A team of researchers at the Nano Institute at the University of Utah (UT, USA) has developed a diagnostic assay that can detect tuberculosis (TB) infection at the early stages of the disease. The study, presented at IDWeek 2015 in October, utilized surface-enhanced Raman spectroscopy (SERS) to measure a marker of active TB infection in serum samples.
TB is second only to HIV/AIDS as the most deadly single infectious agent, and is a major worldwide health issue. However, TB is a treatable and curable disease if detected swiftly. The gold standard in diagnosing TB is by culture, but this process can take weeks, can be costly and requires correct biosafety infrastructure. Therefore, the development of a diagnostic platform that can be used in resourced-limited settings is a key area of scientific research.
The Nano Institute team investigated a disease detection system based on SERS technology with the aim of aiding the successful identification of infected individuals. They designed a SERS immunoassay to detect lipoarabinomannan (LAM) as a biomarker of active TB infection. LAM is present in serum at low concentrations during early stage infection, and the team believe that the SERS assay is a useful tool for measuring this.
Jennifer Granger, a research scientist from the Nano Institute of Utah who worked on the project, explained the utility of the SERS platform: “Our assay is very similar to ELISA, but we can get enhancement in our readout by taking advantage of SERS. It gives us the opportunity to develop unique labels on nanoparticles. When you bring them closer to the surface, you see an enhancement of those labels, which allows us to detect things at very low levels.”
The researchers conducted a proof of principle study with samples collected from a small cohort of patients with culture confirmed for TB. They found that LAM had a clinical sensitivity of 91% as a sole serum-based marker. From their initial results, the team believes the SERS platform could form the basis of a new diagnostic tool, capable of detecting markers of TB infection at levels below that of ELISA. As their next step, the Utah team will investigate LAM as a biomarker for TB in a larger cohort of patients.
Sources: Novel assay detects TB in early stages of disease; Granger J, Laurentius L, Crawford A et al. Early Detection of Tuberculosis: An Emerging Diagnostic Using Surface Enhanced Raman Scattering (SERS). Program and Abstracts of IDWeek 2015. San Diego, CA, USA, 7-11 October 2015 (Abstract 588).