New biosensor can detect Alzheimer’s and Parkinson’s molecules

23 May 2016

A team of Brazilian researchers has created an advanced biosensor capable of detecting molecules associated with neurodegenerative diseases, such as Alzheimer’s and Parkinson’s, and some types of cancer.

The biosensor is the work of a team from the National Nanotechnology Laboratory (LNNano) in Campinas, São Paulo State, and came about as part of a project to develop a point-of-care device using functional materials to produce simple sensors, as well as microfluidic systems with a short turnaround in results.

Consisting of a single-layer organic nanometre-scale transistor on a glass slide, the electronic device contains the reduced form of a chemical called peptide glutathione (GSH).

Affordable and portable

This compound reacts in a specific way when it comes into contact with the enzyme glutathione S-transferase (GST), which has been linked to the development of Parkinson’s, Alzheimer’s and breast cancer, among other diseases.

Once the reaction between GSH and GST begins, the biosensor is then able to detect it, allowing it to then be used by medical professionals to quickly diagnose the potential development of such conditions.

Crucially, this new biosensor promises to be not only very affordable, but also portable, without a drop-off in sensitivity to picking up the chemical reaction that you would imagine occurs with a cheaper and smaller device.


The newly-developed, affordable biosensor. Image via LNNano

“This is the first time organic transistor technology has been used in detecting the pair GSH-GST, which is important in diagnosing degenerative diseases, for example,” said the head of LNNano, Carlos Cesar Bof Bufon.

“The device can detect such molecules even when they’re present at very low levels in the examined material, thanks to its nanometric sensitivity.”

Next stop, paper

The next stage of the project is to take this device and look at the possibility of creating a paper-based biosensor, which would allow for an even cheaper and more portable sensor that could also be disposable in a medical facility.

The biggest challenge that paper poses, however, is that it is an insulator in its usual form, but the team has managed to find a possible way of overcoming this.

It has done this by developing a technique that makes paper conductive and capable of transporting sensing data by impregnating cellulose fibres with polymers that have conductive properties.

This is achieved by a process referred to as gas-phase chemical polymerisation, which inserts liquid oxidant into the paper, which gives it conductive properties.

This can be adjusted by manipulating the element embedded in the cellulose fibres, depending on the application, allowing for sensors that could have multiple functions as a physical, chemical or electrochemical sensor.

CT scan image via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic