Low-cost sensor detects early Parkinson’s in a sample – 03/28/2023 – Health

Researchers from the State University of Campinas (Unicamp) and Federal University of São Carlos (UFSCar) have developed an electrochemical sensor that detects Parkinson’s disease at different stages. Manufactured in a common 3D printer, the device can anticipate the diagnosis, allowing early treatment, and even works as a model for the identification of other diseases, according to an article published in the journal Sensors and Actuators B: Chemical.

“The sensor quickly indicates the concentration of the PARK7/DJ-1 protein in human blood plasma and synthetic cerebrospinal fluid. The molecule is linked to Parkinson’s disease at levels below 40 micrograms per liter [40 μg/L]”, explains Cristiane Kalinke, postdoctoral student at Unicamp’s Institute of Chemistry (IQ-Unicamp), visiting researcher at Manchester Metropolitan University (United Kingdom) and first author of the article. “With the advantage of being able to be printed in different formats and sizes, including miniature, creating truly portable devices that require a very small amount of sample.”

To build the sensor, the researchers used a commercial filament composed basically of polylactic acid (biodegradable polymer known by the acronym PLA) associated with a conductive material (graphene) and other additives. Three electrodes were printed in plastic with 3D technology and underwent a chemical treatment that made them even more conductive and stimulated the formation of functional groups (carboxylic) on their surfaces, which bind with antibodies. The activation process involved removing the insulating polymer surface from the electrodes by immersion in sodium hydroxide (NaOH) and applying an electrical potential (positive and negative). Then, the specific reaction between the antibodies and the PARK7/DJ-1 protein is promoted to provide the diagnosis.

The next steps of the work, which had support from Fapesp (projects 13/22127-2, 17/21097-3, 19/00473-2 and 21/07989-4), were to immobilize specific antibodies for PARK7/DJ-1 on the surface of the electrodes and apply the sensor to detect the protein at three concentration levels: 30 μg/L, 40 μg/L and 100 μg/L. The mean concentration in patients diagnosed with Parkinson’s at different stages is approximately 30 ± 9 μg/L, according to data in the literature.

“It is difficult for a patient to go to a medical consultation in search of a routine exam to detect Parkinson’s in its initial stage — when there is suspicion, probably physical and behavioral symptoms have already manifested and the disease is already well established”, says Juliano Alves Bonacin, professor from the Department of Inorganic Chemistry at the Institute of Chemistry at Unicamp (IQ-Unicamp) and supervisor of the study. “Our idea was to build a very simple and very inexpensive device that would allow monitoring over time and trigger an alert to doctors and patients in case of changes in PARK7/DJ-1 levels, which is especially useful if analyzed together with other biomarkers.”

Concept proof

An important legacy of the study is to function as a proof of concept by demonstrating the versatility of this type of impression as a platform for the immobilization of biomolecules.

“We were able to print all the components of an electrochemical cell on a 3D printer, using only a polymer as a conductive material”, says Kalinke. “In this specific work, the materials were commercial, that is, they were purchased ready-made, but, little by little, we are developing new filaments for 3D printing in our laboratory as well.”

According to the authors, the platform opens doors to the diagnosis of other diseases — in the case of the PARK7/DJ-1 protein specifically, in addition to neurological problems, there is a relationship with type 2 diabetes, infertility and some types of cancer. But the goal is to expand its use to other biomarkers and, by the way, Kalinke is already working on manufacturing a sensor for diagnosing yellow fever.

“Imagine that there is an outbreak of a certain disease in a specific region”, exemplifies Bonacin. “With a few 3D printers and some electrodes it would be possible to produce a sensor like ours on site.”

The study also had the collaboration of Craig E. Banks, professor at the Faculty of Science and Engineering at the Manchester Metropolitan University, professor Bruno Campos Janegitz and researcher Paulo Roberto de Oliveira, both from UFSCar – Campus Araras.

The article “3D-printed immunosensor for the diagnosis of Parkinson’s disease” can be read here.