Smartphone Magnetometers: Empowering Portable Diagnostics with Magnetized Hydrogels

Smartphone Magnetometers: Empowering Portable Diagnostics with Magnetized Hydrogels

Researchers at the National Institute of Standards and Technology (NIST) have devised a novel technique for measuring glucose levels and other biomarkers with surprising accuracy. The method harnesses the power of smartphone magnetometers and magnetised hydrogels.

This discovery opens up new possibilities for portable diagnostics, which hopefully will be another way of making healthcare more accessible and affordable.

Magnetometers are built into nearly every modern smartphone and are primarily used to detect the Earth’s magnetic field and provide navigation information. However, the NIST researchers have found a way to repurpose these magnetometers to measure the concentration of various compounds in liquid samples. By leveraging the sensitivity of these magnetometers, this technique offers a cost-effective and readily available solution for diagnostic testing.

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The new technique relies on magnetised hydrogels—porous materials that swell or contract in response to specific stimuli, such as glucose or changes in pH levels. The NIST team embedded magnetic particles within these hydrogels, creating a unique composite material that moves the particles closer to or farther from the smartphone’s magnetometer as the hydrogel expands or shrinks. This movement causes detectable changes in the magnetic field strength, allowing for quantitative measurements of the target analyte.

To demonstrate the effectiveness of their technique, the researchers conducted a proof-of-concept study focusing on measuring glucose and pH levels. They attached a tiny well containing the test solution and a strip of the magnetised hydrogel to a smartphone. As the hydrogel responded to glucose or pH changes, the magnetic particles moved accordingly, triggering measurable changes in the magnetic field detected by the smartphone’s magnetometer.

The results were impressive, with the system achieving glucose concentration measurements as low as a few millionths of a mole—a sensitivity level that could enable routine glucose testing using saliva instead of blood. Furthermore, the study suggests that smartphone magnetometers can measure pH levels with the same accuracy as expensive benchtop meters but at a fraction of the cost.

The implications of this discovery extend beyond glucose monitoring and pH measurement. By tailoring magnetised hydrogels to react to various compounds, this technology could be adapted for a wide range of applications in healthcare and environmental monitoring. For example, it could enable the detection of DNA strands, specific proteins, and histamines at deficient concentrations, opening up new possibilities for disease diagnosis and monitoring.

However, the technology is in its infancy, and several challenges must be addressed to make this technique commercially viable. These include developing methods for mass-producing the hydrogel test strips, ensuring their long shelf life, and optimising their response time. Additionally, further research is needed to improve the measurements’ accuracy and sensitivity, potentially enabling the detection of analytes at nanomolar concentrations.

Developing a smartphone-based diagnostic tool using magnetometers and magnetised hydrogels represents a significant step in making healthcare more accessible and affordable. This technology could revolutionise point-of-care testing and environmental monitoring by leveraging smartphones’ ubiquity and the versatility of new intelligent materials. As researchers continue to refine and optimise this technique, we look forward to a future where portable, low-cost diagnostic tools become an integral part of our healthcare system.

TLDR (Too Long; Didn’t Read):

  • NIST researchers developed a technique using smartphone magnetometers and magnetised hydrogels to accurately measure glucose levels and other biomarkers.
  • Magnetised hydrogels embedded with magnetic particles swell or contract in response to specific stimuli, causing detectable changes in the magnetic field.
  • A proof-of-concept study demonstrated the system’s ability to measure glucose and pH levels with high sensitivity and accuracy.
  • This technology has potential applications in healthcare, disease diagnosis, and environmental monitoring.
  • Future developments include the mass production of hydrogel test strips and optimising response time and accuracy.
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