The Ag nanoparticles and nanoclusters (AgNP, AgNC) have been widely used due to their multiple applications, for example, in catalysts for CO2 to CO electrochemical reduction, O2 reduction in fuel cells, interface design for plasmonic resonance experiments and H2O2 or glucose sensors. The chemical methods most used to obtain AgNP, reported in the literature are: borohydride reduction, the Tollens method or the sonication at high concentrations of AgNO3. One important disadvantage of these methods is the multiple steps required for electrode design, especially in carbon materials, and one of them is MWCNTs, used in some applications mentioned above. Electrodeposition has been reported in the preparation of metallic particles. In this chapter, we described the electropolishing method in the preparation of AgNP and AgNC supported on MWCNT film. An advantage of this proposed method is that it allows obtaining AgNP and AgNC in situ, supported on carbon matrices, ready to use as electrodes in different applications.
Part of the book: Silver Nanoparticles
The design of bioelectrochemical interfaces (BEI) is an interesting topic that recently demands attention. The synergy between biomolecules and chemical components is necessary to achieve high molecular selectivity and sensitivity for the development of biosensors, synthesis of different compounds, or catalytic processes. For most BEI, the charge transfer process occurs in environments with particular chemical conditions; modeling these environments is a challenging task and requires multidisciplinary efforts. These interfaces can be composed of biomolecules, such as proteins, DNA, or more complex systems like microorganisms. Oxidoreductases enzymes are good candidates, among others, due to their catalytic activities and structural characteristics. In BEI, enzymes are immobilized on conductive surfaces to improve charge transfer processes. Covalent immobilization is the most common method to prolong lifetime or modulate the detection process. However, it is necessary to implement new methodologies that allow the selection of the best candidates for a more efficient design. Homology modeling of oxidoreductases combined with Molecular Dynamics (MD) simulation methods are alternative and already routinely used tools to investigate the structure, dynamics, and thermodynamics of biological molecules. Our motivation is to show different techniques of molecular modeling (Homology Modeling, Gaussian accelerated molecular dynamics, directed adaptive molecular dynamics and electrostatic surface calculations), and using horseradish peroxidase as a model to understand the interactions between biomolecules and gold nanoclusters (as current collector). Additionally, we present our previous studies considering molecular simulations and we discuss recent advances in biomolecular simulations aimed at biosensor design.
Part of the book: Homology Molecular Modeling