensors (Dec 2023)

Label-Free, Impedance-Based Biosensor for Kidney Disease Biomarker Uromodulin

  • Kunj Vora,
  • Norbert Kordas,
  • Karsten Seidl

DOI
https://doi.org/10.3390/s23249696
Journal volume & issue
Vol. 23, no. 24
p. 9696

Abstract

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We demonstrate the development of a label-free, impedance-based biosensor by using a passivation layer of 50-nm tantalum pentoxide (Ta2O5) on interdigitated electrodes (IDE). This layer was fabricated by atomic layer deposition (ALD) and has a high dielectric constant (high-κ), which improves the capacitive property of the IDE. We validate the biosensor’s performance by measuring uromodulin, a urine biomarker for kidney tubular damage, from artificial urine samples. The passivation layer is functionalized with uromodulin antibodies for selective binding. The passivated IDE enables the non-faradaic impedance measurement of uromodulin concentrations with a measurement range from 0.5 ng/mL to 8 ng/mL and with a relative change in impedance of 15 % per ng/mL at a frequency of 150 Hz (log scale). This work presents a concept for point-of-care biosensing applications for disease biomarkers.

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