A promising new device for diagnosing tuberculosis in the “lost

Philadelphia, June 22, 2023 – According to the World Health Organization, there are approximately three million cases of undiagnosed tuberculosis (TB) annually globally, which are characterized as “missing millions”. In this cutting-edge study, scientists tested a diagnostic device using dielectrophoresis that holds promise for improving TB detection and treatment of patients in highly endemic and resource-poor areas. Bringing the diagnosis to the patients who need it most will help meet global targets to reduce the TB burden. The results appear in Journal of Molecular Diagnosticspublished by Elsevier.

A unique academic-industrial partnership between a team of TB researchers at St George’s University of London, the Institute of Infection and Immunity, and QuantuMDx, a UK-based medical technology company, presents an opportunity to prioritize the development of treatments that are cheap, fast and accurate. , and a portable TB diagnostic test to analyze sputum samples Mycobacterium tuberculosis (Mtb) of suspected TB patients.

Lead researcher Philip D. Butcher, PhD, St George’s, University of London, explains, “The global burden of TB is not improving. Although it is contagious, it is highly treatable. However, affordable diagnostics suitable for use at the point of care are needed to reach the ‘lost millions’. Our TB research group in St George’s has long appreciated the global imperative for better TB diagnosis, and we realized that new technology could provide answers. We see an opportunity by collaborating on a new chip-based technology using dielectrophoresis to selectively isolate Mtb bacilli from sputum samples.”

The researchers describe a prototype lab-on-a-chip microfluidic system called CAPTURE-XT® from QuantuMDx that can process dissolved sputum from patients with suspected TB, capture Mtb bacilli for visual analysis (in lieu of microscopy smears), and provide samples for confirmation. molecular by quantitative PCR (qPCR) and finally for genotypic drug susceptibility analysis. CAPTURE-XT® technology relies on the principle of dielectrophoresis – a rarely used technique that can be adapted to selectively attract or repel certain particles or cells based on their dielectric properties. In this case, the TB-causing Mtb bacteria are specifically captured and concentrated, while the other sputum contents are rinsed away.

After optimization using a panel of 50 characterized sputum samples, prototype performance was assessed by blind screening of 100 characterized sputum samples and a bio-bank provided by the Foundation for Innovative New Diagnostics (FIND).

The agreement with the culture diagnosis was 100% for smear negative samples and 87% for smear positive samples. From positive AFB samples, the concordance of high load samples is 100%. These results demonstrate the potential of the technology to provide a powerful sample preparation tool that can serve as a front end platform for enhanced molecular detection. This versatile tool can also be applied as a visual detection diagnostic, potentially related to bacterial identification for low-cost screening.

Jonathan O’Halloran, PhD, founder and Chief Executive Officer of QuantuMDx Group Ltd said, “CAPTURE-XT® technology is truly revolutionary and will impact a wide range of diseases from sepsis to oncology (circulating tumor cells). This application is in MTB is truly extraordinary because its extremely low cost and extremely high sensitivity will greatly increase equitable access to quality diagnostics for hundreds of millions of people. This chip-based technology exploits the physiological properties of TB bacteria to be collected specifically into devices so that small amounts can be visualized on chip electrodes and act as visual readouts to replace laboratory-based sputum/microscopic examination methods, which typically have low detection rates and require staff training. laboratory, with molecular-like sensitivity and at a lower cost. Moreover, when used as a front end to downstream cellular, protein and molecular device, the possibilities are virtually endless.”

Professor Butcher concluded, “Co-operation between University-based academic researchers and biotechnology industry scientists provides a way forward for developing new approaches to some of the world’s biggest healthcare challenges, such as TB. This new chip-based technology can provide diagnoses to patients who need them and also, with more accessible case finding, prevent further spread of the disease.”

Co-author Heather Murton, PhD, LEX Diagnostics, Melbourn, UK, and formerly of QuantuMDx Group Ltd, said, “Tuberculosis is one of the oldest challenges facing human health care. this technology has the potential to meet the expectations of a mobile TB diagnosis, and it is exciting to see that seemingly abstract principles of physics are successfully applied to neglected areas of the disease.”

TB is the 13th leading cause of death worldwide, and until COVID-19 was the leading cause of death from a single infectious disease – more than malaria and HIV. Globally it infects 10 million people and kills 1.4 million people every year, 230,000 of them are children.

Diagnostics with increased sensitivity and expanded drug susceptibility testing are also needed to address drug resistance and diagnose cases with a low bacterial burden.