Figure 5
From: A novel dengue virus detection method that couples DNAzyme and gold nanoparticle approaches
Determination of optimal NaCl and SDS concentrations. A) The optimal concentration of sodium, in the form of NaCl, for aggregation of DDZ-M-AuNP following interaction with the DENV-2 RNA genome was determined. DENV -2 NGC strain genomic RNAs were isolated as described in Materials and Methods and 0.6 μM was incubated in a reaction mix containing DDZ-M-AuNP (1 × 105 particles/mL), 10 mM MgCl2, and increasing concentrations of NaCl (0 to 2 M) for 30 minutes at 37°C. A representative photograph of the reaction tubes is shown. The concentration of NaCl is indicated above each reaction tube. A full red to clear color transition indicates the optimum detection of the DENV-2 NGC genome. 1.5 M NaCl was determined to be the minimal optimum concentration of NaCl to use in our DENV detection reactions. B) The optimal concentration of SDS was determined in the presence of DENV-2 NGC virions. C6/36 cells were infected with DENV-2-NGC (MOI = 0.1). At 6dpi, 10 μl of cell supernatants containing 1 × 106 DENV-2 NGC/mL, as determined by TCID50-IFA, were added to a reaction mix containing 10 mM MgCl2, 1 × 105 DDZ-M-AuNP particles/mL, 1.5 M NaCl, and 0% (w/v) to 1% (w/v) SDS detergent. Samples were incubated at 37°C for 30 minutes and photographs were taken. Results demonstrate that the DDZ-M-AuNP colorimetric method for DENV detection occurs optimally in 0.5% SDS. The percent SDS used is indicated above each eppendorff tube. SDS = sodium dodecyl sulfate.