Diagnosis of paediatric tuberculosis by optically detecting two virulence factors on extracellular vesicles in blood samples

Abstract

Sensitive and specific blood-based assays for the detection of pulmonary and extrapulmonary tuberculosis would reduce mortality associated with missed diagnoses, particularly in children. Here we report a nanoparticle-enhanced immunoassay read by dark-field microscopy that detects two Mycobacterium tuberculosis virulence factors (the glycolipid lipoarabinomannan and its carrier protein) on the surface of circulating extracellular vesicles. In a cohort study of 147 hospitalized and severely immunosuppressed children living with HIV, the assay detected 58 of the 78 (74%) cases of paediatric tuberculosis, 48 of the 66 (73%) cases that were missed by microbiological assays, and 8 out of 10 (80%) cases undiagnosed during the study. It also distinguished tuberculosis from latent-tuberculosis infections in non-human primates. We adapted the assay to make it portable and operable by a smartphone. With further development, the assay may facilitate the detection of tuberculosis at the point of care, particularly in resource-limited settings.

Spotlight on mycobacterial lipid exploitation using nanotechnology for diagnosis, vaccines, and treatments

“… 130 For their part, Zheng et al identified the presence of LAM in the surface of extracellular vesicles (EVs) released from bacteria during active TB, then used conventional EV-recovery techniques to obtain concentrated samples where conventional assays were performed with great sensitivity results. 131 …”

Extracellular Vesicles: Techniques and Biomedical Applications Related to Single Vesicle Analysis

“…In addition, it can provide higher-resolution images, which shows potential for simple, rapid, and efficient visualization of nanomaterials. 92,93 Currently, a microimaging measurement platform for particle immunoelectrophoresis on a chip has been reported, which was built by combining microcapillary electrophoresis (μCE) with dark-field microscopy. 94,95 EVs collected from either the culture supernatant of human breast cancer cells or the blood of a mouse breast cancer model were subjected to electrophoresis experiments.…”

“…This allowed for operation via a smartphone and thus be capable of detecting tuberculosis at the point of care. 93 The development of SEV analysis techniques will undoubtedly improve the understanding of pathogen physiology and thus facilitate the development of new diagnostic and treatment methods for infections. Ulcerative Colitis (UC).…”

Plasmonic Scattering Microscopy for Label‐Free Imaging of Molecular Binding Kinetics: From Single Molecules to Single Cells

“…Therefore, exosome analysis is a promising way to evaluate the health conditions from body liquid without biopsying tissues. [51][52][53] Traditional exosome biomarker analysis relies on the western blot technique, which requires laborious post-labelling processes for detection, making it impractical for rapid detection. Besides, western blot detection cannot analyze the size information of the exosomes, which is usually determined with an additional nanoparticle tracking analysis measurement.…”