Research focus of AG Reissig
The aim of the research conducted in AG Reissig is to develop biomimetic optoelectronic devices, through the emulation of biological systems that have been optimized over centuries of evolution, or through the incorporation of biomolecules into artificial constructs which are optimized to support their native structure and structural changes upon external stimulation. Our focus is primarily on biological soft matter systems, where the components are mobile, and can adapt depending on the various inter- and intramolecular interactions with themselves, as well as with other components and interfaces. The guiding principle of this research is to develop a thorough mechanistic understanding through fundamental studies and by comparison to model synthetic systems, and is driven by a vision towards applications through the formation of real devices, whose performance is tested, compared and improved.
Within this field, the focus lies primarily on the following three themes:
1) Protein photodetectors
Microbial rhodopsins are a group of photoactive proteins often considered as the "eyes of microbes", as they are not only structurally similar to the light receptors in our eyes, but also undergo light-induced structural changes that can lead to signalling cascades within the microbes to lead them toward favourable territories, or to the production of energy. In 2015, we developed a prototype differential photodetector based on a photoactive rhodopsin film. The aim of this project is to increase the performance of such protein photodetectors, and to correlate their performance with the properties of the proteins under study.
see e.g. S. Dalgleish, L. Reissig, Y. Sudo, K. Awaga On-Tip Photodetection: A Simple and Universal Platform for Optoelectronic Screening Chemical Communications 51(91):16401-16404 2015 DOI:10.1039/c5cc06237c
L. Reissig, S. Dalgleish, K. Awaga A differential photodetector: Detecting light modulations using transient photocurrents AIP Advances 6(1):015306 2016 DOI:10.1063/1.4939921
On-Tip Photodetection using a Photoactive Protein Film
2) In operando ATR-FTIR spectroscopy
FTIR spectroscopy, a technique which is sensitive to the vibrations of particular chemical groups in complex molecules, is a powerful tool to study the structure and structural changes of macro-molecules/systems upon external stimuli. By performing in operando measurements combined with impedance spectroscopic analysis on our photodetector devices we aim to add to the understanding of the optoelectronic processes within the devices, as well as the influence of electric fields on the biomolecules themselves. Such studies would also shed light on the specific interactions at the various complex interfaces that exist within the devices.
see e.g. L. Reissig, T. Iwata, T. Kikukawa, M. Demura, N. Kamo, H. Kandori, Y. Sudo Influence of Halide Binding on the Hydrogen Bonding Network in the Active Site of Salinibacter Sensory Rhodopsin I Biochemistry 51(44):8802–8813 2012 DOI:10.1021/bi3009592
3) Artificial myelin figures and their use in photonic devices
Artificial myelin figures resemble, both in structure and properties, the myelin sheaths surrounding the nerve axon in a large number of vertebrates, which serve to improve neural signal strength, speed and energy efficiency. The strongly uniaxial signal conduction along the myelin axon, where the insulating bilayer sheaths shield signal transfer within the myelin from the conductive medium surrounding them, make them suitable targets for artificial "wires" through aqueous solutions. This project aims to exploit these structures in real devices and circuits, as well as contribute to the fundamental understading of myelin structures, and the phase behaviour of surfactants (lipids, blockcopolymers) far from equilibrium.
see e.g. L. Reissig, D.J. Fairhurst, J. Leng, M.E. Cates, A.R. Mount, S.U. Egelhaaf Three-Dimensional Structure and Growth of Myelins Langmuir 26(19):15192-9 2010 DOI:10.1021/la102726r