Interdigitated Sensor Optimization for Blood Sample Analysis.

Area of Science:

• Electrical Engineering
• Biomedical Engineering
• Materials Science

Background:

• Interdigitated (ITD) sensors are crucial for micro-volume bioimpedance analysis (BIA).
• Electrode size in ITD sensors can limit impedance measurement bandwidths due to the double-layer effect.
• Optimizing sensor geometry is key for effective BIA of biological samples.

Purpose of the Study:

• To optimize the frequency band of interdigitated (ITD) sensors for bioimpedance analysis (BIA).
• To investigate the impact of the metalization ratio (α) on ITD sensor performance.
• To enhance the extraction of intrinsic electrical properties from low-volume biological samples.

Main Methods:

• Development of an electrical sensor model to study the metalization ratio (α).
• Simulation and theoretical analysis to determine the optimal α for frequency band improvement.
• Experimental validation using three ITD sensors and blood sample measurements.

Main Results:

• An optimal metalization ratio (α) of 0.6 was identified.
• This ratio improved the low-frequency cutoff by a factor of up to 2.5.
• The optimized sensor successfully extracted intrinsic electrical properties of blood within the target frequency band.

Conclusions:

• The metalization ratio (α) is a critical parameter for optimizing ITD sensor performance in BIA.
• A ratio of 0.6 enhances the usable frequency range for analyzing micro-scale biological samples.
• Optimized ITD sensors provide a reliable method for characterizing the electrical properties of biological fluids.