| Ultrasensitive and quantitative fast screening of cancer biomarkers by immunochromatography test strip(ICTS)is still challenging in clinic.The gold NPs based ICTS with colorimetric readout enables a quick spectrum screening but suffers from nonquantitative performance;although ICTS with fluorescence readout(FICTS)allows quantitative detection,its sensitivity still deserves more efforts and attentions.In this work,by taking advantages of colorimetric ICTS and FICTS,we described a reverse fluorescence enhancement ICTS(rFICTS)with bimodal signal readout for ultrasensitive and quantitative fast screening of carcinoembryonic antigen(CEA).First,we synthesized the gold nanoparticles,and through electrostatic adsorption to form colloidal gold probe with the labeled antibody.Then,ues colloidal gold probe as a signal markers,we prepared the colloidal gold immune chromatography test paper,and optimize its performance.After that,the fluorescent probe was prepared with fluorescein Cy5 and antibody through amide reaction,and the rFICTS was prepared and got a comprehensive evaluation of its quality.In the end,CEA as templates,120 cases of clinical patients serum were diagnosed through the dual-modal test with the rFICTS.In the presence of target,AuNPs aggregation in T line induced colorimetric readout,allowing on-the-spot spectrum screening in 10 min by naked eye.Meanwhile,the reverse fluorescence enhancement signal enabled more accurately quantitative detection with better sensitivity(5.89 pg/mL for CEA),which is more than 2 orders of magnitude lower than that of the conventional FICTS.The accuracy and stability of the rFICTS were investigated with more than 120 clinical serum samples for large-scale screening.Results were accurate and reliable,and the dual-modal test were fast and accurate.These results indicated this rFICTS is particularly suitable for point-of-care(POC)diagnostics in both family and communities,and build a new type of rapid vitro detection. |
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