Senior study author Tony Hu, PhD, Weatherhead Presidential Chair in Biotechnology Innovation at Tulane, is working with colleagues to streamline the new TB test so it can be performed in the community and read with a smartphone. Credit: Paula Burch Celentano
Nearly a quarter of a million children under the age of 15 die from tuberculosis each year; of these fatal TB cases, about 96% were not diagnosed in time to be treated. One of the difficulties with diagnosing TB in young children is that biomarkers of the disease may be present in low concentrations and may be masked by other components in typical respiratory samples. Researchers from Tulane University have now developed a blood test that can enhance the detection of pediatric tuberculosis, combining dark-field microscopy, nanotechnology and artificial intelligence to improve identification of disease biomarkers even at low concentrations.
The new method uses antibody-coated nanoparticles to target the glycolipid lipoarabinomannan (LAM) and the protein LprG, which can be found on extracellular vesicles in the blood of TB patients. This nanoparticle-enhanced immunoassay is based on gold nanorod (AuNR) probes and read by low-magnification dark-field microscopy. The use of low magnification removes the need for manual focusing and allows the process to be automated. The researchers established an automated workflow in which images are captured and then processed through an AI algorithm that reduces background noise and aids in the measurement of AuNR signals.
The team used their nanoparticle-enhanced immunoassay workflow to test samples from nearly 150 children living with HIV, who are at a high risk for severe illness or death from TB. The assay accurately detected TB in 89% of children who were confirmed to have TB via other methods such as bacterial culture and chest radiograph. Additionally, the test identified an additional 74% of children with unconfirmed TB that standard tests had missed. This study was published in Nature Biomedical Engineering.
“These initial results are quite promising for the diagnosis of pediatric TB using small volumes of blood, including among children missed by our typical sputum-based tests. The biomarker levels also went down after starting treatment, highlighting the test’s potential as a way to monitor the response to treatment,” said study co-author Sylvia M. LaCourse.
While the assay currently requires the use of sophisticated laboratory equipment, the team is working to streamline the test so it could be performed at the point of care in resource-limited communities, with results read by a smartphone, said senior author Tony Hu.