Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Biosensor reveals new information about suspected cause of Alzheimer’s disease


Chemists and biologists at Northwestern University have found a way to detect and estimate the size and structure of a miniscule toxic protein suspected of triggering Alzheimer’s disease. The findings, researchers say, could help scientists better understand the underlying mechanisms of the disease and lead to the development of new treatments that could slow or possibly arrest its progression.

The findings also could potentially be used to diagnose Alzheimer’s disease in living people instead of during an autopsy, says Amanda J. Haes, Ph.D., a co-author of the study. At present, Alzheimer’s can only be accurately diagnosed after death.

Haes, a National Research Council postdoctoral researcher at the Naval Research Laboratory in Washington, conducted this work while she was a graduate student at Northwestern under the direction of Richard Van Duyne. The findings were presented today at the 230th national meeting of the American Chemical Society, the world’s largest scientific society.

Haes, in cooperation with Van Duyne, Northwestern professor William Klein and research associate Lei Chang developed a method to detect small harmful proteins in cerebrospinal fluid using nanoscale optical biosensors. The proteins, known as ADDLs (amyloid ?-derived diffusible ligands) are so small that they can’t be detected by conventional diagnostic tests. They are usually less than 5 nanometers wide and are found in extremely low concentrations.

Discovered by Klein in 1998, ADDLs accumulate in the brain tissue of individuals with Alzheimer’s disease at levels up to 70 times higher than found in people who don’t have the disease. Many researchers now suspect that ADDLs cause some of the earliest symptoms of Alzheimer’s disease. ADDLs, they theorize, attack and disrupt synapses, the sites on nerve cells that are critical for memory formation and information processing. ADDLs tend to stick together, and some researchers suspect that as they aggregate, they’re more apt to damage neurons.

"It’s becoming more evident that the size of â-amyloid (ADDL) molecules matters — that only ADDLs of a certain size cause problems for neurons in the early stages of Alzheimer’s disease," Haes says. "These nanoscale biosensors may one day allow us to determine, based on size, if an individual has ADDLs that will affect his or her cognitive function. However, there are still many hurdles that must be overcome before we can use it as a diagnostic tool."

The biosensors developed by the Northwestern team are based on tiny, triangular silver particles that absorb and scatter light. On the outside surfaces of nanoparticles is a layer of ADDL-specific antibodies. These antibodies bind specifically to any ADDL molecules found in cerebrospinal fluid. When this happens, the color of the silver nanoparticles shifts slightly. The researchers detected these color shifts using a specialized light detector called ultraviolet-visible spectrometer. In a small sample pool, comparing cerebrospinal fluid extracted from two people diagnosed with Alzheimer’s disease and two people who weren’t, Haes found that ADDL levels were elevated in the diseased patient samples in comparison to control patient samples.

Alzheimer’s disease is an irreversible disorder of the brain, robbing those who have it of memory, overall mental and physical function, and eventually leading to death. It is the most common cause of dementia among people over age 65, affecting an estimated 4.5 million Americans, according to the National Institute on Aging.

The American Chemical Society is a nonprofit organization, chartered by the U.S. Congress, with a multidisciplinary membership of more than 158,000 chemists and chemical engineers. It publishes numerous scientific journals and databases, convenes major research conferences and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.

Charmayne Marsh | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht When fat cells change their colour
28.10.2016 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Aquaculture: Clear Water Thanks to Cork
28.10.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Prototype device for measuring graphene-based electromagnetic radiation created

28.10.2016 | Power and Electrical Engineering

Gamma ray camera offers new view on ultra-high energy electrons in plasma

28.10.2016 | Physics and Astronomy

When fat cells change their colour

28.10.2016 | Life Sciences

More VideoLinks >>>