Protein immobilisation on perpendicularly aligned gold tipped nanorod assemblies

Abstract

A multi component assembly consisting of the redox protein cytochrome c (cyt c) immobilised onto vertically aligned gold tipped semiconductor nanorods is described. Cyt c was 10 successfully immobilised using a thiol linker. A faradaic response demonstrated that the protein is electroactive in this ultra high density array. Fig. 1a and Fig. 1 b show high resolution scanning electron microscopy (HRSEM) and high resulution transmission electron microscopy (HRTEM) images of the inorganic component in the assembly. The SEM side view image (Fig. 1a) shows the vertically aligned nanorods which were 45 electophoretically deposited onto large 2 cm × 1 cm ITO coated glass substrates, (see ESI †, Fig. S1 and S2). Nanorods of 100 nm in length were obtained by controlled oriented attachement of as synthesised nanorods 35 nm in length. 7 The nanorods are bound to the substrate at the end facets and are 50 separated from each other (~ 2 nm) by interdigitated longchain octadecyl phosphonic acid ligands. The resulting perpendicularly aligned nanorods were spun cast with a solution of gold chloride to grow a single gold tip on each rod in the array (Fig. 1b and ESI †, Fig. S3). The procedure was optimized to form individual gold tips of 3 nm in size, on 60

Silver tip formation on colloidal CdSe nanorods by a facile phase transfer protocol

“…6C). The tipped rods adopted an orthogonal orientation with the CdSe component in contact with the substrate similar to Au-tipped CdSe structures reported by Zhao et al 17 and O'Sullivan et al 9,23 Brighter contrast due to Ag tips was also clearly visible on vertically aligned CdSe rods under a scanning electron microscope, Fig. 6D.…”

“…6,20,22 More recently, electron transfer via redox processes in a protein immobilised on metal tipped nanorod arrays was detected at a substrate demonstrating potential for sensor applications. 23 A facile route to Au tip formation has been achieved where the metal precursor either (AuCl 3 ) or more recently (AuCl) and a reducing agent are solubilized in the organic phase using surfactants. Control of the reaction time, temperature and light activation can tune the structure from double tipped (both ends) to single tip to enlarged single tip.…”

A facile method for the synthesis of Co-core Au-shell nanohybrid

“…Ryan and co-workers have already reported such an approach using semiconductor-gold hybrids where Cyt C proteins molecules were immobilized on Au via suitable ligands. 29 Co and Co-core Au-shell nanomaterials were characterized by UV-visible spectroscopy, fluorescence spectroscopy, high resolution transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The measurement of magnetic properties using VSM reveals the retention of superparamagnetic character for the core-shell.…”

The evaluation of Coulombic interaction in the oriented-attachment growth of colloidal nanorods

“…8 To calculate the activation energy of an OA growth, one needs to calculate both CI and vdW interactions between the attaching nanoparticle and the growing nanorod. [9][10][11][12][13] In this Communication, the mathematical derivation of an analytical expression of CI between a spherical nanoparticle and a cylindrical nanorod is presented, and the expression is then applied to evaluate the correlation between CI and the parameters associated with the OA growth, such as the separation of the attaching objects, aspect ratio (AR) of the NRs, and charge density, etc. Combining the analytical expression of the vdW interaction, we used the CI expression to evaluate the activation energy of the OA growth of 1D nanorods.…”