Monitoring biological membrane-potential changes: A CI QM/MM study

Journal article
(Original article)

Publication Details

Author(s): Rusu CF, Lanig H, Othersen O, Kryschi C, Clark T
Journal: Journal of Physical Chemistry B
Publisher: American Chemical Society
Publication year: 2008
Volume: 112
Journal issue: 8
Pages range: 2445-2455
ISSN: 1520-6106
eISSN: 1520-5207
Language: English


In recent decades, new less-invasive, nonlinear optical methods have been proposed and optimized for monitoring fast physiological processes in biological cells. One of these methods allows the action potential (AP) in cardiomyocytes or neurons to be monitored by means of second-harmonic generation (SHG). We now present the first, to our knowledge, simulations of the dependency of the intensity of the second harmonic (/SHG) on variations of the transmembrane potential (TMP) in a cardiomyocyte during an action potential (AP). For this, an amphiphilic potential-sensitive styryl dye molecule with nonlinear optical properties was embedded in a dipalmitoylphosphatidylcholine (DPPC) bilayer, replacing one of the phospholipid molecules. External electrical fields with different strengths were applied across the membrane to simulate the AP of a heart-muscle cell. We used a combined classical/quantum mechanical approach to model the structure and the spectroscopic properties of the embedded chromophore. Two 10 ns molecular dynamics (MD) simulations provided input geometries for semiempirical molecular orbital (QM/MM) single-point configuration interaction (CI) calculations, which were used to calculate the wavelengths and oscillator strengths of electronic transitions in the di-8-ANEPPS dye molecule. The results were then used in a sum-over-states treatment to calculate the second-order hyperpolarizability. The square of the hyperpolarizability scales with the intensity of the second harmonic, which is used to monitor the action potentials of cardiomyocytes experimentally. Thus, we computed changes in the intensity of the second harmonic (ΔI ) as function of TMP changes. Our results agree well with experimental measurements. © 2008 American Chemical Society.

FAU Authors / FAU Editors

Clark, Timothy apl. Prof. Dr.
Kryschi, Carola Prof. Dr.
Professur für Physikalische Chemie
Lanig, Harald PD Dr.
Exzellenz-Cluster Engineering of Advanced Materials

Additional Organisation
Zentralinstitut für Scientific Computing (ZISC)

How to cite

Rusu, C.F., Lanig, H., Othersen, O., Kryschi, C., & Clark, T. (2008). Monitoring biological membrane-potential changes: A CI QM/MM study. Journal of Physical Chemistry B, 112(8), 2445-2455.

Rusu, Catalin Florin, et al. "Monitoring biological membrane-potential changes: A CI QM/MM study." Journal of Physical Chemistry B 112.8 (2008): 2445-2455.


Last updated on 2018-19-04 at 02:35