**3. Chiral-induced spin selectivity (CISS) effect for hybrid materials**

By the way, as a chirality phenomenon that can still cross the hierarchy, "chiralinduced spin selectivity (CISS)" proposed by Professor Ron Naaman is one of the most notable concepts at present [2]. The information gained through the experiment will be meaningful to the science, though this description is merely a "proposal" level.

As mentioned below, injecting electrons into oxidoreductase through oligopeptide which works as a spin filter is the first ever experiment, and it is crucial to cooperate with Dr. Naaman for this research. They believe several years of experience on metal complexes and profound knowledge about the CISS Dr. Naaman has can lead to a promising outcome. One of results they already expect to have is that if they detect the change of chiral property affected by the subtle transformation of metal complex and oligopeptide, they can observe and analyze the electrochemical change.

Their cooperative research covers the fields of the surface physics and the biochemistry, and their results of fixing the electron transfer pathway between electrode and enzyme, and of control of magnetism that metal complex has by the external magnetic field, would be applied to other fields. Also, the CISS effect will offer new possibilities for a better understanding of process of spin selection in the biology and spin electronics applications.

The injection of electrons into laccase using the CISS effect is the first trial of its kind. If this experiment was conducted successfully, the results would contribute to other fields including the spin electronics.

Then they were planning to apply the CISS effect to metal complex to magnetize spins from outside to control them while performing electrochemical measurement. The CISS effect is that in chiral molecules only spins which are orientated in a certain direction can be transferred smoothly. This effect has been studied a lot in recent years with Dr. Naaman, as the leading researcher. With Dr. Naaman's cooperation, who is the leading researcher of this effect, it is particularly noteworthy that difference in chirality shows different spin polarization, which suggests that this effect is applicable to a system where laccase is used (**Figure 2**).

Prepare a measuring device described, then inject spin polarized electrons into laccase where metal complex is present. Place oligopeptide and the metal complex between the electrode and the laccase. They use the oligopeptide and the metal complex, which let spin polarized electrons be transferred smoothly, so that the increase of amperage should be expected. They also analyzed how spin polarized electrons affect the way electron-transfer to the enzyme is occurred. As

**Figure 2.** *Proposed of measuring system for CISS effect of redox proteins (laccase).*

a preliminary experiment, they conducted electrochemical measurement using the above method without the metal complex. The result shows that the chirality of peptide affects the electron-transfer to the laccase. Following this outcome, they expect the follows. If they insert the metal complex between the oligopeptide and laccase, with the metal complex being fixed inside the hydrophobic pockets of laccase, the metal complex would be fastened firmly to the laccase. Then the electron-transfer to the Cu-T1, which proceeds oxygen reduction reaction, can be carried out selectively. In addition to that, they will examine how the electron-transfer would change when creating an external magnetic field, and they will also analyze it by comparing the use of ferromagnetic or photoresponsive metal complexes.

Some reports have been submitted regarding the injection of electron spins only into membrane protein or oligopeptide in those days, but there has not been any report on the injection of the electron spins into oxidoreductase. The results from the preliminary experiments suggest there is a possibility of realizing the electrontransfer without being influenced by the external magnetic field. Their idea has an intension of examining the electron-transfer in depths from a new perspective by injecting the electron spins into laccase using the CISS effect to elucidate the difference electrochemically between other mediate complexes. The analysis about behavior of the electrons will contribute to the development of biochemistry and a field of spintronics device.

Unfortunately, actual research using laccase only has not yet been published to date.

#### **4. Concluding remarks**

In this way, "chirality" may be found in many fields of natural sciences and technology potentially. The main purpose of this plan about the CISS effect study was just to improve electron transfer between the electrode and the enzyme in enzymatic biofuel cell using the CISS effect. Along with that, they are also planning to reveal from a spin-polarized point of view how magnetic field and chiral property affect the electron transfer reactions. Also, if we achieve the implementation of the CISS effect, the result would be applied "chirality" for other areas such as energy materials science and medical biochemistry.

**5**

**Author details**

Takashiro Akitsu

Tokyo, Japan

Department of Chemistry, Faculty of Science, Tokyo University of Science,

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: akitsu2@rs.tus.ac.jp

provided the original work is properly cited.

*Introductory Chapter: Chirality*

*DOI: http://dx.doi.org/10.5772/intechopen.98305*

*Introductory Chapter: Chirality DOI: http://dx.doi.org/10.5772/intechopen.98305*

*Current Topics in Chirality - From Chemistry to Biology*

*Proposed of measuring system for CISS effect of redox proteins (laccase).*

photoresponsive metal complexes.

field of spintronics device.

**4. Concluding remarks**

materials science and medical biochemistry.

to date.

**Figure 2.**

a preliminary experiment, they conducted electrochemical measurement using the above method without the metal complex. The result shows that the chirality of peptide affects the electron-transfer to the laccase. Following this outcome, they expect the follows. If they insert the metal complex between the oligopeptide and laccase, with the metal complex being fixed inside the hydrophobic pockets of laccase, the metal complex would be fastened firmly to the laccase. Then the electron-transfer to the Cu-T1, which proceeds oxygen reduction reaction, can be carried out selectively. In addition to that, they will examine how the electron-transfer would change when creating an external magnetic field, and they will also analyze it by comparing the use of ferromagnetic or

Some reports have been submitted regarding the injection of electron spins only into membrane protein or oligopeptide in those days, but there has not been any report on the injection of the electron spins into oxidoreductase. The results from the preliminary experiments suggest there is a possibility of realizing the electrontransfer without being influenced by the external magnetic field. Their idea has an intension of examining the electron-transfer in depths from a new perspective by injecting the electron spins into laccase using the CISS effect to elucidate the difference electrochemically between other mediate complexes. The analysis about behavior of the electrons will contribute to the development of biochemistry and a

Unfortunately, actual research using laccase only has not yet been published

In this way, "chirality" may be found in many fields of natural sciences and technology potentially. The main purpose of this plan about the CISS effect study was just to improve electron transfer between the electrode and the enzyme in enzymatic biofuel cell using the CISS effect. Along with that, they are also planning to reveal from a spin-polarized point of view how magnetic field and chiral property affect the electron transfer reactions. Also, if we achieve the implementation of the CISS effect, the result would be applied "chirality" for other areas such as energy

**4**
