Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Molecules 'light up' Alzheimer's roots: Rice University lab's light-switching complex attaches itself to amyloid proteins

Amyloid fibrils like those magnified here 12,000 times are thought to be the cause of plaques in the brains of Alzheimer's disease patients. Rice University researchers have created a metallic molecule that becomes strongly photoluminescent when it attaches to fibrils.
(Credit: Nathan Cook/Rice University)
Amyloid fibrils like those magnified here 12,000 times are thought to be the cause of plaques in the brains of Alzheimer's disease patients. Rice University researchers have created a metallic molecule that becomes strongly photoluminescent when it attaches to fibrils. (Credit: Nathan Cook/Rice University)

Abstract:
A breakthrough in sensing at Rice University could make finding signs of Alzheimer's disease nearly as simple as switching on a light.

Molecules 'light up' Alzheimer's roots: Rice University lab's light-switching complex attaches itself to amyloid proteins

Houston, TX | Posted on July 13th, 2011

The technique reported in the Journal of the American Chemical Society should help researchers design better medications to treat the devastating disease.



The lab of Rice bioengineer Angel Martí is testing metallic molecules that naturally attach themselves to a collection of beta amyloid proteins called fibrils, which form plaques in the brains of Alzheimer's sufferers. When the molecules, complexes of dipyridophenazine ruthenium, latch onto amyloid fibrils, their photoluminescence increases 50-fold.

The large increase in fluorescence may be an alternative to molecules currently used to study amyloid fibrils, which researchers believe form when misfolded proteins begin to aggregate. Researchers use changes in fluorescence to characterize the protein transition from disordered monomers to aggregated structures.

Nathan Cook, a former Houston high school teacher and now a Rice graduate student and lead author of the new paper, began studying beta amyloids when he joined Martí's lab after taking a Nanotechnology for Teachers course taught by Rice Dean of Undergraduates and Professor of Chemistry John Hutchinson. Cook's goal was to find a way to dissolve amyloid fibrils in Alzheimer's patients.

But the Colorado native's research led him down a different path when he realized the ruthenium complexes, the subject of much study in Martí's group, had a distinctive ability to luminesce when combined in a solution with amyloid fibrils.

Such fibrils are simple to make in the lab, he said. Molecules of beta amyloid naturally aggregate in a solution, as they appear to do in the brain. Ruthenium-based molecules added to the amyloid monomers do not fluoresce, Cook said. But once the amyloids begin to aggregate into fibrils that resemble "microscopic strands of spaghetti," hydrophobic parts of the metal complex are naturally drawn to them. "The microenvironment around the aggregated peptide changes and flips the switch" that allows the metallic complexes to light up when excited by a spectroscope, he said.

Thioflavin T (ThT) dyes are the standard sensors for detecting amyloid fibrils and work much the same way, Marti said. But ThT has a disadvantage because it fluoresces when excited at 440 nanometers and emits light at 480 nanometers -- a 40-nanometer window.

That gap between excitation and emission wavelengths is known as the Stokes shift. "In the case of our metal complexes, the Stokes is 180 nanometers," said Martí, an assistant professor of chemistry and bioengineering. "We excite at 440 and detect in almost the near-infrared range, at 620 nanometers.

"That's an advantage when we want to screen drugs to retard the growth of amyloid fibrils," he said. "Some of these drugs are also fluorescent and can obscure the fluorescence of ThT, making assays unreliable."

Cook also exploited the metallic's long-lived fluorescence by "time gating" spectroscopic assays. "We specifically took the values only from 300 to 700 nanoseconds after excitation," he said. "At that point, all of the fluorescent media have pretty much disappeared, except for ours. The exciting part of this experiment is that traditional probes primarily measure fluorescence in two dimensions: intensity and wavelength. We have demonstrated that we can add a third dimension -- time -- to enhance the resolution of a fluorescent assay."

The researchers said their complexes could be fitting partners in a new technique called fluorescence lifetime imaging microscopy, which discriminates microenvironments based on the length of a particle's fluorescence rather than its wavelength.

Cook's goal remains the same: to treat Alzheimer's -- and possibly such other diseases as Parkinson's -- through the technique. He sees a path forward that may combine the ruthenium complex's ability to target fibrils and other molecules' potential to dissolve them in the brain.

"That's something we are actively trying to target," Martí said.

Co-authors of the paper are recent Rice graduate Veronica Torres and Disha Jain, a former postdoctoral researcher in Martí's lab.

The Welch Foundation supported the research.

####

About Rice University
Located on a 285-acre forested campus in Houston, Texas, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is known for its “unconventional wisdom." With 3,485 undergraduates and 2,275 graduate students, Rice's undergraduate student-to-faculty ratio is less than 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 4 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to futureowls.rice.edu/images/futureowls/Rice_Brag_Sheet.pdf.

For more information, please click here

Contacts:
David Ruth
713-348-6327


Mike Williams
713-348-6728

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 News Press

News and information

Happily ever after: Scientists arrange protein-nanoparticle marriage: New biotech method could lead to development of HIV vaccine, targeted cancer treatment April 20th, 2015

Nondestructive 3-D Imaging of Biological Cells with Sound April 20th, 2015

Advances in molecular electronics: Lights on -- molecule on: Researchers from Dresden and Konstanz succeed in light-controlled molecule switching April 20th, 2015

Yale-NUS, NUS and UT Austin researchers establish theoretical framework for graphene physics: Making strides towards using graphene to create new electronic devices April 20th, 2015

Imaging

Nondestructive 3-D Imaging of Biological Cells with Sound April 20th, 2015

Nanomedicine

Happily ever after: Scientists arrange protein-nanoparticle marriage: New biotech method could lead to development of HIV vaccine, targeted cancer treatment April 20th, 2015

Optical resonance-based biosensors designed for medical applications April 18th, 2015

Nanocomposites Play Effective Role in Production of Smart Fibers April 18th, 2015

Novel nanoparticles could save soldiers' lives after explosions April 15th, 2015

Sensors

Optical resonance-based biosensors designed for medical applications April 18th, 2015

MIT sensor detects spoiled meat: Tiny device could be incorporated into 'smart packaging' to improve food safety April 15th, 2015

Graphene pushes the speed limit of light-to-electricity conversion: Researchers from ICFO, MIT and UC Riverside have been able to develop a graphene-based photodetector capable of converting absorbed light into an electrical voltage at ultrafast timescales April 14th, 2015

Iranian Scientists Evaluate Dynamic Interaction between 2 Carbon Nanotubes April 14th, 2015

Discoveries

Happily ever after: Scientists arrange protein-nanoparticle marriage: New biotech method could lead to development of HIV vaccine, targeted cancer treatment April 20th, 2015

Nondestructive 3-D Imaging of Biological Cells with Sound April 20th, 2015

Advances in molecular electronics: Lights on -- molecule on: Researchers from Dresden and Konstanz succeed in light-controlled molecule switching April 20th, 2015

Yale-NUS, NUS and UT Austin researchers establish theoretical framework for graphene physics: Making strides towards using graphene to create new electronic devices April 20th, 2015

Alliances/Partnerships/Distributorships

How can you see an atom? (video) April 10th, 2015

FibeRio and VF Corporation Form Strategic Partnership to Lead the Apparel and Footwear Markets in Nanofiber Technology April 8th, 2015

UK National Graphene Institute Selects Bruker as Official Partner: World-Leading Graphene Research Facility Purchases Multiple Bruker AFMs April 7th, 2015

NXP and GLOBALFOUNDRIES Announce Production of 40nm Embedded Non-Volatile Memory Technology: Co-developed technology to leverage GLOBALFOUNDRIES 40nm process technology platform March 24th, 2015

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







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE