SERS detection of pyrazinamide-resistant tuberculosis using gold nanowell arrays

GASTÓN MAGI; DANA CIALLA-MAY; DIEGO PALLAROLA

Conferencia; #LatinXChem Twitter Conference; 2020

Tuberculosis (TB) continues to be one of the main causes of illness and death in the world, mainly due to the existing limitations in the methodologies of diagnosis, prevention and treatment. Pyrazinamide (PZA) is the most effective drug against latent TB infection and the emergence of strains resistant to PZA represents a major public health problem. Pyrazinoic acid (POA) has been shown to be a biomarker of susceptibility to PZA, which means that the absence of POA is evidence of resistance. A simple and effective diagnostic test with high sensitivity and specificity, low cost and execution time is not yet available. Nanostructured materials are a promising tool for the development of low-cost platforms for the detection and identification of these markers, since they offer the possibility of miniaturization, monitoring of multiple species, and high molecular specificity. This work presents the manufacture of gold nanowells and their use as Raman scattering amplifiers for the detection of POA. The fabrication of SERS substrates consists of the deposition of a nanometric gold film on an anodized aluminum oxide substrate. This process is simple, low cost and highly reproducible. SERS spectra were obtained at different concentrations of POA in water, with a detection limit of 88 μM, showing a linear dependence in the range of concentrations relevant for the diagnosis of MTB resistant to PZA. On the other hand, the gold nanowells proved to be effective in detecting POA in the presence of PZA, which represents a remarkable aspect considering the molecular similarity between POA and PZA. These results provide a simple and promising approach for the detection and quantification of low molecular weight molecules at low concentrations in various fields of application.