Localized Deposition of Au Nanoparticles by Direct Electron Transfer through Cellobiose Dehydrogenase

Abstract

Cellobiose dehydrogenase (CDH) is a fascinating extracellular fungal enzyme that consists of two domains, one carrying a flavin adenine dinucleotide (FAD) and the other a cytochrome-type heme b group as cofactors. The two domains are interconnected by a linker and electrons can shuttle from the FAD to the heme group by intramolecular electron transfer. Electron transfer between CDH and an electrode can occur by direct electron transfer (DET) and by mediated electron transfer (MET). This characteristic makes CDH an interesting candidate for integration in systems such as biosensors and biofuel cells. Moreover, it makes CDH an alternative for the reduction of metal ions through DET and MET. In this work we have explored the localized deposition of gold on Pd substrates by CDH through DET and MET. For this purpose we exploited the advantage of scanning electrochemical microscopy (SECM) as a patterning tool. We first demonstrated that gold nanoparticles can be formed in homogenous solution. Then we showed that Au nanoparticles can also be locally formed and deposited on surfaces through DET at low pH and by MET at neutral pH using benzoquinone/hydroquinone as mediator.

Behavior of metal ions in bioelectrochemical systems: A review

“…Moreover, the related enzymes and endogenous electron mediators contributed to the changes of electron transfer reaction thermodynamics, especially for gold systems [194]. By means of enzyme electrochemical system, gold nanoparticles could be locally deposited on Pd substrates through direct and mediated electron transfer by cellobiose dehydrogenase that consisted of two electron transfer mediate domains [195].…”

Cellobiose dehydrogenase modified electrodes: advances by materials science and biochemical engineering

“…Such progress has prompted this new review on the bioelectrochemistry of CDH. One should also note that CDH has been used to make gold nanoparticles (AuNPs) and with the use of scanning electrochemical microscopy it was possible also to localise such AuNPs on surfaces with the help of CDH [59]. …”

Direct Electron Transfer between Glucose Oxidase and Gold Nanoparticles; When Size Matters

“…For example, Willner and co‐workers have shown that GOx can pump electrons directly to a confined metal particle and charge it . We demonstrated that the enzyme CDH catalyses the reduction of AuCl 4 − by DET from lactose in the presence of a catalytic metal surface, such as Pd, or AuNPs.…”

“…In a previous work, we explored the localized deposition of gold on Pd by CDH through DET . The localized bio‐catalyzed deposition of AuNPs by scanning electrochemical microscopy (SECM) was observed at pH 5.…”