Blog

Portable biosensor made from recycled materials enables rapid covid-19 detection

The biosensor, made from recyclable graphite and plastic, can be operated manually without the need for specialized laboratories

 27/06/2025 - Publicado há 9 meses

By: Rui Sintra*

Art by: Daniela Gonçalves**

A imagem mostra o coronavírus estilizado em azul, com a proteína spike em vermelho. O fundo está em azul, com alguns coronavírus em tamanhos menores ao longo de toda a imagem
The sensor showed 95% accuracy, similar to RT-PCR, considered the gold standard in molecular diagnosis Photo: Freepik

A platform developed using recycled materials, sustainable technology, and low-cost production has been created by researchers at USP’s São Carlos campus. The biosensor is capable of detecting the covid-19 virus with 95% accuracy. It can be operated manually, without the need for laboratories or specialized infrastructure, and delivers results within minutes.

Manufactured with graphite recovered from recycled batteries and plastic from disposable cups, the device is a portable electrochemical-magnetic platform, which allows an accessible molecular diagnosis, representing an innovation of global impact, combining materials science, engineering, sustainability and public health. The work is described in an article in the scientific journal ACS Sensors.

The biosensor was developed as part of the project Towards the Convergence of Technologies: From Sensors and Biosensors to Information Visualization and Machine Learning for Data Analysis in Clinical Diagnosis, coordinated by professor Osvaldo Novais de Oliveira Junior from USP’s São Carlos Institute of Physics (IFSC). The initiative is supported by the São Paulo Research Foundation (Fapesp) and involves researchers from both IFSC and USP’s São Carlos Institute of Chemistry (IQSC). The device operates using magnetic nanoparticles functionalized with antibodies, which capture viral biomarkers in saliva samples. This interaction generates an electrochemical signal, read by a portable, handheld device.

The cost per unit is only 20 cents on the dollar, a fraction of the price of conventional exams. In the case of sars-cov-2, the sensor showed 95% accuracy, similar to RT-PCR, considered the gold standard in molecular diagnosis. The system was validated in saliva samples of patients with different age groups and genders, with confirmation by RT-PCR, ensuring its effectiveness in real clinical conditions.

Esquema mostra como é feito o teste. Acima, à esquerda, está um ícone de cabeça e pescoço em azul, com uma seta que mostra um tubo com saliva. Ao lado, a amostra de saliva é ampliada e mostra vários vírus. Abaixo, à esquerda, ha uma seta em azul , mostrando a saliva em um material portátil redondo branco.
Biosensor uses magnetic nanoparticles functionalized with antibodies, which capture viral biomarkers in saliva samples, generating an electrochemical signal read by a handheld device - Image: Article Reproduction

Universal platform

“The sensor is a universal platform. Although the first test was for COVID-19, it can be adapted for the rapid detection of other viruses, such as influenza,” explains Professor Frank Crespilho, from IQSC. He also served as coordinator of the Network for Research in Metabolomics and Diagnosis of covid-19 (MeDiCo) – USP/Capes, coordinator of technological development, and corresponding author of the article published in the journal ACS Sensors. “Our goal is to democratize access to quality diagnostics through sustainable and low-cost solutions.”

The first author of the publication is researcher Caio Lenon Chaves Carvalho, a former postdoctoral fellow in the laboratory of the IFSC professor. Collaboration among interdisciplinary groups was key to integrating technological innovation with social and environmental impact.

Homem branco, cabelos curtos e escuros. Ele usa cavanhaque, um jaleco branco e uma camisa social por baixo do jaleco. Está sorrindo.
Frank Crespilho - Photo: IQSC/USP

“It was a long project, led by professor Crespilho’s group, which had renowned scientific colleagues and culminated in unprecedented results in the scientific literature,” says Oliveira Junior.

In addition to IQSC and IFSC, the project involved national and international partnerships, including USP’s Medical School (FMUSP), the Federal University of Piauí (UFPI), the University of Minho (Portugal), and the BCMaterials research center in Spain. More than just a response to the pandemic, this platform marks a new paradigm in accessible diagnostic devices, reusing technological waste and offering innovative solutions for vulnerable regions.

The initiative highlights the potential of integrating science, sustainability, and public policy to address social and health challenges. Check out the scientific article published on the research here.

*Adapted by Júlio Bernardes

English version: Nexus Traduções, edited by Denis Pacheco

Política de uso 
A reprodução de matérias e fotografias é livre mediante a citação do Jornal da USP e do autor. No caso dos arquivos de áudio, deverão constar dos créditos a Rádio USP e, em sendo explicitados, os autores. Para uso de arquivos de vídeo, esses créditos deverão mencionar a TV USP e, caso estejam explicitados, os autores. Fotos devem ser creditadas como USP Imagens e o nome do fotógrafo.