Originally his team tried to create intense electromagnetic hot spots by sticking smaller particles onto a larger central particle, creating core-satellite assemblies that look like daisies.
"But we realized these assemblies are not ideal for bioimaging," he says, "because the particles were held together by weak electrostatic interactions and the assemblies were going to come apart in the body."
Next they tried using something called Click chemistry to make stronger covalent bonds between the satellites and the core.
"We had some success with those assemblies," Singamaneni says, "but in the meantime we had started to wonder if we couldn't make an electromagnetic hot spot within a single nanoparticle rather than among particles.
"It occurred to us that if we put Raman reporters between the core and shell of a single particle could we create an internal hotspot."
That idea worked like a charm.
A rainbow of probes carefully dispensing drugs?
The next step, says Singamaneni, is to test BRIGHTS in vivo in the lab of Sam Achilefu, PhD, professor of radiology in the School of Medicine.
But he's already thinking of ways to get even more out of the design.
Since different Raman reporter molecules respond at different wavelengths, Singamaneni says, it should be possible to design BRIGHTS targeted to different biomolecules that also have different Raman reporters and then monitor them all simultaneously with the same light probe.
And he and Gandra would like to combine BRIGHTS with a drug container of some kind, so that the containers could be tracked in the body and the drug and released only when it reached the target tis
|Contact: Diana Lutz|
Washington University in St. Louis