Researchers have developed a novel hybrid nanoprobe that may lead to non-invasive recognition and treatment of cancer at the cellular level, according to a new report in the journal Nature Communications.
Using two pieces of a fluorescent protein as “molecular glue,” the new technique attaches gold nanoparticles to distinct biomarkers on the exterior of cancer cells. These particles function as amplifiers for biomarkers such as overexpressed or mutated proteins that are tell-tale signs a cell is cancerous.
Once the signals have been amplified, scientists can then differentiate cancerous and healthy cells using Raman spectroscopy.
Our approach takes advantage of the fact that we have two different nanoparticles which, on their own, are not active, but which become active when they assemble on cancer cells.
Fabien Pinaud, Study Author & Assistant Professor of Biological Sciences, Chemistry, Physics & Astronomy - USC Dornsife
(See news release here)
Using “molecular glue” units to create novel nanoprobes is typical practice in biomedical study, but most researchers build these with DNA as opposed to protein. While encouraging optical probes are being produced using DNA structures in test tubes, DNA is not a sensible adhesive in live cells; proteins tend to do a better job.
In the study, researchers began with a fluorescent protein that glows when struck by ultraviolet-blue light. The fluorescent protein is separated into two fragments, and each part is linked to a group of gold nanoparticles. Both sets of nanoparticles target cells and bind explicitly to biomarkers at the cell exterior. As the nanoparticles clash together on a cancer cell, the protein pieces naturally reassemble into the complete fluorescent protein.
The restructuring sequence offers two advantages. Firstly, the triggering of a new biochemical signal in the fluorescent protein is vastly enhanced by the nanoparticles, which enables detection via Raman spectroscopy. Secondly, when the Raman laser hits the nanoparticles, it generates heat and ultrasonic noise that can be measured. This dual effect supplies a high degree of confidence that a given cell is cancerous and not a false-positive signal from a good cell.
Study researchers said they plan to investigate the potential for eradicating individual cancer cells while leaving healthy cells untouched by a laser to heat the nanoparticles.
“Going from imaging to killing cells is just about turning the knob on the laser that you use,” Pinaud said.
Another approach might be using gold nanoparticles to deliver cancer drugs in an extremely targeted manner. A study published last month described how researchers created a technology that permits medications to be shipped and released only at the diseased tissue targeted by the drug. The new technique uses a distinctive polymer coating made from gold nanoparticles, which releases medication when light strikes the gold particles, causing them to melt.
The scientists developed the unique delivery technique that released under longwave, near-infrared light (NIR). The principal benefit of NIR light is its ability permeate bodily tissues without damaging them.
"We've developed a material with varying melting points, allowing us to control it using low intensities," said Boaz Mizrahi, one of the researchers behind the novel drug delivery technique. "Our system is composed of FDA-approved materials, and we are relatively close to clinical application."
The study team said their research could be utilized for a wide variety of other uses, like closing of injuries, positioning of tissue during surgery, or as biodegradable structures for growing transplant organs.
"The next step will include creating particles that include the drugs so that we can test their improved effectiveness using this delivery technology,” Mizrahi said.