István Molnár1,2, István Szalai2
1 Semmelweis University, School of PH.D. studies, Budapest
2 Eötvös Loránd University, Institute of Chemistry, Budapest
Introduction: Calcium ion plays an important role in biological systems as second messenger; calcium ion oscillations and patterns have been observed in several cases, for example in frog oocyte or isolated retina. Calcium ion oscillation can be induced by a pH oscillator and pH dependent complexation of the metal ion. In this way calcium ion waves and patterns can be investigated in chemical reaction diffusion systems.
Aims: In earlier studies we have generated calcium ion patterns in bromate – sulfite – ferrocyanide – calcium – ethylenediaminetatraacetate (BSF-CaEDTA) system; where the compexation equilibrium is driven by bromate – sulfite – ferrocyanide (BSF) pH oscillator. The dynamics of the original pH oscillator and the coupled system differ based on the experiments: the BSF-CaEDTA reaction-diffusion system shows not only oscillations but stationary like patterns. The aim of this work is to investigate the reason of this important difference.
Method: The spatiotemporal dinamics of the BSF-CaEDTA reaction diffusion system in an open one-side fed reactor (OSFR) is investigated by numerical simulations. We completed the previously used kinetic model with the protonation and complexation equilibriums of EDTA and calcium ion.
Results: The complexing agent influences the dynamic of the pH oscillator: it buffers the system and by reversible hydrogen ion binding slows down the diffusion rate of hydrogen ion. However, in an open reactor (CSTR) only the buffering effect can be observed, in a reaction - diffusion system (OSFR) the oscillation region is narrows by increasing the concentration of the complexing agent and after a critical value oscillations can not be observed.
Conclusion: The complexation equilibrium not only follows the constraint of the oscillatory reaction, but it also provides a feedback on its operation.
Doctoral School: Pharmaceutical Sciences
Program: Modern Trends in Pharmaceutical Scientific Research
Supervisor: István Szalai
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