@article{scholars10755,
            year = {2018},
         journal = {Nanoscale Research Letters},
           title = {Red Spectral Shift in Sensitive Colorimetric Detection of Tuberculosis by ESAT-6 Antigen-Antibody Complex: a New Strategy with Gold Nanoparticle},
       publisher = {Springer New York LLC},
             doi = {10.1186/s11671-018-2753-5},
          volume = {13},
            note = {cited By 22},
             url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055318772&doi=10.1186\%2fs11671-018-2753-5&partnerID=40&md5=397d1bac395fb9a050a0db8ca6203cb1},
        keywords = {Antibodies; Antigens; Color; Colorimetry; Disease control; Gold nanoparticles; Metal nanoparticles; Tubes (components), Antibody concentration; Antigen-antibody complex; Bacterial pathogens; Colorimetric assays; Colorimetric detection; Mycobacterium tuberculosis; Salt-induced aggregation; Tuberculosis, Chemical detection},
        abstract = {Tuberculosis (TB) is a highly contagious life-threatening disease caused by the bacterial pathogen Mycobacterium tuberculosis. ESAT-6, an abundant early secretory antigenic target protein by M. tuberculosis, found to play a vital role in virulence. Developing a friendly method for the detection of ESAT-6 at the lower concentration facilitates to treat TB at an earlier stage and helps to control the spreading of disease. Herein, a new single-step approach was designed and was done by pre-mixing ESAT-6 and antibody before being added to the gold nanoparticle (GNP) followed by the salt-induced aggregation. We could attain the detection limit of 1.25{\^A} pM, showing the aggregation of GNP and the red spectral shift. Further, a higher specificity was demonstrated with the lack of electrostatic biofouling by ESAT-6 on GNP and retained the dispersed GNP in the presence of 10-kDa culture filtrate protein from M. tuberculosis. The required precise antibody concentration for this assay was found to be 60{\^A} nM. The increment in the antibody concentration from 75{\^A} nM drastically diminishes the sensitivity to {\texttt{\char126}} 680-fold, due to the crowding effect. With this assay, we attested the suitability of colorimetric assay for efficiently detecting the smaller-sized protein. {\^A}{\copyright} 2018, The Author(s).},
            issn = {19317573},
          author = {Wang, F.-A. and Lakshmipriya, T. and Gopinath, S. C. B.}
}