Peroxide test strip (PTS) has been widely used for the point-of-care testing (POCT), but its poor sensitivity is a big obstacle for analyzing trace target. Herein, a triple signal amplifying platform integrating the liposome enrichment, the hybridization chain reaction (HCR) circuit, and the image analysis method was constructed to enhance the visual readout of PTS for the sensitive detection of adenosine triphosphate (ATP), an important biomarker of food spoilage. In the presence of ATP, the HCR amplifier was firstly initiated on the surface of magnetic beads (MBs), inducing a large number of glucose oxidase (GOD) imbedded liposomes to be attached. After the magnetic separation, the linked liposomes were destroyed and the enriched GOD was released to react with glucose to produce H2O2, which can enhance the color change of PTS. Finally, an image analysis method was developed to further amplify the colorimetric difference of human visual perception of PTS readout. This triple signal amplification strategy was used to detect ATP in the linear range from 50 to 250 nmol/L, and the limit of detection (LOD, 3σ/k) was 0.65 nmol/L. Finally, this method has been successfully applied for accurate and sensitive detection of ATP in watermelon juice, showing its great potential for quick determining whether food is spoiled.
Keywords: Adenosine triphosphate; Point-of-care testing; Signal amplification; Test strip.
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