DNA-Biofunctionalization of CTAC-Capped Gold Nanocubes

Abstract

Clinical diagnostics and disease control are fields that strongly depend on technologies for rapid, sensitive, and selective detection of biological or chemical analytes. Nanoparticles have become an integral part in various biomedical detection devices and nanotherapeutics. An increasing focus is laid on gold nanoparticles as they express less cytotoxicity, high stability, and hold unique optical properties with the ability of signal transduction of biological recognition events with enhanced analytical performance. Strong electromagnetic field enhancements can be found in close proximity to the nanoparticle that can be exploited to enhance signals for e.g., metal-enhanced fluorescence or Raman spectroscopy. Even stronger field enhancements can be achieved with sharp-edged nanoparticles, which are synthesized with the help of facet blocking agents, such as cetyltrimethylammonium bromide/chloride (CTAB/CTAC). However, chemical modification of the nanoparticle surface is necessary to reduce the particle’s cytotoxicity, stabilize it against aggregation, and to bioconjugate it with biomolecules to increase its biocompatibility and/or specificity for analytical applications. Here, a reliable two-step protocol following a ligand exchange with bis (p-sulfonatophenyl) phenyl phosphine (BSPP) as the intermediate capping-agent is demonstrated, which results in the reliable biofunctionalization of CTAC-capped gold nanocubes with thiol-modified DNA. The functionalized nanocubes have been characterized regarding their electric potential, plasmonic properties, and stability against high concentrations of NaCl and MgCl2.

Shape-Dependent Catalytic Activity of Gold and Bimetallic Nanoparticles in the Reduction of Methylene Blue by Sodium Borohydride

“…The gold nanocubes, on the other hand, showed a positive zeta potential of ζ = +49 mV. The positive charge of the gold nanocubes was caused by the coating with CTA + [86]. Likewise, the zeta potential of the nanorods (CTAB) and nanoprisms (CTAC) was ζ = +61 and ζ = +64 mV respectively.…”

Reactive Oxygen Species-Based Nanomaterials for Cancer Therapy

“…Gold nanoparticles (AuNPs) are widely used in ROS-based tumor therapeutics due to their high stability, unique optical properties, and biosafety (Ashraf et al, 2016 ; Rogowski et al, 2016 ; Ding et al, 2020 ; Slesiona et al, 2020 ). AuNPs can be used as a redox catalyzer to enhance electron transfer of various electroactive biological species, thereby increasing lipid peroxidation and ROS levels, and ultimately inducing DNA double-strand breaks and cell apoptosis.…”

Adaptation of a Bacterial Bioluminescent Assay to Monitor Bioeffects of Gold Nanoparticles

“…Modern developments in facile and high-yield methods have provided the impetus for an astounding increase in biological applications of nanoparticles (NPs) [ 5 , 6 , 7 , 8 ]. Whilst a variety of metals, such as silver and copper, are employed in industrial NP applications, gold is clinically utilized for its inert nature, biocompatibility, and propensity for biomolecular ligand immobilization [ 9 , 10 , 11 , 12 ]. These properties diversify the applicability of gold NPs to include radioprotection, bioimaging, biosensing, and drug delivery.…”