UC Berkeley researchers have developed a new type of nanoparticle that can selectively target tumor cells and report back the presence of certain molecular markers found in its environment. The dual sided nanoparticle uses a polystyrene region on one side for cell binding and a gold region on the other for label-free biomolecular sensing capabilities via strong surface-enhanced Raman spectroscopy (SERS) signal. The technology provides an opportunity to develop therapies that find and kill cancer cells and also verify the success of treatment.
The statement from UC Berkley explains:
The tiny probes measure a few hundred nanometers in diameter — one-thousandth the width of a human hair, and one-hundredth the size of most cancer cells. The team’s insight was to combine different materials — roughened gold on one side, and smooth polystyrene on the other — onto a single probe…
The sensing side of the nanocoral relies upon a technique called surface-enhanced Raman spectroscopy (SERS), which takes advantage of the electromagnetic excitations that occur as molecules make contact with the roughened surface of a metal, such as gold. Molecules produce oscillations that resonate at signature frequencies when exposed to laser light, revealing their presence to the scientists.
The researchers verified the sensitivity of the nanocoral by measuring its ability to detect a standard chemical compound for Raman spectroscopy.
To get the nanocoral to target specific cells, the researchers took advantage of the capability to attach antibodies to polymer surfaces.
"We can tailor the nanocoral to cancer cells of interest by attaching the appropriate antibodies," said the study’s other co-lead author, Liz Wu, who conducted this research as a Ph.D. student in the Applied Science and Technology program.
The researchers demonstrated this concept by coating the polystyrene surface with antibodies that attack human epidermal growth factor receptor 2 (HER-2), a well-known target for cancer treatment since it is often over-expressed in aggressive forms of breast cancer. They confirmed with both bright field and fluorescent images that the nanocoral attached to breast cancer cells with HER-2 receptors, while control experiments showed that no binding occurred when different antibodies or when cells lacking HER-2 were used.