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Millifluidic ion-selective optodes with integrated optical detection for colorimetric quantification of urinary
Yonghao Li1, Rebecca Goodhart1, Aishwarya Patel1
1Department of Chemistry, Virginia Commonwealth University, 1001 W. Main Street, Richmond, VA, 23284, USA.
Talanta
|January 10, 2026
Summary
A new low-cost colorimetric sensor enables at-home urinary calcium testing. This user-friendly device accurately measures calcium levels, aiding in diagnosing metabolic disorders like kidney stones and parathyroid conditions.
Area of Science:
- Analytical Chemistry
- Biomedical Engineering
- Clinical Diagnostics
Background:
- Urinary calcium measurement is crucial for diagnosing calcium metabolism disorders.
- Current testing requires clinical visits, lacking convenient at-home options.
- Accurate urinary calcium quantification is vital for conditions like kidney stones and parathyroid diseases.
Purpose of the Study:
- To develop a low-cost, user-friendly colorimetric sensor for quantitative urinary calcium measurement.
- To enable at-home or point-of-care testing for urinary calcium.
- To provide a reliable method for diagnosing hypercalciuria and hypocalciuria.
Main Methods:
- A millifluidic sensor using a sensing oil with hydrophobic chemicals (chromoionophore, ion exchanger, ionophore) was developed.
- The sensor was integrated with a custom-built absorbance detector (LED and photodetector).
- The sensor quantified calcium ions by measuring absorbance changes in the sensing oil after urine extraction.
Main Results:
- The sensor demonstrated a linear response for 0-10 mM calcium ions.
- Measurements from five urine samples showed good agreement with reference methods.
- Recovery rates for spiked samples ranged from 94% to 103%, indicating high reliability.
Conclusions:
- The developed colorimetric sensor offers a low-cost (<20¢ per test) and user-friendly method for urinary calcium testing.
- The system, including the detector (<$50), is suitable for resource-limited settings, including home use and clinics.
- This technology holds significant promise for improving the accessibility and convenience of diagnosing calcium metabolism disorders.
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