Bioconjugation of Gold Nanobipyramids for SERS Detection and Targeted Photothermal Therapy in Breast Cancer

Gold nanobipyramids (Au NBPs) with two sharp tips present an extremely strong electric field enhancement, which endows them with more advantages in biomedical photonics than other gold nanostructures. The application of Au NBPs for diagnosis and therapy is now under intensive investigation. Here, we report Au NBPs for surface-enhanced Raman scattering (SERS) detection and photothermal therapy (PTT)' of MCF-7 cancer cells both in vitro and in vivo via bioconjugation with Raman reporter 2-naphthalenethiol (2-NAP) and folic acid (FA). The results showed that bioconjugated Au NBPs not only could be used for the quantitative detection of the MCF-7 cells in the range of 5-500 cells/mL, but also lead to the enhanced Raman signal in MCF-7 tumor-bearing nude mice with high specificity. Moreover the bioconjugated Au NBPs exhibited excellent photothermal performance in both in vitro and in vivo therapies, in which the cell viability decreased to 6.44% and the relative volume of MCF-7 tumors treated with bioconjugated Au NBPs reduced to 0.037 under the irradiation of an 808 nm laser. Our results indicate that bioconjugated Au NBPs offer an excellent nanoplatform for PTT and SERS detection in the future.