Paper Microfluidic Urine Test Device

ISEF Category: Biochemistry

Subcategory: Analytical Biochemistry  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

A paper strip can act like a tiny lab. One drop can spread through channels, react in separate zones, and turn into a color map you can measure with your phone. That means you can build a low-cost screen for glucose, protein, and pH without bulky gear. The hard part is making the colors mean the same thing every time.

What Is It?

This project uses paper as a tiny plumbing system. Microfluidic means liquid moves through very small channels. You pattern the paper so one sample splits into several paths, then each path reacts with a different chemical marker. Think of it like a fork in a trail map, where each trail ends at a different signal.

Glucose, protein, and pH matter because they give clues about sample chemistry. You are not building a medical diagnosis tool. You are testing whether a paper device can turn those clues into measurable color signals, then whether image analysis can convert color into concentration or category. Serial-dilution standards give you a known ladder to train and check the readout.

Why This Is a Good Topic

This is a strong science fair topic because you can measure real signal changes, compare designs, and test error sources without a university lab. Simulated urine keeps the work safer and more controlled, while still giving you a realistic sample matrix. The project connects to low-cost screening, point-of-care diagnostics, and field testing. You can learn calibration, image analysis, controls, and model checking in one project.

Research Questions

• How does glucose concentration change the color intensity in the glucose zone of the paper device?
• How does protein concentration change the readout in the protein zone?
• Does matching the calibration standards to simulated urine improve concentration estimates compared with water-based standards?
• To what extent does sample pH affect the accuracy of the glucose and protein measurements?
• Which image feature, RGB channel ratio, grayscale intensity, or HSV value, predicts concentration with the lowest error?
• What is the effect of paper type on signal-to-noise ratio and zone-to-zone bleed?

Basic Materials

• Chromatography paper or high-quality filter paper.
• Wax printer or wax crayons and a household iron for barrier patterning.
• Single-channel micropipettes or fixed-volume transfer pipettes.
• Microcentrifuge tubes or small sample cups.
• Glucose, protein, and pH colorimetric reagents compatible with paper tests.
• Simulated urine.
• Smartphone with manual camera controls.
• Plain white or black background box.
• Safety goggles and nitrile gloves.

Advanced Materials

• Patterned paper fabrication setup, such as a wax printer, laser cutter, or plotter.
• Calibrated micropipettes and low-retention tips.
• Flatbed scanner or multispectral camera for cross-checking image data.
• Reference glucose and albumin standards.
• Buffer solutions spanning the target pH range.
• Urine matrix additives for interference testing.
• Image analysis workstation.
• Replicate fabrication templates and punch tools.

Software & Tools

• ImageJ: Measures zone intensity and compares color signals across samples.
• Python: Fits calibration curves, checks error, and plots device performance.
• Google Sheets: Organizes standards, replicates, and quality control data.
• R: Runs statistical tests and compares model fits if you want a second analysis path.
• Jupyter Notebook: Keeps code, plots, and notes together in one place.

Experiment Steps

1. Define the measurement goal, such as estimating concentration or classifying low, medium, and high levels.
2. Choose one paper layout and one readout chemistry for each analyte, then map how the sample will split across zones.
3. Build a calibration ladder with serial-dilution standards in a matrix that matches your simulated urine.
4. Plan a fixed imaging setup and decide which color metric will become your main signal.
5. Set up controls for cross-reactivity, paper batch variation, and blank background, then decide the statistics you will use to compare designs.

Common Pitfalls

• Photographing each device under different room light, which makes the same color look like a different concentration.
• Training the calibration curve in water and then testing in simulated urine, which hides matrix effects.
• Letting one analyte zone bleed into another, which mixes signals and flattens the response.
• Using a concentration range that is too wide, which can saturate the color and ruin the middle of the curve.
• Ignoring paper batch variation, which makes two devices with the same layout give different baseline colors.

What Makes This Competitive

This becomes competitive when you treat it like a measurement study, not just a color demo. Compare multiple paper patterns, imaging metrics, and calibration strategies, then quantify which choice lowers error across the full range. Add interference tests with realistic urine matrix changes, and report confidence intervals or prediction error, not just pretty photos. A strong entry shows you can make the device repeatable, explain the failure modes, and defend why one design wins.

Project Variations

• Test artificial urine instead of a simpler buffer so you can measure matrix effects on all three analytes.
• Swap the phone camera for a flatbed scanner to compare whether capture method changes calibration stability.
• Focus on one analyte pair, such as glucose and protein, and test whether a dual-zone layout improves separation and accuracy.

Learn More

• PubMed: Search review articles on paper-based analytical devices, colorimetric biosensing, and smartphone readouts.
• NCBI Bookshelf: Look for open chapters on urinalysis, glucose testing, and protein in urine.
• Journal of Chemical Education: Find classroom-friendly papers on paper microfluidics and calibration design.
• MIT OpenCourseWare: Search analytical chemistry lectures for calibration curves, uncertainty, and assay design.
• NIH MedlinePlus: Read plain-language background on urinalysis and what glucose, protein, and pH can indicate.