A portable sensor for self-testing of urine to detect markers of diseases such as cancer, gout and Parkinson’s

Developed by Brazilian scientists, the device connects wirelessly to a smartphone and can be used to monitor general health.

By Julia Moióli  |  Agência FAPESP – A sensor developed in Brazil by researchers affiliated with the University of São Paulo (USP) and the Federal University of Viçosa (UFV) may be of great assistance to patients who require frequent monitoring of urinary biomarkers, such as people with gout who need to control uric acid levels. The device provides this information quickly and at home via connection to a smartphone, according to a study published in Chemical Engineering Journal.

With a production cost of less than BRL 0.50 (now about USD 0.10), the device contains a flexible electrode sensor strip integrated with a portable wireless analyzer that measures a broad spectrum of molecular biomarkers within three minutes of receiving a drop of human urine, without the need to submit the sample to prior stages of pretreatment. The results of the analysis are displayed by a mobile device (smartphone, laptop or tablet) via wireless communications (Bluetooth).

The tests performed during the study, which was supported by FAPESP (projects 20/09587-8, 23/07686-7, 19/01777-5, 22/02164-0, 16/01919-6 and 23/00850-6), analyzed levels of uric acid and dopamine in urine samples. 

Uric acid is a biomarker for several diseases, including hyperuricemia, Fanconi syndrome, gout, cancer, Lesch-Nyhan syndrome, kidney failure, physical stress and severe type 2 diabetes.

Dopamine is an important neuromodulator with key functions in the central nervous system, kidneys, and cardiovascular and hormone systems. Abnormal levels may reflect neurological and psychiatric disorders, including schizophrenia, depression, addiction, Alzheimer’s and Parkinson’s.

The sensor’s performance was considered comparable with the gold standard method (a kit used by clinical analysis laboratories).

“Integration of electronic chemical sensors with portable devices enables continuous, remote, real-time monitoring of patients’ key vital signs, metabolite levels and biomarkers to support health and well-being,” said Paulo Augusto Raymundo-Pereira, a researcher at the São Carlos Institute of Physics (IFSC-USP). “We want our device to be used to provide information on the patient’s state of health at the molecular level, paving the way for all kinds of personalized monitoring, decentralized analysis, and diagnostic and therapeutic applications. This potential was clearly demonstrated by the popularization of COVID-19 self-test kits during the pandemic.”

Focus on sustainability

Another important point about the sensor is that while existing portable electronic devices of the same kind are made of conventional plastic derived from petroleum, this one uses a biodegradable film made of polylactic acid (PLA) and thus helps meet the 17 Sustainable Development Goals (SDGs) adopted by all United Nations member states as part of Agenda 2030.

“PLA is a biodegradable, recyclable, compostable biobased polyester derived from lactic acid and made from renewable natural resources via fermentation of polysaccharides or sugars extracted from corn, wheat, potato, sugarcane, sugar beet or rice,” Raymundo-Pereira explained. “We chose it for its desirable intrinsic characteristics, including its chemical, physical, mechanical and thermal properties, high strength, elasticity and stiffness.”

In the United States, the material has been approved by the Food and Drug Administration (FDA) for biomedical applications such as stents, orthopedic plates and screws, absorbable sutures, drug delivery vehicles, adhesion prevention films, tissue engineering scaffolds, and other absorbable implantable devices or coatings in direct contact with biological fluids.

“As far as we know, the PLA bioplastic had never before been used as a substrate or support for disposable sensors and biosensors. Our article describes the first sustainable sensor strip integrated with a portable wireless analyzer for rapid self-testing,” Raymundo-Pereira said.

The article “Flexible and sustainable printed sensor strips for on-site, fast decentralized self-testing of urinary biomarkers integrated with a portable wireless analyzer” is at: www.sciencedirect.com/science/article/pii/S1385894723035064.