Assessment of metals in detection of TB biomarkers: Novel computational approach Rupashree S. Ray a , Biplab Sarma a , Swomitra Mohanty a, b , Keith Prisbrey a , Mano Misra a, b, * a Metallurgical Engineering, University of Utah, Salt Lake City, UT 84112, USA b Chemical Engineering, University of Utah, Salt Lake City, UT 84112, USA highlights graphical abstract  DFT calculations to identify suitable metal ion to be used for TB detection.  Proper methodology adopted to evaluate mono, di and trivalent metal ions.  Exploring fundamental mechanism of interaction of TB biomarkers with metal ions. article info Article history: Received 25 April 2014 Received in revised form 14 April 2015 Accepted 18 April 2015 Available online 16 May 2015 Keywords: Computational techniques Ab initio calculations Electronic structure Nanostructures DFT abstract Computational approach has been applied for the identification of suitable metal ions that can be functionalized on titania (TiO 2 ) nanotubes for possible application as a detection assembly for detecting different pathogenic conditions present in the human body such as tuberculosis. B3LYP Density func- tional calculations are performed to quantify the binding affinity of a set of metal ions of different valency such as: monovalent: Li 1þ , Cu 1þ , divalent: Fe 2þ , Ni 2þ , Cr 2þ , Co 2þ , Ca 2þ , Mg 2þ , Zn 2þ , Cu 2þ trivalent: In 3þ , Co 3þ , Fe 3þ , Al 3þ , Cr 3þ for the biomarker molecules such as methyl phenylacetate, methyl p-anisate, methyl nicotinate, and o-phenyl anisole that are responsible for the detection of tuberculosis. Also a quantitative analysis has been discussed by addressing the selectivity of metals towards the biomarkers in presence of volatile organic compounds commonly present in human breath. Present study shows that among the trivalent and divalent metal ions considered in this work, Al 3þ and Cu 2þ selectively shows a relatively higher binding affinity towards the above biomarker molecules in presence of volatile organic compounds. The result from this study can be used for the fabrication of sensing system (metal functionalized TiO 2 -nanotube) for the detection of tuberculosis which is currently undergoing in our research group. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Recently the analysis of volatile organic biomarkers (VOBs) in biological specimens has attracted a tremendous amount of clinical interest [1]. Prior investigation of VOBs has also indicated * Corresponding author. Metallurgical Engineering, University of Utah, Salt Lake City, UT 84112, USA. E-mail address: mano.misra@utah.edu (M. Misra). Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys http://dx.doi.org/10.1016/j.matchemphys.2015.04.018 0254-0584/© 2015 Elsevier B.V. All rights reserved. Materials Chemistry and Physics 161 (2015) 1e8