Development of FL/MR dual-modal Au nanobipyramids for targeted cancer imaging and photothermal therapy.

Multifunctional nanodrugs have emerged as an effective platform to integrate multiple imaging and therapeutic functions for tremendous biomedical applications. However, the development of a simple potent theranostic nanoplatform is still an intractable challenge. Herein, a novel theranostic nanoplatform was developed by coupling prepared Au nanobipyramids with Gd ₂ O ₃ , Au nanoclusters and denatured bovine serum albumin (AuNBP-Gd ₂ O ₃ /Au-dBSA) for FL/MR dual-modal imaging guided photothermal therapy. AS1411 aptamers were conjugated to enhance its targetability towards breast cancer. The AS1411-AuNBP-Gd ₂ O ₃ /Au-dBSA suspension could be readily heated above 40 °C at a low concentration (2 mg/L) and NIR density (1 W/cm ² ). The AS1411-AuNBP-Gd ₂ O ₃ /Au-dBSA revealed a fluorescence quantum yield of 4.2% and higher longitudinal relaxivity rate of 6.75 mM ^-1  s ^-1 compared to Gd-DTPA of 4.45 mM ^-1  s ^-1 . As a result, the AS1411-AuNBP-Gd ₂ O ₃ /Au-dBSA functions as a multimodal nanoprobe of photothermal, fluorescence and MR imaging for specific tumor diagnosis and guidance of therapy, which was validated via in vitro and in vivo tests. Moreover, AS1411-AuNBP-Gd ₂ O ₃ /Au-dBSA nanoparticles indicated excellent photothermal anticancer effect more than 95% in both in vitro and in vivo tests. Besides, the low toxicity of AS1411-AuNBP-Gd ₂ O ₃ /Au-dBSA nanocomposites was further confirmed in vitro and in vivo. Thus, these results demonstrated the AS1411-AuNBP-Gd ₂ O ₃ /Au-dBSA nanocomposites as a rational design of multifunctional nanoplatform to enable multimodal imaging guided photothermal therapy.
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