Colorimetric detection of HVA by self-assembly of Au nanorods with DNA double helices to give side-by-side and end-to-end structures

In this article we present the self-assembly of gold nanorods with DNA double helices into side-by-side and end-to-end structures by the addition of HVA (hepatitis A virus Vall7 polyprotein gene). Between every two gold nanorods, there is a distance of 10.2 nm which agrees with the length of DNA. By observing the change in color with the naked eye or UV-Vis spectral absorbance, HVA concentration can be quantitatively measured. The colorimetric detection has a linear relationship between the UV-Vis spectral absorbance and the concentration, with a detectable range of 0.05 pM to 35 pM. The standard deviation R-2 value was found to be >0.99. This method is simple, time economic and highly sensitive, and a lower limit of detection up to 0.05 pM HVA can be achieved with great selectivity.