Spotting biomarkers of pulmonary tuberculosis in human exhaled breath using porphyrin based sensor array.

Abstract

In search of a rapid point-of-care diagnostic tool for the diagnosis of pulmonary tuberculosis (P-TB) this exhaled breath analysis study was conducted using porphyrin based sensor. A single total exhaled breath test was done on 62 participants, 32 P-TB cases and 30 healthy controls using sensor plate comprising of 24 coded porphyrin elements; Red, Green and Blue (RGB) analysis was done pre and post exposure. Different porphyrin derivatives exhibited varied RGB responses. Seven analytes in our sensor array showed notifiable responses to differentiate diseased from healthy in accuracy parameters: sensitivity was finest in three IB, IIBa, ICh, then IAb and ICd; in specificity ICa was best; Fair positive predictive value was in ICa, IIBa, ICd, I, IAb, ICh; likelihood ratio was not encouraging. ICa, IIBa, IB, IAb demonstrated fairly strong post-exposure chromatic changes in binary logistic regression. In our study, porphyrin array-based chemical sensing showed promising results for the direct diagnosis of pulmonary tuberculosis. The quality of interaction with organic volatile compounds can be controlled by suitable changes in the porphyrin macrocycle like peripheral substituent and central metal. This would lead to fine tuning of senor array by identifying responsive porphyrin derivatives with better predictive value and incorporation them in a single array for enhanced responses. It would be worth evaluating colorimetric porphyrin elements based sensor array in more detail as a likely cost-effective futuristic model of non-invasive entrant in diagnostic algorithms to halt the pandemic of tuberculosis.