A multicolor immunosensor for point-of-care testing NTRK1 gene fusion

•A multicolor immunosensor was fabricated for point-of-care testingof NTRK1 gene fusion marker-TRKA protein.•The TRKA protein was semi-quantitative detection based on the etching of Au NBPs within 20 min by the naked eyes.•TRKA protein in human serum was tested successfully with good accuracy and precision. The gene fusion of Neurotrophic tropomyosin receptor kinase (NTRK) promotes the formation of tumors and is closely related to multiple cancers. Therefore, the detection of NTRK gene fusion markers has been a research hotspot in recent years. However, up to now, there is still lack of a fast and effective detection method for point-of-care testing (POCT). Herein, a multicolor immunosensor for point-of-care testing NTRK1 gene fusion by the naked eye was fabricated. Au nanobipyramids (Au NBPs) can be etched by 3, 3′, 5, 5′-tetramethylbenzidine ions (TMB2+) to produce a variety of aspect ratios, and the blue shift of its longitudinal plasmon band showed different color changes. So, the Au NBPs were combined with horseradish peroxidase (HRP)-TMB immunoassay system for achieving qualitative and semi-quantitative detection of NTRK1 gene fusion marker within 20 min by the naked eyes. The results shows that the relevant linear range for detection of TRKA protein was 7.5 pg/mL to 240 pg/mL. The constructed immunosensor will be expected to be used to quickly detect NTRK gene fusion markers in remote areas with underdeveloped medical conditions.