Synergistic optical enhancement of Au/AgNTs@CDs immunoprobe with tips and gaps for SERS/FL dual mode detection of PSA

Robust and highly sensitive nano-optical immunoprobes have emerged as powerful tools to improve the accuracy and sensitivity of early disease diagnosis. This work develops a pentagonal gold/silver nanotube @ carbon dot (Au/AgNTs@CDs) SERS/FL dual-mode immunoprobe for detecting prostate-specific antigen (PSA) in serum by subtly integrating small gaps and branch tip structures. Benefiting from the synergistic optical enhancement of tips and small gaps, this novel rough porous Au/Ag nanotube exhibits larger specific surface area and more active sites as well as remarkable stability. The optical enhancement brought by the innovative structural design increases the detection sensitivity of the immunoprobe to the state of the art. To the best of our knowledge, the limit of detection is an order of magnitude lower than reported in the literature in SERS and fluorescence modes, respectively. Furthermore, both modes exhibit excellent robustness and specificity. Therefore, the design of this immunoprobe provides a new perspective and broad application prospects for improving the sensitivity and accuracy of clinical diagnosis.