Glowing cellular probe
doi:10.1038/nindia.2011.153 Published online 29 October 2011
Researchers have designed a new nanosized magnetofluorescent hybrid probe that is capable of detecting and imaging physiological anomalies down to the level of cells. This nanosized probe will be very useful for detecting disease at an early stage.
Hybrid nanoparticles are versatile probes that combine magnetic and optical properties on a single platform, yielding tools that can image, detect and separate cells and molecules. However, assembling nanoparticles on a single platform has several drawbacks, one being that the gold nanorods used in such hybrid nanoprobes are unstable at high temperatures.
To avoid this problem, the researchers devised an alternative way of making hybrid nanoparticles containing gold nanorods. They prepared gold nanorods in the presence of cetyltrimethyl ammonium bromide and then modified the resulting nanorods with mercaptoundecanol and mercaptoundecanoic acid. Then they separately produced polyacrylate-coated zinc-sulphide-coated cadmium selenide quantum dots. They also prepared polyacrylate-coated iron oxide nanoparticles through a similar process. Finally, the researchers combined these three types of nanoparticle to produce hybrid nanoparticles.
To investigate the imaging and detection potential of the hybrid nanoparticles, the nanoprobes were cultured with liver cancer cells and rat heart cells and then irradiated with white light in front of either a dark or light background. The nanoprobes were modified with glucose and oleylamine prior to culture and irradiation, which helped the nanoprobes bind to the membranes of liver cancer cells and rat heart cells.
The imaging results showed that hybrid nanoprobes were visible mainly at the surface. The component nanoparticles in the hybrid nanoprobes remained intact and were not separated after attaching to cells. The gold nanorods were dark-brown when in front of the light background and orange when in front of the dark background.
"These nanoprobes will be very useful for detecting molecules inside the cell, down to single-molecule level," says lead researcher Nikhil R. Jana.
Basiruddin, S. K. et al. Gold-nanorod-based hybrid cellular probe with multifunctional properties. J. Phys. Chem. C. 115, 19612-19620 (2011) | Article |