Integrated immunochromatographic strip with glucometer readout for rapid quantification of phosphorylated proteins

A new technology to quantify phospho-p53¹⁵ by converting its content to the amount of glucose which is detectable by a glucometer was developed. An immunochromatographic test strip (ITS) was used as a disposable platform, where primary antibody (Ab₁)-modified Fe₃O₄ magnetic nanoparticles (Fe₃O₄-Ab₁) were settled on the test zone to capture both the target phospho-p53¹⁵ and the detection antibody (Ab₂)-glucose encapsulating liposome (GEL) conjugate. The measurement was based on the release and subsequent detection of glucose from Ab₂-GEL using a glucose meter (GM). The amount of glucose is proportional to the phospho-p53¹⁵ concentration from 0.1 to 50 ng mL^-1, the limit of detection is 50 pg mL^-1 (3S/N). The high sensitivity was a result of the huge number of glucose encapsulated in the liposome. Taking the advantage of low cost, widespread availability and portability of the test trip, together with the personal GM, the presented approach can be easily used to detect other disease biomarkers in medical diagnostics and environmental monitoring.