Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Tiny, brightly shining silicon crystals could be safe for deep-tissue imaging: In a new study, the crystals had no toxic effects in non-human primates

Bright light emission from silicon quantum dots in a cuvette. The image is from a camera that captures the near-infrared light that the quantum dots emit. The light emission shown is a psuedo color, as near-infrared light does not fall in the visible spectrum. Credit: Folarin Erogbogbo
Bright light emission from silicon quantum dots in a cuvette. The image is from a camera that captures the near-infrared light that the quantum dots emit. The light emission shown is a psuedo color, as near-infrared light does not fall in the visible spectrum.

Credit: Folarin Erogbogbo

Abstract:
Tiny silicon crystals caused no health problems in monkeys three months after large doses were injected, marking a step forward in the quest to bring such materials into clinics as biomedical imaging agents, according to a new study.

Tiny, brightly shining silicon crystals could be safe for deep-tissue imaging: In a new study, the crystals had no toxic effects in non-human primates

Buffalo, NY | Posted on July 31st, 2013

The findings, published online July 10 in the journal ACS Nano, suggest that the silicon nanocrystals, known as quantum dots, may be a safe tool for diagnostic imaging in humans. The nanocrystals absorb and emit light in the near-infrared part of the spectrum, a quality that makes them ideal for seeing deeper into tissue than traditional fluorescence-based techniques.

"Quantum dots, or nanocrystals, are very, very promising for biomedical imaging applications, but everyone's worried about the toxicity and what will happen to them if they degrade," said co-lead author Folarin Erogbogbo, PhD, a University at Buffalo research assistant professor who has since accepted a new position as an assistant professor of biomedical engineering at San Jose State University. "Silicon nanocrystals can be the solution to that because they don't contain materials like cadmium that are found in other quantum dots, and are generally considered to be nontoxic."

The study was a collaboration between UB, Chinese PLA General Hospital in China, San Jose State University, Nanyang Technological University in Singapore and Korea University in South Korea. It's part of a larger body of research that many of the team members have been conducting to investigate the effect of various nanoparticles in animal models.

The researchers tested the silicon quantum dots in rhesus macaques and mice, injecting each animal with 200 milligrams of the particles per kilogram of the animal's weight.

Blood tests taken for three months afterward showed no signs of toxicity in either the mice or monkeys, and all of the animals appeared healthy over the course of the study. The subjects ate, drank, groomed, explored and urinated normally.

The silicon crystals did, however, gather and stay in the livers and spleens of the mice, resulting in side effects including inflammation and spotty death of liver cells.

Interestingly, the same thing did not happen with the rhesus macaques: The monkeys' organs appeared normal, without the damage seen in the mice.

This discrepancy raises the question of how useful toxicity studies on mice can be in determining a nanocrystal's potential effect on humans, said co-author Paras Prasad, PhD, SUNY Distinguished Professor in chemistry, physics, electrical engineering and medicine at UB, and executive director of UB's Institute for Lasers, Photonics and Biophotonics.

Quantum dots and other nanoparticles — because of their tiny size — can access parts of the body where larger particles just can't go. Due to this and other factors, the differences in anatomic scale between mice and primates may matter more in nanomedicine than in other pharmaceutical fields, Prasad said.

"Even at high doses, we didn't see any adverse side effects at all in monkeys despite the problems in mice," Prasad said. "This is the first test of these silicon quantum dots in primates, and the research results mark a step forward toward potential clinical applications."

The fact that the silicon did not biodegrade in the mice was very surprising, said co-author Mark Swihart, PhD, a UB professor of chemical and biological engineer and co-director of UB's New York State Center of Excellence in Materials Informatics.

"Generally, people assume that silicon quantum dots will biodegrade," Swihart said. "We didn't see that happen, and we think this might be due to the fact that we capped the surface with organic, FDA-approved molecules to keep the quantum dots from degrading too fast.

"We may have done too good of a job of protecting them," Swihart continued. "If you really kept your car beautifully waxed all the time, it would never rust. That's what we've done with these quantum dots."

####

For more information, please click here

Contacts:
Charlotte Hsu
Media Relations Manager
Architecture, Economic Development
Sciences, Urban and Regional Planning

716-645-4655
Twitter: @UBScience
Pinterest: UB Science

Copyright © University at Buffalo

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Download article:

Related News Press

News and information

In IEDM 2016 Keynote, Leti CEO Says ‘Hyperconnectivity’, Human-focused Research and the IOT Promise Profound, Positive Changes December 7th, 2016

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Imaging

Deep insights from surface reactions: Researchers use Stampede supercomputer to study new chemical sensing methods, desalination and bacterial energy production December 2nd, 2016

Controlled electron pulses November 30th, 2016

Novel silicon etching technique crafts 3-D gradient refractive index micro-optics November 28th, 2016

Scientists shrink electron gun to matchbox size: Terahertz technology has the potential to enable new applications November 25th, 2016

Discoveries

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Fast, efficient sperm tails inspire nanobiotechnology December 5th, 2016

Announcements

In IEDM 2016 Keynote, Leti CEO Says ‘Hyperconnectivity’, Human-focused Research and the IOT Promise Profound, Positive Changes December 7th, 2016

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Fast, efficient sperm tails inspire nanobiotechnology December 5th, 2016

Journal Nanotechnology Progress International (JONPI) Volume 6, issue 2 coming out soon! December 5th, 2016

Safety-Nanoparticles/Risk management

First time physicists observed and quantified tiny nanoparticle crossing lipid membrane November 7th, 2016

SUN shares its latest achievements during the 3rd Annual Project Meeting November 1st, 2016

The Sustainable Nanotechnologies Project’s Final Events: Bringing Nano Environmental Health and Safety Assessment to the Wider Discussion on Risk Governance of Key Enabling Technologies November 1st, 2016

Exploding smartphones: What's the silent danger lurking in our rechargeable devices? New research identifies toxic emissions released by lithium-ion batteries October 21st, 2016

Quantum Dots/Rods

Trickling electrons: Close to absolute zero, the particles exhibit their quantum nature November 10th, 2016

Notre Dame researchers find transition point in semiconductor nanomaterials September 6th, 2016

Quantum dots with impermeable shell: A powerful tool for nanoengineering August 12th, 2016

Diamond-based light sources will lay a foundation for quantum communications of the future: Electrified quantum diamond can become the heart of quantum networks and computers of the future August 7th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project