Nanoshells Deliver Drugs as Smart Bombs to Cancer Cells
Scientists in China say they have created nanoparticles that are capable of delivering drugs to targeted cancer cells. According to the research team, the multifunctional “smart” gold nanoshells could lead to more effective cancer treatments by overcoming a major limitation of modern chemotherapy techniques—the ability to zero in on specific cancer cells and leave healthy cells untouched.
Small peptides situated on the surface of the nanoshells are the key to the improved targeting ability, guiding the nanoshells to specific cancer cells and attaching to markers on the surface of the cells, explains Shunying Liu, Ph.D., a scientist at East China Normal University. The acidic environment of the cancer cells then triggers the offloading of the anticancer drugs.
The specific nanostructure of the gold nanoshells could also allow near-infrared light to be absorbed and converted into heat, opening up the possibility of using the nanoshells in targeted hyperthermia treatment—another form of cancer treatment whereby cancer cells are exposed to slightly higher temperatures than usual to destroy them.
The results of the nanoshells’ study (“Smart gold nanoshells for combined cancer chemotherapy and hyperthermia”) are published in Biomedical Materials.
The researchers, from East China Normal University and Tongji University, used the gold nanoshells as a building block to which they attached the commonly used anticancer drug doxorubicin (DOX) and a specific peptide known as A54. The gold nanoshells had diameters of around 200 nanometers (more than 50 times smaller than a red blood cell).
“DOX-modified GNs [gold nanoshells] showed pH-dependent release behavior, and the in vitro cell uptake experiment using ICP-AES [inductively coupled plasma atomic emission spectroscopy] and microscopy showed greater internalization of A54-modified GNs in the human liver cancer cell line BEL-7402 than of those without A54,” wrote the investigators. “Flow cytometry and fluoroscopy analysis were conducted to reveal the enhanced cell apoptosis caused by the A54-modified GNs under combined chemotherapeutic and hyperthermia therapies. These results imply that DOX/A54@GNs could be used as a multifunctional nanomaterial system with pH-triggered drug-releasing properties for tumor-targeted chemotherapy and hyperthermia.”
The next step of this research will be to test the smart gold nanoshells in vivo on a liver cancer mouse model, notes Dr. Liu. “We will also examine how the size of the nanoshells changes their efficacy and how efficient the nanoshells are at converting near-infrared light into heat,” she says.