Excitability in chemical and biochemical pH-autocatalytic systems

Excitable dynamics in the bromate–sulfite–ferrocyanide reaction

“…Excitability in flow-through reactors has been largely studied by employing the Belousov-Zhabotinsky (BZ) reaction with the prime purpose of understanding the dynamics of an excitable system under periodic perturbations [1][2][3] and how the excitations are propagated through a cascade of CSTRs coupled by mass [4][5][6][7][8] or electrically. 9,10 Apart from the BZ reaction, many other chemical oscillators are also capable of displaying excitability which may occur in at least two different modes, activatory and inhibitory excitability, 11 and a systematic study of their properties is of interest. Here we have chosen the bromate-sulfite-ferrocyanide (BSF) system as an example of a pH-autocatalytic system.…”

Fronts and pulses in an enzymatic reaction catalyzed by glucose oxidase

“…A propagating pulse in a spatially extended system should be related to excitability in a point (0D) or well stirred system, where a superthreshold perturbation results in a large amplitude excursion before the system returns to its initial stable SS. Many models possessing pH bistability and oscillations also exhibit excitability (29)(30)(31). The region of excitability is often located near the Hopf bifurcation that leads to oscillations or near the saddle-node bifurcation that results in bistability (32,33).…”

“…2c tends to a plateau, also as a result of Eq. 10, which slows the autocatalytic production of h. The buffering properties of the enzyme have been discussed in detail elsewhere (30). The dependence of v on D h in Fig.…”

“…Here, instead, we consider a more general ''activator-depleted substrate'' model of pulse propagation. We analyze the following set of equations (30).…”

Light-Triggered Soft Artificial Muscles: Molecular-Level Amplification of Actuation Control Signals

“…Although most subsequent research in this area has employed the Belousov−Zhabotinsky (BZ) reaction 27 , there has been use of other systems including work by Horváth with the Landolt system 28 . Here we harness excitability 29 , 30 , another property of such autocatalytic reactions but one which has not been applied to the actuation of hydrogels. While light has been used both to modulate oscillations from nonlinear reactions in the past 31 , 32 , and as the sole source of pH change for hydrogel actuation 33 – 35 , the opportunity to apply light merely as the low energy trigger for an excitation and resulting high energy pH-induced actuation has not yet been reported.…”