Design and evaluation of a biofilm collection device for tuberculosis detection

Details

Supervisors

Kerckhofs, Greet ; Grobbelaar , Melanie

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical, à finalité spécialisée

Abstract

enTuberculosis (TB) remains one of the world's deadliest infectious diseases. Although effective treatments exist, it continues to affect more than 10.6 million people a year, and caused 1.6 million deaths in 2021. In many low-resource countries, insufficient access to diagnostic tests is a major contributor to delayed diagnosis and, consequently, to the persistence of high numbers of deaths and infections. Diagnostic tests are mainly based on sputum analysis, a method that is invasive, uncomfortable and difficult to perform for some patients. These constraints have motivated the exploration of alternative approaches, among which lingual biofilm swabbing stands out as a promising solution, as it is less invasive, simpler to perform, and more patient-friendly. Numerous swabs are commercially available, some with similar applications, such as those used during the COVID-19 crisis. However, a major problem persists, as the sensitivity of these tests remains insufficient, largely because their design has not been specifically studied for this application. This limits the quantity and quality of sampling, thereby reducing diagnostic efficiency. The aim of this work is to design a new type of swab, specifically optimized for the detection of pulmonary tuberculosis. This involves a swab that can efficiently reach bacteria-rich areas of the tongue, absorb a sufficient quantity, and then release the collected bacteria for analysis, while guaranteeing comfort, safety and ease of use. The project involved two major stages. The first concerned the overall design of the object, working on its shape, ergonomics and compatibility with oral anatomy. The aim was to ensure targeted access to lingual biofilm while facilitating autonomous use, particularly in low-resource contexts. The second stage focused on the absorbent element, a crucial part of the design. Three experiments were carried out for this purpose, using X-ray microfocused computed tomography (microCT). First, a structural analysis to compare the internal architectures of different commercial swabs. Then an evaluation of their absorption capacity using a fluid simulating lingual biofilm, and finally an extraction method to study retention. These tests enabled us to better understand the link between internal structure and both absorption and extraction performance. Although this work does not yet conclude with a definitive solution, several promising directions have been identified for improving the design of biofilm collection devices. Optimization possibilities have been identified, both in terms of overall structure and choice of absorbent materials. These elements form a basis for the future development of a more effective tool, offering a valid alternative to sputum sampling for tuberculosis diagnosis.