BSA-Coated Gold Nanorods for NIR-II Photothermal Therapy.

The second near infrared window is considered to be the optimal optical window for medical imaging and therapy as its capability of deep tissue penetration. The preparation of the gold nanorods with long wavelength absorption and low cytotoxicity is still a challenge. A series gold nanorods with large aspect ratio have been synthesized. Strong plasma absorption in the second near infrared window from 1000 to 1300 nm could be observed. The biocompatibility of the synthesized gold nanorods is dramatically improved via coating by bovine serum albumin (BSA), while the optical properties of which remains. The breast cancer tumor-bearing mouse could be well treated by the prepared gold nanorods with the NIR-II light intensity as low as 0.75 W/cm2. In summary, these results demonstrate the feasibility of using low illumination dose to treat tumor in the NIR-II region via the large aspect ratio gould nanoparticles.