Delivery and cytotoxicity of doxorubicin and temozolomide to primary glioblastoma cells using gold nanospheres and gold nanorods

Nanoparticles with coating entrapping a chemotherapeutic drug for delivery have not been tested for their cytotoxic effects in in-vitro glioblastoma cell cultures to increase treatment efficacy. Therefore, we synthesized silica-coated gold nanorods and gold nanospheres that were loaded with doxorubicin or temozolomide. The morphology of the nanoparticles was characterized using transmission electron microscopy (TEM), the molecular structure was characterized using infrared spectroscopy and in vitro efficacy was determined using glioblastoma cell cultures. TEM analysis showed that gold nanorods had a length of 49-65 nm and a diameter of 8.5-14 nm whereas gold nanospheres had a diameter of 9.5-37 nm. Infrared spectroscopy of doxorubicin and temozolomide and the silica coating revealed molecular fingerprints such as bending, stretching and vibrations of chemical bonds that confirmed the presence of silica coating and drug loading of the gold nanoparticles. In the biological assessment of the effects of drug-loaded gold nanoparticles on primary glioblastoma cell cultures, cytotoxicity, viability and the ratio of cyototoxicity and viability were used as parameters to analyze the effects on the cells of drug delivery via gold nanoparticles on the cells. Our data suggest that doxorubicin in the concentration range of 0.12-3.16 μM when delivered using both gold nanorods and nanospheres induced a 3.8-5.5-fold increased cytotoxicity in comparison to direct delivery. Temozolomide in the concentration range of 4.6-115 μM when delivered by either type of gold nanoparticles induced a 2-4-fold increased cytotoxicity in comparison to direct delivery. Nanospheres were more effective in delivery and cytotoxicity of doxorubicin and temozolomide to glioblastoma cells than gold nanorods. Our data suggest that gold nanoparticles and in particular gold nanospheres are more effective in delivery of doxorubicin and temozolomide to primary glioblastoma cells in culture than direct delivery.