Bioelectronic Processes

Aoyagi, T. Tsuyuki, T. Takahashi, and R. Stevenson, Tetrahedron Lett. 3397 (1972). 

In luciferin bioluminescence, the most extensively studied system, the substrate luciferin (49) becomes oxygenated by molecular oxygen with the help of the luciferase to afford the intermediary a-peroxylactone.74 On decarboxylation an electronically excited carbonyl product is obtained which is photodeactivated with light emission, as illustrated in Eq. (28) for the firefly luciferin (49a), affording the oxyluciferin (50) via a- 

Oxygen-18 labeling experiments provide mechanistic confirmation for the intervention of a-peroxylactones (2) in luciferin bioluminescence. The first such experiment was performed by DeLuca and Dempsey.77 It was concluded that no a-peroxylactone intermediate was involved in firefly bioluminescence. Instead of the cyclic peroxide path [Eq. (29a)], the tetrahedral intermediate path [Eq. (29b)] was postulated. However, White and co-workers7 observed that in the chemical oxygenation the 

Several examples have recently been documented by Cilento and coworkers.83 Thus, in the chemical autoxidation of 4-hydroxy-3,5-diiodophenylpyruvic acid (51) electronically excited 4-hydroxy-3,5-diiodobenzaldehyde (52) is formed, since its chemiluminescence could be detected.83 Presumably the dioxetane (lau) intervenes Eq. (31)]. 

Since this process is involved in thyroxine biosynthesis,14 it is likely that the enzymic oxygenation also involves dioxetanes. The horseradish peroxidase (HRP)-catalyzed oxygenation of indole-3-acetic acid (53) affords electronically excited indole-3-aldehyde (54).83b The a-peroxylactone (2j) was postulated to be responsible for the feeble light 

---

Lancy ME (1984) Phonon-Electron Coupling as a Possible Transducing Mechanism in Bioelectronic Process Involving Neuromelanin. J Theor Biol 111 201... 

The electrical contact of redox proteins is one of the most fundamental concepts of bioelectronics. Redox proteins usually lack direct electrical communication with electrodes. This can be explained by the Marcus theory16 that formulates the electron transfer (ET) rate, ket, between a donor-acceptor pair (Eq. 12.1), where d0 and d are the van der Waals and actual distances separating the donor-acceptor pair, respectively, and AG° and X correspond to the free energy change and the reorganization enery accompanying the electron transfer process, respectively. 

Reprinted from Biosensors and bioelectronics, 17(6-7), Henke L, Nagy N, Krull UJ, An AFM determination of the effects on surface roughness caused by cleaning of fused silica and glass substrates in the process of optical biosensor preparation, 547-551, 2002, with permission from Elsevier. 

Meng, Z. Yamazaki, T. Sode, K., A molecularly imprinted catalyst designed by a computational approach in catalysing a transesterification process, Biosens. Bioelectron. 2004, 20, 1068-1075... 

Interest in these studies arises from fundamental research where monolayers serve as models of biomimetic systems, as well as from important apphcations of such systems in molecular and bioelectronic devices, in sensors construchons, corrosion/inhibition phenomena, and synthesis of nanostructures ]93]. Although self-assembly processes of sulfur-containing compounds occur at the surfaces of many metals, especially the copper-group metals (Cu, Ag, Au), the most extensive studies have been... 

Another important broadening of the reconstitution process is in the area of de novo synthesized proteins. The present study has demonstrated the feasibility of organizing bioelectronic systems based on reconstituted de novo proteins (Cf. Section 2.4). These examples spark the future possibilities in the field. By the reconstitution of new electroactive synthetic cofactors into pre-designed de novo proteins, new man-made bioelectrocatalysts may be envisaged. 

The final chapter presents some exciting aspects of the future of biosensors, such as internal signal processing in the biocomponent of the sensor aiming at bioelectronic principles, and the possibility of tailoring the proteins for specific sensor configurations. The practical developments of these and other possible applications will require the concerted effort of researchers from many disciplines. 

Liu J., Olsson G., and Mattiasson B., Short-term BOD (BODst) as a parameter for online monitoring of biological treatment process Part 1. A novel design of BOD biosensor for easy renewal of bio-receptor. Biosens. Bioelectron., 20, 562-570, 2004. 

Yasmin, Z., Khachatryan, E., Lee, Y.-H., Maswadi, S., Glickman, R., Nash, Ki., 2015. In vitro monitoring of oxidative processes with self-aggregating gold nanoparticles using all-optical photoacoustic spectroscopy. Biosens. Bioelectron. 64, 676—682. 

Figure 13.18 Schematic illustration of the electrochemical DNA sensor construction process. Reprinted with permission from Biosensors and Bioelectronics, VoL 51, p. 201-207, 2014. Permission awaited from Copyright 2014, Elsevier [172].

A new class of microwires can be assembled by dielectrophoresis from suspensions of metallic nanoparticles. The wires are formed in the gaps between planar electrodes and can grow faster than 50 pm per second to lengths exceeding 5 mm. They have good ohmic conductance and automatically form electrical connections to conductive islands or particles. The thickness and the fractal dimensicai of the wires can be controlled, and composite wires with a metallic core surrounded by a latex shell can be assembled. The simple assembly process and their high surface-to-volume ratio make these structures promising for wet electronic and bioelectronic circuits. 

Bioelectronics the incorporation of biological materials into electronic devices, e. g. Enzfets (see Field effect transitors). See Biosensor. The term is also used in a general sense for the application of electronics to the investigation of biological processes. 

In the bioelectronic nose, the vials will isolate populations of neurons that display different odorant receptors on their membrane surfaces, so that the electrical signals coming from the various vials can be associated with particular molecular features. The lids will be used during the cell-loading process to ensure that only the desired vial receives a particular cell type. If these cells are very motile when cultured, as neurons tend to be, the lids will also be needed to prevent them from crawling out of the vials. Confinement by the lids is also anticipated to be necessary in other applications, such as those using nonadherent cells from the immune system. 

---