It has long been known that heat is an effective weapon against tumor cells. However, it's difficult to heat patients' tumors without damaging nearby tissues.
Now, MIT researchers have developed tiny gold particles that can home in on tumors, and then, by absorbing energy from near-infrared light and emitting it as heat, destroy tumors with minimal side effects.
Such particles, known as gold nanorods, could diagnose as well as treat tumors, says MIT graduate student Geoffrey von Maltzahn, who developed the tumor-homing particles with Sangeeta Bhatia, professor in the Harvard-MIT Division of Health Sciences and Technology (HST) and in the Department of Electrical Engineering and Computer Science, a member of the David H. Koch Institute for Integrative Cancer Research at MIT and a Howard Hughes Medical Institute Investigator.
Von Maltzahn and Bhatia describe their gold nanorods in two papers recently published in Cancer Research and Advanced Materials. In March, von Maltzahn won the Lemelson-MIT Student Prize, in part for his work with the nanorods.
Cancer affects about seven million people worldwide, and that number is projected to grow to 15 million by 2020. Most of those patients are treated with chemotherapy and/or radiation, which are often effective but can have debilitating side effects because it's difficult to target tumor tissue.
With chemotherapy treatment, 99 percent of drugs administered typically don't reach the tumor, said von Maltzahn. In contrast, the gold nanorods can specifically focus heat on tumors.
"This class of particles provides the most efficient method of specifically depositing energy in tumors," he said.Wiping out tumors
In a study reported in the team's Cancer Research paper, tumors in mice that received an intravenous injection of nanorods plus near-infrared laser treatment disappeared within 15 days. Those mice survived for three months with no evidence of reoccurrence, until the end of the study, while mice that received no treatment or only the nanorods or laser, did not.
Once the nanorods are injected, they disperse uniformly throughout the bloodstream. Bhatia's team developed a polymer coating for the particles that allows them to survive in the bloodstream longer than any other gold nanoparticles (the half-life is greater than 17 hours).
In designing the particles, the researchers took advantage of the fact that blood vessels located near tumors have tiny pores just large enough for the nanorods to enter. Nanorods accumulate in the tumors, and within three days, the liver and spleen clear any that don't reach the tumor.
During a single exposure to a near-infrared laser, the nanorods heat up to 70 degree Celsius, hot enough to kill tumor cells. Additionally, heating them to a lower temperature weakens tumor cells enough to enhance the effectiveness of existing chemotherapy treatments, raising the possibility of using the nanorods as a supplement to those treatments.
The nanorods could also be used to kill tumor cells left behind after surgery. The nanorods can be more than 1,000 times more precise than a surgeon's scalpel, says von Maltzahn, so they could potentially remove residual cells the surgeon can't get.Finding tumors
In the Advanced Materials paper, the researchers showed they could enhance the nanorods' imaging abilities by adding molecules that absorb near-infrared light to their surface. Because of this surface-enhanced Raman scattering, very low concentrations of nanorods - to only a few parts per trillion in water [gf1]- can be detected.
Another advantage of the nanorods is that by coating them with different types of light-scattering molecules, they can be designed to simultaneously gather multiple types of information - not only whether there is a tumor, but whether it is at risk of invading other tissues, whether it's a primary or secondary tumor, or where it originated.
Bhatia and von Maltzahn are looking into commercializing the technology. Before the gold nanorods can be used in humans, they must undergo clinical trials and be approved by the FDA, which von Maltzahn says will be a multi-year process.
Other authors of the Advanced Materials paper are Andrea Centrone, postdoctoral associate in chemical engineering; Renuka Ramanathan, undergraduate in biological engineering; Alan Hatton, the Ralph Landau Professor of Chemical Engineering; and Michael Sailor and Ji-Ho Park of the University of California at San Diego.
Park and Sailor are also authors of the Cancer Research paper, along with Amit Agrawal, former postdoctoral associate in HST; and Nanda Kishor Bandaru and Sarit Das of the Indian Institute of Technology Madras.
The research was funded by the National Institutes of Health, the Whitaker Foundation and the National Science Foundation. Nanopartz Inc. supplied gold nanoparticles, gold nanowires and the precursor gold nanorods used in this work.
Elizabeth Thomson | EurekAlert!
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences