Mineralization and optical characterization of copper oxide nanoparticles using a high aspect ratio bio-template

Abstract

Organized chains of copper oxide nanoparticles were synthesized, without palladium (Pd) activation, using the M13 filamentous virus as a biological template. The interaction of Cu precursor ions with the negatively charged viral coat proteins were studied with Fourier transform infrared spectroscopy, transmission electron microscopy, and energy dispersive x-ray spectroscopy. Discrete nanoparticles with an average diameter of 4.5 nm and narrow size distribution were closely spaced along the length of the high aspect ratio templates. The synthesized material was identified as a mixture of cubic Cu2O and monoclinic CuO. UV/Vis absorption measurements were completed and a direct optical band gap of 2.87 eV was determined using Tauc's method. This value was slightly larger than bulk, signaling quantum confinement effects within the templated materials.

Bacteriophage Engineering for Improved Copper Ion Binding

“…Zaman et al have reported on bio-templated mineralization of M13 phages displaying three Glu units on their major coat proteins. [26] In that study, M13 viruses were first incubated with Cu(II) solution resulting in phage bundle formation that was similarly observed in our study for wild-type fd phages (Figure 4). Formation of phage agglomerates have been previously demonstrated by various studies elsewhere due to the electrostatic interactions between negatively charged virus molecules and positively charged counterions.…”

“…Phage bundle formation has been previously published by various research groups elsewhere demonstrating the supramolecular virus assembly formation due to the electrostatic interactions between negatively charged phage filaments and positively charged counterions. [26][27][28] On the contrary, engineered H and HGFANVA phages were observed to form more elongated fibrous structures coated with some form of mineralized Cu particles implied by the white colored filaments (Figure 4, 10 12 vir mL −1 ). Interestingly, before Cu(II) exposure, H and HG-FANVA phages were observed as darker networking filaments similar to wild-type fd viruses (Figure 3).…”

“…Formation of phage agglomerates have been previously demonstrated by various studies elsewhere due to the electrostatic interactions between negatively charged virus molecules and positively charged counterions. [20,[26][27][28] Zaman et al induced the formation of copper oxide particles by applying a reducing agent after phage bundle formation triggered by Cu(II) incubation process. [26] However, in our study, Cu(II) binding peptide was observed to induce the reduction process alone without the presence of a reducing agent.…”

Untitled

“…The ultravioletvisible (UV-vis) absorption results of an aqueous solution of methylene blue checked in the presence of ZnO NPs at different time intervals. The absorption peak decreased gradually with the extension of the exposure times, indicating the photocatalytic degradation [36][37][38][39].…”

Emblica officinalis leaf extract mediated synthesis of zinc oxide nanoparticles for antibacterial and photocatalytic activities

“…The ultravioletvisible (UV-vis) absorption results of an aqueous solution of methylene blue checked in the presence of ZnO NPs at different time intervals. The absorption peak decreased gradually with the extension of the exposure times, indicating the photocatalytic degradation [36][37][38][39].…”