Researchers at the University of São Paulo (USP) in Brazil have developed a portable sensor made of simple materials that can detect heavy metals in sweat.
“We get important information on a person’s health by measuring their exposure to heavy metals,” said said Paulo Augusto Raymundo Pereira, last author of the article and a researcher at IFSC-USP. “High levels of cadmium can lead to fatal problems in the airways, liver and kidneys. Lead poisoning damages the central nervous system and causes irritability, cognitive impairment, fatigue, infertility, high blood pressure in adults and delayed growth and development in children.”
Unlike other tests to detect heavy metals in biofluids, the sensor is simple. According to the paper published in Chemosensors, the base of the device is polyethylene terephthalate (PET), on top of which is a conductive flexible copper adhesive tape with the sensor printed on it, and a protective layer of nail varnish or spray. The exposed copper is removed by immersion in ferric chloride solution for 20 minutes, followed by washing in distilled water to promote the necessary corrosion. The device is connected to a potentiostat, a portable instrument that determines the concentration of each metal by measuring differences in potential and current between electrodes.
The system is simple enough to be used by non-specialists without training, as well as technicians in such locations as hospitals, clinics and doctor’s offices. The device can also be used in several types of environmental management situation.
The sensor’s performance in detecting lead and cadmium was assessed in trials using artificial sweat enriched under ideal experimental conditions. The team says adaptations are required before the device can be patented.
“Until the invention was finalized, we found no reports of flexible copper sensors being used to detect toxic metals in sweat, but an anteriority search would probably turn up something similar, potentially blocking a patent application,” said Marcelo Calegaro, co-author of the article and a researcher at IQSC-USP.
To avoid this problem, the team is working on refinements and additional applications. One idea would entail replacing the corrosion stage, which produces waste, by cutting in a paper machine. Another would be to use the same type of device to detect pesticides in water and food.