Multi-parametric rigid and flexible, low-cost, disposable sensing platforms for biomedical applications

Area of Science:

• Biomedical Engineering
• Materials Science
• Analytical Chemistry

Background:

• Accurate measurement of sodium (Na+), potassium (K+), and hydrogen (H+) ions is vital in medicine, particularly for evaluating tissue ischemia.
• Conventional methods for fabricating ion-selective electrodes (ISEs) using microfabrication or printing techniques can be expensive, time-consuming, and lack standardization.

Purpose of the Study:

• To develop and evaluate novel ISEs fabricated on standardized printed circuit board (PCB) platforms.
• To assess the performance of these PCB-based ISEs for both liquid sample analysis and in-situ tissue monitoring, including integration with bioimpedance sensors for ischemia detection.

Main Methods:

• Fabrication of rigid and flexible PCB platforms equipped with multiple ISEs and a common reference electrode (RE).
• Evaluation of different PCB finishes (electroless and hard gold) for sensor performance.
• Integration of tetrapolar bioimpedance sensors for simultaneous tissue ischemia assessment.

Main Results:

• The hard gold flexible PCB platform demonstrated superior performance, achieving high sensitivities for pH, Na+, and K+ measurements.
• Sensitivities achieved were up to 73.4mV/pH, 56.3mV/log [Na+], and 57.4mV/log [K+] against custom REs.
• Simultaneous multi-analyte measurements were successfully demonstrated in test solutions and saliva samples.

Conclusions:

• Standardized PCB manufacturing offers a viable, cost-effective approach for producing high-performance ISEs.
• The developed flexible, hard gold PCB platform shows promise for disposable, multi-parametric chemical sensing diagnostic applications.
• This technology paves the way for mass-produced, low-cost diagnostic tools for medical monitoring, including tissue ischemia detection.