Fig. 2.

3D μPAD for detecting Middle East respiratory syndrome coronavirus (MERS-CoV), Mycobacterium tuberculosis (MTB), and human papillomavirus (HPV). (a) Schematic illustration representing pathogenic DNA detection by the color change from peptide nucleic acid (PNA)-induced AgNP aggregation, (b) design and operation of origami-type 3D μPAD, (c) real images of visible color transformation from the DNA of MERS-CoV, MTB, and HPV, and (d) color intensities according to concentrations of target DNA with the corresponding calibration plots for (i) MERS-CoV, (ii) MTB, and (iii) HPV. Reproduced from Refs. [50] with permission of ACS Publications.