The bioconjugation of DNA with gold nanoparticles towards the spectrophotometric genosensing of pathogenic bacteria

Abstract

The investigation of important bio-molecular events such as expression of special genes has shown promise with the advent of nanotechnology. The robust absorbance and scattering characteristics of AuNPs in the visible light region render them perfect sensing probes for numerous bioassay expansions based on different optical responses. In this study, we developed a simple, sensitive and rapid technique for the detection of the L. pneumophila Mip gene by applying AuNPs capped by citrate. Therefore, a new substrate for the immobilization of DNA was prepared. The purpose of the present study is to determine L. pneumophila via a colorimetric method using AuNPs. Transmission electron microscopy and dynamic light scattering were used for characterizing the size distribution and morphology of the AuNPs. Also, UV-Vis spectrophotometry was performed in the wavelength range of 220–65 nm for detection in different stages. A novel part of this study is the bioconjugation of L. pneumophila pDNA with the newly synthesized AuNPs. For the first time, pDNA (5′-SH-TCGA TAC TCT CCC CGC CCC TT T TGTATCGACG-3′) was conjugated with AuNPs. Then, cDNA was used for hybridization. The results were evaluated via optical spectrophotometry (UV-Vis), and the results indicated that the proposed method is able to detect in 1 zM concentration. Our findings indicate that this method is not only very simple and cost-effective but also has acceptable sensitivity and selectivity. Moreover, the stability of the used platform measured in the spectral range of 220–650 nm for 48 h, showed suitable results.