Fluorescence-infrared absorption dual-mode nanoprobes based on carbon dots@SiO2 nanorods for ultrasensitive and reliable detection of carcinoembryonic antigen

The level of carcinoembryonic antigen (CEA) in serum has the significant reference value for early diagnosis and treatment of various cancers. However, the CEA detection still suffers from the issue of limited sensitivity and reliability. Herein, a fluorescence (FL)-infrared absorption (IRA) dual-mode nanoprobe was fabricated based on carbon dots (CDs)@SiO2 nanorod for CEA detection. The FL and IRA signals display no mutual interference and can verify each other, ensuring the reliability of assay results. The highly sensitive FL signal originating from the CDs is enhanced by the surface passivation of SiO2 and improves the overall sensitivity of the detection. The detection range spans 9 orders of magnitude and the limit of detection reaches 794.6 ag mL−1, which are great superior to the commercial kits and most of the previous reports. Satisfactory recovery over the commercial kits was achieved in real serum samples. The ultrasensitive and reliable FL-IRA detection strategy sheds light on a new avenue toward promoting the practicability of the nanoprobes in clinical cancer diagnosis. [Display omitted] •An ultrasensitive and reliable dual-mode immunosensor was proposed.•Carbon dots@SiO2 nanorods were fabricated as fluorescence-infrared absorption nanoprobes.•Detection sensitivity reached 794.6 ag mL−1.•The detection results of blood samples proved the practicability of the dual-mode nanoprobes.