Development of nanostructured Rapid Tests for differential detection of Tuberculosis and Pneumonia.

Abstract

Tuberculosis is an infectious disease that mainly affects the lungs and ranks among the leading causes of death worldwide. Brazil has a concerning trend of increasing numbers of infected individuals, and detecting the disease can be challenging due to nonspecific symptoms and limited diagnostic methods. Early diagnosis is essential for effective treatment of the disease, in order to avoid severe cases and the emergence of antibiotic-resistant strains. Thus, the use of specific biomarkers becomes relevant for the early and accurate diagnosis of tuberculosis and other pathologies with similar symptoms, such as pneumonia. Biosensors are analytical devices widely used in the medical and environmental industries, with a diversity of applications. Paper-based biosensors, in particular, stand out for their popularity due to their low cost and intrinsic portability. This project aims to develop a multiplex biosensor based on lateral flow capable of simultaneously detecting the pneumolysin biomarker of Streptococcus pneumoniae, the pathogen of pneumonia, and the Hsp65 protein of Mycobacterium tuberculosis, the bacterium that causes tuberculosis, in order to provide a practical, sensitive, and specific alternative for the differential diagnosis of these diseases. Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) will be used as colorimetric probes for each biomarker. The sample will be pre-incubated with functionalized conjugates with anti-Hsp65 antibodies (AuNPs-Ab) and anti-pneumolysin antibodies (AgNPs-Ab), and then applied to the initial layer of the device. By capillarity, the sample will flow to the detection region, where the test line modified with anti-Hsp65 and anti-pneumolysin antibodies, as well as the control line with secondary antibodies, are located. When the applied sample contains the target proteins, there will be a specific binding between antibody-protein-antibody on the test line of the device, which will indicate the diagnosis by its color, red for tuberculosis, yellow for pneumonia, or orange, positive for both diseases. Different experimental parameters will be evaluated. The research will have a significant impact on public health, especially in socioeconomically disadvantaged regions, where early and accurate identification of these diseases may be hindered by the lack of infrastructure and medical resources.