Bovine serum albumin nanospheres synchronously encapsulating "gold selenium/gold" nanoparticles and photosensitizer for high-efficiency cancer phototherapy.

Gold nanostructures have generated significant attention in biomedical areas because of their major role in cancer photothermal therapeutics. In order to conveniently combine gold nanostructures and drugs into one nanocomposite, Au2Se/Au core-shell nanostructures with strong near-infrared-absorbing properties were synthesized using a simple method and embedded inside bovine serum albumin (BSA) nanospheres by using a spray dryer equipped with an ultrasonic atomizer followed by thermal denaturation. The nanospheres with narrow size distribution mainly ranging from 450 to 600 nm were obtained. The Au2Se/Au-loaded BSA nanospheres (1 mg) adsorbed at least 0.01 mg of water-insoluble zinc phthalocyanine (ZnPc) photosensitizer. After irradiation with a 655-nm laser (20 min), the temperature of the Au2Se/Au-loaded BSA nanospheres [200 μL, 2 mg/mL, BSA/Au2Se/Au 10:1 (w/w)] increased by over 20 °C from the initial temperature of 24.82 ± 0.15 °C, and the release of ZnPc was improved compared with a corresponding sample without irradiation. After being incubated with cancer cells (human esophageal carcinoma Eca-109), the nanospheres exhibited photothermal and photodynamic therapy with a synergistic effect upon laser irradiation. This work provides novel Au2Se/Au-loaded polymer nanospheres prepared by a high-efficiency strategy for incorporating drugs for improving the efficiency in killing cancer cells.