Fig. 3

Visual observation of PNA-AuNP colorimetric assay in presence of negative and positive samples. Upper row is negative samples from left to right, 1 mismatched DNA target, 2 deleted DNA target, 3 FMDV, 4 BoHV, 5 P. multocida, 6 E. coli O157:H7, 7 M. bovis, 8 BLV, and 9–11 negative field samples. Lower row is positive samples from left to right, 1 BVDV-NADL; 2 BVDV-2, 3–8 positive field samples, and 9–13 archived isolates