in one hybrid catalyst. However, this will most likely require the development
of more elaborate synthetic methods and novel support materials.
By having access to large libraries of hybrids with wide variation of the
enzyme and metal NP components, it will be much easier to design new cascades
that have the potential to deliver elaborate products that are synthetically useful.
Unfortunately, many of the cascade reactions involving nanometal-enzyme hybrid
catalyst that has been reported so far have primarily been designed to just showcase
their dual catalytic functions. As a result, the products formed from such cascades
have often been quite simple and not really valuable from a synthetic point of view.
Moving forward, it would be exciting to see hybrid catalysts being applied in more
intricate cascades, which can enable access to more elaborate and synthetically
useful target molecules in a fashion that is reminiscent of how complex natural
products are sequentially assembled in Nature. Here, it is important to point out
that we chemists have the possibility to go beyond Nature in the future, as we are
privileged to have the vast chemistry of all the transition metals at our full disposal.
As have already been demonstrated with the hybrids developed for DKR of
amines, it is possible to create artificial metalloenzymes that display overall catalytic
functions that have no precedence in Nature [36]. From this perspective, it will
be highly interesting to follow the continued research in this area over the coming
decades and to see what complex organic compounds that could soon be synthesized, thanks to novel nanometal-enzyme hybrids.
3 Bioelectrocatalysis: An Exciting Arena
for Nanometal-Enzyme Hybrids
Within the field of electrocatalysis, there has been a recent increase in the interest
for nanometal-enzyme hybrids that can be used as electrodes in enzymatic
biofuel cells (EBCs). In the medicinal sciences, there is a considerable interest
for EBCs since they constitute promising power sources for microelectronic
systems such as actuators and sensors [57]. The electricity needed to power
such devices would be produced by the EBC through electrochemical reactions
that makes use of endogenous substrates within the users’ bodies as the fuels.
Here, the oxidation of different saccharides at the anode coupled to the reduction
of oxygen at the cathode has been explored as the main way to generate electricity
in vivo. Of the endogenous saccharides, glucose has become by far the one most
vividly studied since it is abundant in relatively high concentrations in several
different body fluids [6, 57]. In addition to glucose, bioanodes have also been
developed for other substrates, such as cholesterol [58], creatinine [59], ethanol
[60–62], fructose [63, 64], lactate [65, 66], pyruvate [65, 67], urea [68, 69], and
vitamin C [70].
However, it should be emphasized that the research in EBCs still have a long
way to go before these devices can be considered as a realistic substitute for batteries
254
O. Verho and J.-E. Bäckvall
of more elaborate synthetic methods and novel support materials.
By having access to large libraries of hybrids with wide variation of the
enzyme and metal NP components, it will be much easier to design new cascades
that have the potential to deliver elaborate products that are synthetically useful.
Unfortunately, many of the cascade reactions involving nanometal-enzyme hybrid
catalyst that has been reported so far have primarily been designed to just showcase
their dual catalytic functions. As a result, the products formed from such cascades
have often been quite simple and not really valuable from a synthetic point of view.
Moving forward, it would be exciting to see hybrid catalysts being applied in more
intricate cascades, which can enable access to more elaborate and synthetically
useful target molecules in a fashion that is reminiscent of how complex natural
products are sequentially assembled in Nature. Here, it is important to point out
that we chemists have the possibility to go beyond Nature in the future, as we are
privileged to have the vast chemistry of all the transition metals at our full disposal.
As have already been demonstrated with the hybrids developed for DKR of
amines, it is possible to create artificial metalloenzymes that display overall catalytic
functions that have no precedence in Nature [36]. From this perspective, it will
be highly interesting to follow the continued research in this area over the coming
decades and to see what complex organic compounds that could soon be synthesized, thanks to novel nanometal-enzyme hybrids.
3 Bioelectrocatalysis: An Exciting Arena
for Nanometal-Enzyme Hybrids
Within the field of electrocatalysis, there has been a recent increase in the interest
for nanometal-enzyme hybrids that can be used as electrodes in enzymatic
biofuel cells (EBCs). In the medicinal sciences, there is a considerable interest
for EBCs since they constitute promising power sources for microelectronic
systems such as actuators and sensors [57]. The electricity needed to power
such devices would be produced by the EBC through electrochemical reactions
that makes use of endogenous substrates within the users’ bodies as the fuels.
Here, the oxidation of different saccharides at the anode coupled to the reduction
of oxygen at the cathode has been explored as the main way to generate electricity
in vivo. Of the endogenous saccharides, glucose has become by far the one most
vividly studied since it is abundant in relatively high concentrations in several
different body fluids [6, 57]. In addition to glucose, bioanodes have also been
developed for other substrates, such as cholesterol [58], creatinine [59], ethanol
[60–62], fructose [63, 64], lactate [65, 66], pyruvate [65, 67], urea [68, 69], and
vitamin C [70].
However, it should be emphasized that the research in EBCs still have a long
way to go before these devices can be considered as a realistic substitute for batteries
254
O. Verho and J.-E. Bäckvall