Multifunctional optical probe based on gold nanorods for detection and identification of cancer cells

In this paper, we report that localized surface plasmon resonance (LSPR) absorption and fluorescence properties of gold nanorods can be used for rapid, highly sensitive and selective detection and identification of cancer cells from normal cells. A multifunctional optical probe for quantitative detection, identification and imaging of cancer cells has been fabricated based on folic acid-conjugated gold nanorods (F-GNRs). To investigate the targeting performance of the probe, human cervical carcinoma (HeLa) cells were used as model cancer cells and African green monkey kidney (Vero) cells as model normal cells. The experimental results indicate that the fluorescence intensity increment and the absorption value decrement are highly sensitive to the concentration of HeLa cells over the range of 100–5000 cells/mL, and the intensity changed linearly with concentration. Simultaneously, a detection limit to detect HeLa cells as low as 70 cells/mL and 10 cells/mL, respectively. Interference experiments show that spectrum change rate not to exceed 1.43% and 2.5% when F-GNRs were mixed with a certain amount of HeLa cells and various concentrations of Vero cells. The protocol offers high selectivity for the detection of HeLa cancer cells among normal cells. By using fluorometric and colorimetric method for detection of practical samples, when fluorescence intensity of cancer cells increases 6 times and absorption value decreases 10 times than the normal cells sample can be distinguished clearly by a significant difference of ΔFI and ΔA. Significantly, the detection and discrimination process cannot only be monitored by changes in the absorption of light and fluorescence intensity, but is also observable by the naked eye. The assay could be adapted in studies using antibodies specific for various cancer cells for the detection of a wide variety of cancer cells in the fields such as biochemistry, biomedical, and clinical analysis.