Aptamer-based sensors selectively detect and measure a wide variety of molecules. When the target molecule is present, it binds to a specifically designed aptamer probe which creates a measurable electrochemical signal. Due to their specificity and selectivity, these sensors are useful for medical and environmental testing applications. However, complicated signal analysis methods make running tests with this promising technology too complicated for point-of-use applications.
To enable more simple analysis, aptamer-based sensors have been developed that change color in response to electrical signal. In these sensors, metal nanoparticle aggregation within the sample itself is what produces a color change, meaning metal particles must be added to the sample before testing. Sample dilution and pretreatment are also required. Also, because color change takes place within the sample, the sample can interfere with detection and compromise accuracy.
Dr. Ryan White, professor for the Department of Chemistry at the University of Cincinnati and Ohio Eminent Scholar, and his team have developed a new electrochemical aptamer-based sensor with a fast, easy to detect, and accurate color change. The sample sensing component is de-coupled from the color changing component, so any volume of the sample can be tested directly without any modification. The color change rate is prominent and fast enough that analyte concentration can be both detected with the human eye and quantitatively measured with user-friendly smartphone-based algorithms in under two minutes.