Fig. 7. (A) A scheme illustrating colorimetric detection of DNA. (B) The kinetics of FAM-24-mer DNA and its duplex adsorption in MES and HEPES, pH 7. (C) Kinetics of color change of the sensing samples in the presence of various concentrations of the target DNA in MES buffer, pH 7. (D) Calibration curves of the detection in MES and HEPES buffers measured at 20 min after adding NaCl. Inset: a photograph of 4 nM AuNPs and 100 nM probe DNA with 0 nM or 60 nM target DNA in 5 mM MES or HEPES buffer after 20 min incubation with 100 mM NaCl, pH 7.
