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Mohammadi H, Azami SM, Rafii-Tabar H. Density functional theory computation of the intermolecular interactions of Al 2@C 24 and Al 2@Mg 12O 12 semiconducting quantum dots conjugated with the glycine tripeptide. RSC Adv 2023; 13:9824-9837. [PMID: 36998517 PMCID: PMC10043880 DOI: 10.1039/d3ra01154b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023] Open
Abstract
The nature of intermolecular forces within semiconductor quantum dot systems can determine various physicochemical properties, as well as their functions, in nanomedical applications. The purpose of this study has been to investigate the nature of the intermolecular forces operating between Al2@C24 and Al2@Mg12O12 semiconducting quantum dots and the glycine tripeptide (GlyGlyGly), and also consider whether permanent electric dipole–dipole interactions play a significant role vis-à-vis these molecular systems. The energy computations, including the Keesom and the total electronic interactions and the energy decomposition, together with the quantum topology analyses were performed. Our results demonstrate that no significant correlation is found between the magnitude and orientation of the electrical dipole moments, and the interaction energy of the Al2@C24 and Al2@Mg12O12 with GlyGlyGly tripeptide. The Pearson correlation coefficient test revealed a very weak correlation between the quantum and the Keesom interaction energies. Apart from the quantum topology analyses, the energy decomposition consideration confirmed that the dominant share of the interaction energies was associated with the electrostatic interactions, yet both the steric and the quantum effects also made appreciable contributions. We conclude that, beside the electrical dipole–dipole interactions, other prominent intermolecular forces, such as the polarization attraction, the hydrogen bond, and the van der Waals interactions can also influence the interaction energy of the system. The findings of this study can be utilized in several areas in the field of nanobiomedicine, including the rational design of cell-penetrating and intracellular drug delivery systems using semiconducting quantum dots functionalized with a peptide. The nature of intermolecular forces within semiconducting quantum dot systems can determine various physicochemical properties, as well as their functions, in nanomedical applications.![]()
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Affiliation(s)
- Hadi Mohammadi
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Shahid Beheshti University of Medical SciencesTehranIran
| | - S. M. Azami
- Department of Chemistry, Faculty of Sciences, Yasouj UniversityYasoujIran
| | - Hashem Rafii-Tabar
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Shahid Beheshti University of Medical SciencesTehranIran
- The Physics Branch of the Academy of Sciences of IranTehranIran
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Generation of Electromagnetic Field by Microtubules. Int J Mol Sci 2021; 22:ijms22158215. [PMID: 34360980 PMCID: PMC8348406 DOI: 10.3390/ijms22158215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/23/2021] [Accepted: 07/27/2021] [Indexed: 02/02/2023] Open
Abstract
The general mechanism of controlling, information and organization in biological systems is based on the internal coherent electromagnetic field. The electromagnetic field is supposed to be generated by microtubules composed of identical tubulin heterodimers with periodic organization and containing electric dipoles. We used a classical dipole theory of generation of the electromagnetic field to analyze the space–time coherence. The structure of microtubules with the helical and axial periodicity enables the interaction of the field in time shifted by one or more periods of oscillation and generation of coherent signals. Inner cavity excitation should provide equal energy distribution in a microtubule. The supplied energy coherently excites oscillators with a high electrical quality, microtubule inner cavity, and electrons at molecular orbitals and in ‘semiconduction’ and ‘conduction’ bands. The suggested mechanism is supposed to be a general phenomenon for a large group of helical systems.
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Todorov MI, Kékesi KA, Borhegyi Z, Galambos R, Juhász G, Hudetz AG. Retino-cortical stimulus frequency-dependent gamma coupling: evidence and functional implications of oscillatory potentials. Physiol Rep 2017; 4:4/19/e12986. [PMID: 27702884 PMCID: PMC5064138 DOI: 10.14814/phy2.12986] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 09/06/2016] [Indexed: 11/24/2022] Open
Abstract
Long‐range gamma band EEG oscillations mediate information transmission between distant brain regions. Gamma band‐based coupling may not be restricted to cortex‐to‐cortex communication but may include extracortical parts of the visual system. The retinogram and visual event‐related evoked potentials exhibit time‐locked, forward propagating oscillations that are candidates of gamma oscillatory coupling between the retina and the visual cortex. In this study, we tested if this gamma coupling is present as indicated by the coherence of gamma‐range (70–200 Hz) oscillatory potentials (OPs) recorded simultaneously from the retina and the primary visual cortex in freely moving, adult rats. We found significant retino‐cortical OP coherence in a wide range of stimulus duration (0.01–1000 msec), stimulus intensity (800–5000 mcd/mm2), interstimulus interval (10–400 msec), and stimulus frequency (0.25–25 Hz). However, at low stimulus frequencies, the OPs were time‐locked, flickering light at 25 Hz entrained continuous OP coherence (steady‐state response, SSR). Our results suggest that the retina and the visual cortex exhibit oscillatory coupling at high‐gamma frequency with precise time locking and synchronization of information transfer from the retina to the visual cortex, similar to cortico‐cortical gamma coupling. The temporal fusion of retino‐cortical gamma coherence at stimulus rates of theater movies may explain the mechanism of the visual illusion of continuity. How visual perception depends on early transformations of ascending sensory information is incompletely understood. By simultaneous measurement of flash‐evoked potentials in the retina and the visual cortex in awake, freely moving rats, we demonstrate for the first time that time‐locked gamma oscillatory potentials exhibit stable retino‐cortical synchrony across a wide range of stimulus parameters and that the temporal continuity of coherence changes with stimulus frequency according to the expected change in the visual illusion of continuity.
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Affiliation(s)
- Mihail I Todorov
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Katalin A Kékesi
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, Budapest, Hungary Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
| | - Zsolt Borhegyi
- MTA-ELTE-NAP B-Opto-Neuropharmacology Group, Eötvös Loránd University, Budapest, Hungary
| | | | - Gábor Juhász
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Anthony G Hudetz
- Department of Anesthesiology, Center for Consciousness Science University of Michigan, Ann Arbor, Michigan
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Sekulic DL, Sataric BM, Zdravkovic S, Bugay AN, Sataric MV. Nonlinear dynamics of C-terminal tails in cellular microtubules. CHAOS (WOODBURY, N.Y.) 2016; 26:073119. [PMID: 27475079 DOI: 10.1063/1.4959802] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The mechanical and electrical properties, and information processing capabilities of microtubules are the permanent subject of interest for carrying out experiments in vitro and in silico, as well as for theoretical attempts to elucidate the underlying processes. In this paper, we developed a new model of the mechano-electrical waves elicited in the rows of very flexible C-terminal tails which decorate the outer surface of each microtubule. The fact that C-terminal tails play very diverse roles in many cellular functions, such as recruitment of motor proteins and microtubule-associated proteins, motivated us to consider their collective dynamics as the source of localized waves aimed for communication between microtubule and associated proteins. Our approach is based on the ferroelectric liquid crystal model and it leads to the effective asymmetric double-well potential which brings about the conditions for the appearance of kink-waves conducted by intrinsic electric fields embedded in microtubules. These kinks can serve as the signals for control and regulation of intracellular traffic along microtubules performed by processive motions of motor proteins, primarly from kinesin and dynein families. On the other hand, they can be precursors for initiation of dynamical instability of microtubules by recruiting the proper proteins responsible for the depolymerization process.
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Affiliation(s)
- Dalibor L Sekulic
- University of Novi Sad, Faculty of Technical Sciences, Novi Sad, Serbia
| | - Bogdan M Sataric
- University of Novi Sad, Faculty of Technical Sciences, Novi Sad, Serbia
| | - Slobodan Zdravkovic
- University of Belgrade, Institute of Nuclear Sciences Vinca, Belgrade, Serbia
| | - Aleksandr N Bugay
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Russia
| | - Miljko V Sataric
- University of Novi Sad, Faculty of Technical Sciences, Novi Sad, Serbia
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Zdravković S, Bugay AN, Aru GF, Maluckov A. Localized modulated waves in microtubules. CHAOS (WOODBURY, N.Y.) 2014; 24:023139. [PMID: 24985453 DOI: 10.1063/1.4885777] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In the present paper, we study nonlinear dynamics of microtubules (MTs). As an analytical method, we use semi-discrete approximation and show that localized modulated solitonic waves move along MT. This is supported by numerical analysis. Both cases with and without viscosity effects are studied.
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Affiliation(s)
- Slobodan Zdravković
- Laboratorija za Atomsku Fiziku (040), Institut za Nuklearne Nauke Vinča, Univerzitet u Beogradu, Poštanski fah 522, 11001 Beograd, Serbia
| | - Aleksandr N Bugay
- Joint Institute for Nuclear Research, Joliot-Curie 6, 141980, Dubna, Moscow Region, Russia
| | - Guzel F Aru
- Joint Institute for Nuclear Research, Joliot-Curie 6, 141980, Dubna, Moscow Region, Russia
| | - Aleksandra Maluckov
- Laboratorija za Atomsku Fiziku (040), Institut za Nuklearne Nauke Vinča, Univerzitet u Beogradu, Poštanski fah 522, 11001 Beograd, Serbia
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Goodman G, Bercovich D. Electromagnetic induction between axons and their schwann cell myelin-protein sheaths. J Integr Neurosci 2014; 12:475-89. [PMID: 24372067 DOI: 10.1142/s0219635213500295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two concepts have long dominated vertebrate nerve electrophysiology: (a) Schwann cell-formed myelin sheaths separated by minute non-myelinated nodal gaps and spiraling around axons of peripheral motor nerves reduce current leakage during propagation of trains of axon action potentials; (b) "jumping" by action potentials between successive nodes greatly increases signal conduction velocity. Long-held and more recent assumptions and issues underlying those concepts have been obscured by research emphasis on axon-sheath biochemical symbiosis and nerve regeneration. We hypothesize: mutual electromagnetic induction in the axon-glial sheath association, is fundamental in signal conduction in peripheral and central myelinated axons, explains the g-ratio and is relevant to animal navigation.
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Affiliation(s)
- G Goodman
- Galil Genetic Analysis, Kazerin 12900, Israel
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Dadras A, Riazi GH, Afrasiabi A, Naghshineh A, Ghalandari B, Mokhtari F. In vitro study on the alterations of brain tubulin structure and assembly affected by magnetite nanoparticles. J Biol Inorg Chem 2013; 18:357-69. [DOI: 10.1007/s00775-013-0980-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 01/18/2013] [Indexed: 11/28/2022]
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A critical assessment of the information processing capabilities of neuronal microtubules using coherent excitations. J Biol Phys 2010; 36:53-70. [PMID: 19669419 DOI: 10.1007/s10867-009-9158-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Accepted: 04/22/2009] [Indexed: 10/20/2022] Open
Abstract
Evidence for signaling, communication, and conductivity in microtubules (MTs) has been shown through both direct and indirect means, and theoretical models predict their potential use in both classical and quantum information processing in neurons. The notion of quantum information processing within neurons has been implicated in the phenomena of consciousness, although controversies have arisen in regards to adverse physiological temperature effects on these capabilities. To investigate the possibility of quantum processes in relation to information processing in MTs, a biophysical MT model is used based on the electrostatic interior of the tubulin protein. The interior is taken to constitute a double-well potential structure within which a mobile electron is considered capable of occupying at least two distinct quantum states. These excitonic states together with MT lattice vibrations determine the state space of individual tubulin dimers within the MT lattice. Tubulin dimers are taken as quantum well structures containing an electron that can exist in either its ground state or first excited state. Following previous models involving the mechanisms of exciton energy propagation, we estimate the strength of exciton and phonon interactions and their effect on the formation and dynamics of coherent exciton domains within MTs. Also, estimates of energy and timescales for excitons, phonons, their interactions, and thermal effects are presented. Our conclusions cast doubt on the possibility of sufficiently long-lived coherent exciton/phonon structures existing at physiological temperatures in the absence of thermal isolation mechanisms. These results are discussed in comparison with previous models based on quantum effects in non-polar hydrophobic regions, which have yet to be disproved.
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Carpenter EJ, Huzil JT, Ludueña RF, Tuszynski JA. Homology modeling of tubulin: influence predictions for microtubule's biophysical properties. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2006; 36:35-43. [PMID: 16941085 DOI: 10.1007/s00249-006-0088-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 07/17/2006] [Accepted: 07/27/2006] [Indexed: 01/28/2023]
Abstract
Using comparative modeling, we have generated structural models of 475 alpha and beta tubulins. Using these models, we observed a global, structural similarity between the tubulin isotypes. However, a number of subtle differences in the isotypes physical properties, including net electric charges, solvent accessible surface areas, and electric dipole moments were also apparent. In order to examine the roles that these properties may play in microtubule (MT) assembly and stability, we have created a model to evaluate the dipole-dipole interaction energies of varying MT lattice conformations, using human tubulin isotypes as particularly important examples. We conclude that the dipole moments of each tubulin isotype may influence their functional characteristics within the cell, resulting in differences for MT assembly kinetics and stability.
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Affiliation(s)
- Eric J Carpenter
- Department of Oncology, Division of Experimental Oncology, University of Alberta, Cross Cancer Institute, Edmonton, AB, Canada T6G 1Z2
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