Electronic Characteristics of Bacteriorhodopsin

Validation of a time-variant electrical equivalent circuit for a dry bacteriorhodopsin sensor

“…1, nor any of the reported equivalent circuits can be used to calculate the component values for simulating the changes in photocurrent responses caused by illumination of the sensor. This is despite the fact that this change in the response has been reported in the literature [7], [17], [16] and in our previous studies [19], [20].…”

“…This early modeling was based on the presumption that the system is a linear timeinvariant system. However, it has been reported in the literature [7], [18], [16] and in our previous studies [19], [20] that the time constants of the photoelectric response vary in dry bR sensors depending on whether the sensors are under the effect of incident light or not.…”

“…Therefore, the measurement using the transimpedance amplifier can be assumed as a short-circuit. The membrane resistance RM has been reported to be over 10 , [7], [18]. Fig.…”

“…The related time constants presented in the paper are illustrated in Fig. 2 Recently, Wang et al [18], Walczak [7], and Miyazaki et al [16] have reported that the bR capacitance varies depending on the illumination of the bR sensor. Our previous measurements [19] found that the time constant varies and that it cannot be modeled by a linear time-invariant (LTI) model.…”

“…This protein has been under intensive research because it has been seen as an important biomolecule for biochemical and technology-oriented studies [2]. The popularity of bR as a research target can be explained by several favorable characteristics: a high quantum efficiency (0.65) [3], an ability to function and survive under extreme environmental stress [4]- [7], and a storage life of years [8]. Owing to its advantageous properties, various technical applications in optoelectronics and biosensing have been proposed, such as an imaging sensor [9]- [12], a protein-based memory [2], [13], and a bio-photoreceiver [14].…”