Concomitant synthesis of polyaniline and highly branched gold nanoparticles in the presence of DNA

The reduction of chloroauric acid using aniline adsorbed on DNA produces highly branched dendritic gold nanoparticles with concomitant formation of polyaniline (PANI) in contrast to the formation of spherical Au nanoparticles in the absence of DNA. The conformation of DNA remains intact in the process as evident from circular dichroism (CD) spectra. The UV–Vis spectrum exhibits a broad absorption peak at 520–900 nm, for a combined effect of the gold surface plasmon and π band to localized polaron band transition of DNA-doped PANI. Both the dendritic Au–PANI–DNA and the spherical Au–PANI systems emit two peaks for excitation with radiation of 300 nm and the intensity ratio of the emission and FRET peak is higher in the dendritic Au–PANI than that in the spherical Au–PANI system. The dc-conductivity values of spherical Au–PANI and dendritic Au–PANI–DNA systems are 1.2 × 10−10 and 1.7 × 10−8 S/cm at 30 °C, respectively.

Graphical abstractHighly branched gold nanoparticles by reduction of chloroauric acid using aniline with concomitant formation of polyaniline (PANI) in the presence of DNA exhibit interesting PL properties.Figure optionsDownload full-size imageDownload high-quality image (88 K)Download as PowerPoint slideResearch highlights► Dendritic gold nanoparticles using aniline and ds-DNA with PANI–DNA fibrillar network. ► Without DNA, both PANI and gold nanoparticles exhibit a spherical morphology. ► Intensity ratios of emission and FRET peak are higher in dendritic Au than spherical Au–PANI. ► Dc conductivity of dendritic Au system is two orders higher than that of the spherical system.