Determination of ionic concentration in microfluidics using electrical methods

Determination of ionic concentration in microfluidics using electrical methods

WoS Article

Microfluidic systems are essential in various scientific and engineering applications, especially in biochemical analysis, medical diagnostics, and pharmaceutical research. Accurate monitoring and control of ionic concentration within these systems are essential for achieving high efficiency and specificity in their applications. This study investigates using van der Pauw (vdP) structures and 4-probe line methods, adapted from semiconductor technology, to measure ionic concentrations in microfluidic channels. These methods offer precise, real-time monitoring without requiring additional fabrication steps or specialized electrode materials. We fabricated microfluidic chips with dual deep reactive ion etching and anodic bonding. These chips, integrated into an automated system, were tested for KCl concentrations (0.1–4 M) across various channel depths (9.55 ± 0.23) µm, (22.37 ± 0.41) µm, and (82.26 ± 1.56) µm. Electrical measurements showed the vdP method provides higher accuracy and lower standard deviation than the 4-probe line method. Our findings demonstrate the potential for integrating vdP structures into complex microfluidic systems for precise, real-time monitoring of ionic concentrations, enhancing the functionality and reliability of microfluidic devices.

Microfluidic systems are essential in various scientific and engineering applications, especially in biochemical analysis, medical diagnostics, and pharmaceutical research. Accurate monitoring and control of ionic concentration within these systems are essential for achieving high efficiency and specificity in their applications. This study investigates using van der Pauw (vdP) structures and 4-probe line methods, adapted from semiconductor technology, to measure ionic concentrations in microfluidic channels. These methods offer precise, real-time monitoring without requiring additional fabrication steps or specialized electrode materials. We fabricated microfluidic chips with dual deep reactive ion etching and anodic bonding. These chips, integrated into an automated system, were tested for KCl concentrations (0.1–4 M) across various channel depths (9.55 ± 0.23) µm, (22.37 ± 0.41) µm, and (82.26 ± 1.56) µm. Electrical measurements showed the vdP method provides higher accuracy and lower standard deviation than the 4-probe line method. Our findings demonstrate the potential for integrating vdP structures into complex microfluidic systems for precise, real-time monitoring of ionic concentrations, enhancing the functionality and reliability of microfluidic devices.

Microfluidics; Van der Pauw structure; Four-probe method; Ionic concentration; Electrical measurement; Microfluidic chip fabrication

Microfluidics; Van der Pauw structure; Four-probe method; Ionic concentration; Electrical measurement; Microfluidic chip fabrication

BRODSKÝ, J.; LIU, X.; JARUŠEK, J.; MIGLIACCIO, L.; NEUŽIL, P.; ZÍTKA, O.; GABLECH, I.

01.10.2025

ELSEVIER SCIENCE SA

SWITZERLAND, LAUSANNE

0924-4247

SENSORS AND ACTUATORS A-PHYSICAL

392

10

Swiss Confederation

1

6

6

https://www.sciencedirect.com/science/article/pii/S0165993624005983?via=ihub