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A zeta potential value determines the aggregate's size of penta-substituted [60]fullerene derivatives in aqueous suspension whereas positive charge is required for toxicity against bacterial cells.

Deryabin DG, Efremova LV, Vasilchenko AS, Saidakova EV, Sizova EA, Troshin PA, Zhilenkov AV, Khakina EA, Khakina EE - J Nanobiotechnology (2015)

Bottom Line: The prevalence of DLVO-related effects was shown in salt-added aqueous suspension that decreased zeta potential values and affected the aggregation of [60]fullerene derivatives expressed differently for individual compounds.A bioluminescence inhibition assay demonstrated that the toxic effect of [60]fullerene derivatives against E. coli cells was strictly determined by their positive zeta potential charge value being weakened against P. phosphoreum cells in an aquatic system of high salinity.The following zeta potential inversion on the bacterial cells surface was observed as an early stage of toxicity mechanism that violates the membrane-associated energetic functions.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Orenburg State University, Orenburg, Russia. dgderyabin@yandex.ru.

ABSTRACT

Background: The cause-effect relationships between physicochemical properties of amphiphilic [60]fullerene derivatives and their toxicity against bacterial cells have not yet been clarified. In this study, we report how the differences in the chemical structure of organic addends in 10 originally synthesized penta-substituted [60]fullerene derivatives modulate their zeta potential and aggregate's size in salt-free and salt-added aqueous suspensions as well as how these physicochemical characteristics affect the bioenergetics of freshwater Escherichia coli and marine Photobacterium phosphoreum bacteria. Dynamic light scattering, laser Doppler micro-electrophoresis, agarose gel electrophoresis, atomic force microscopy, and bioluminescence inhibition assay were used to characterize the fullerene aggregation behavior in aqueous solution and their interaction with the bacterial cell surface, following zeta potential changes and toxic effects.

Results: Dynamic light scattering results indicated the formation of self-assembled [60]fullerene aggregates in aqueous suspensions. The measurement of the zeta potential of the particles revealed that they have different surface charges. The relationship between these physicochemical characteristics was presented as an exponential regression that correctly described the dependence of the aggregate's size of penta-substituted [60]fullerene derivatives in salt-free aqueous suspension from zeta potential value. The prevalence of DLVO-related effects was shown in salt-added aqueous suspension that decreased zeta potential values and affected the aggregation of [60]fullerene derivatives expressed differently for individual compounds. A bioluminescence inhibition assay demonstrated that the toxic effect of [60]fullerene derivatives against E. coli cells was strictly determined by their positive zeta potential charge value being weakened against P. phosphoreum cells in an aquatic system of high salinity. Atomic force microscopy data suggested that the activity of positively charged [60]fullerene derivatives against bacterial cells required their direct interaction. The following zeta potential inversion on the bacterial cells surface was observed as an early stage of toxicity mechanism that violates the membrane-associated energetic functions.

Conclusions: The novel data about interrelations between physicochemical parameters and toxic properties of amphiphilic [60]fullerene derivatives make possible predicting their behavior in aquatic environment and their activity against bacterial cells.

No MeSH data available.


Related in: MedlinePlus

The graph illustrates distribution of particles size and zeta potential values of [60]fullerene derivatives in aqueous suspension. Data analysis with (a) and without (b) the negative and positive sign of the particles’ surface charge. White circles negatively charged compounds; black circles positively charged compounds.
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Fig2: The graph illustrates distribution of particles size and zeta potential values of [60]fullerene derivatives in aqueous suspension. Data analysis with (a) and without (b) the negative and positive sign of the particles’ surface charge. White circles negatively charged compounds; black circles positively charged compounds.

Mentions: Figure 2a demonstrates a symmetrical point’s distribution against the ordinate axis, while the left and right parts of the graph showed a tendency to decrease in particle size with the increasing surface charge. Assuming that negative or positive electric charge is equally important in colloidal systems and that only the average charge value is significant, the diagram was pre-formed in Fig. 2b where the abscissa axis contained the modules of zeta potential values. The following statistical process for estimating the relationships among (x, y) variables gave an exponential regression:\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hat{y} = \exp (a_{0} + a_{1} \times x),$$\end{document}y^=exp(a0+a1×x),where coefficient a1 = −0.2789 and constant a0 = 15.7011. This model most correctly described the relationships between physicochemical characteristics of penta-substituted [60]fullerene derivatives in water suspension (the accuracy of the mathematical model characterized by F-criterion is 25.2958; P < 0.01). The determination coefficient value for this model, R2 = 0.7193, led to strict dependence of fullerene aggregation in aqueous suspension from the zeta potential value, determining about three quarters of particle size variability.Fig. 2


A zeta potential value determines the aggregate's size of penta-substituted [60]fullerene derivatives in aqueous suspension whereas positive charge is required for toxicity against bacterial cells.

Deryabin DG, Efremova LV, Vasilchenko AS, Saidakova EV, Sizova EA, Troshin PA, Zhilenkov AV, Khakina EA, Khakina EE - J Nanobiotechnology (2015)

The graph illustrates distribution of particles size and zeta potential values of [60]fullerene derivatives in aqueous suspension. Data analysis with (a) and without (b) the negative and positive sign of the particles’ surface charge. White circles negatively charged compounds; black circles positively charged compounds.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4528854&req=5

Fig2: The graph illustrates distribution of particles size and zeta potential values of [60]fullerene derivatives in aqueous suspension. Data analysis with (a) and without (b) the negative and positive sign of the particles’ surface charge. White circles negatively charged compounds; black circles positively charged compounds.
Mentions: Figure 2a demonstrates a symmetrical point’s distribution against the ordinate axis, while the left and right parts of the graph showed a tendency to decrease in particle size with the increasing surface charge. Assuming that negative or positive electric charge is equally important in colloidal systems and that only the average charge value is significant, the diagram was pre-formed in Fig. 2b where the abscissa axis contained the modules of zeta potential values. The following statistical process for estimating the relationships among (x, y) variables gave an exponential regression:\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hat{y} = \exp (a_{0} + a_{1} \times x),$$\end{document}y^=exp(a0+a1×x),where coefficient a1 = −0.2789 and constant a0 = 15.7011. This model most correctly described the relationships between physicochemical characteristics of penta-substituted [60]fullerene derivatives in water suspension (the accuracy of the mathematical model characterized by F-criterion is 25.2958; P < 0.01). The determination coefficient value for this model, R2 = 0.7193, led to strict dependence of fullerene aggregation in aqueous suspension from the zeta potential value, determining about three quarters of particle size variability.Fig. 2

Bottom Line: The prevalence of DLVO-related effects was shown in salt-added aqueous suspension that decreased zeta potential values and affected the aggregation of [60]fullerene derivatives expressed differently for individual compounds.A bioluminescence inhibition assay demonstrated that the toxic effect of [60]fullerene derivatives against E. coli cells was strictly determined by their positive zeta potential charge value being weakened against P. phosphoreum cells in an aquatic system of high salinity.The following zeta potential inversion on the bacterial cells surface was observed as an early stage of toxicity mechanism that violates the membrane-associated energetic functions.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Orenburg State University, Orenburg, Russia. dgderyabin@yandex.ru.

ABSTRACT

Background: The cause-effect relationships between physicochemical properties of amphiphilic [60]fullerene derivatives and their toxicity against bacterial cells have not yet been clarified. In this study, we report how the differences in the chemical structure of organic addends in 10 originally synthesized penta-substituted [60]fullerene derivatives modulate their zeta potential and aggregate's size in salt-free and salt-added aqueous suspensions as well as how these physicochemical characteristics affect the bioenergetics of freshwater Escherichia coli and marine Photobacterium phosphoreum bacteria. Dynamic light scattering, laser Doppler micro-electrophoresis, agarose gel electrophoresis, atomic force microscopy, and bioluminescence inhibition assay were used to characterize the fullerene aggregation behavior in aqueous solution and their interaction with the bacterial cell surface, following zeta potential changes and toxic effects.

Results: Dynamic light scattering results indicated the formation of self-assembled [60]fullerene aggregates in aqueous suspensions. The measurement of the zeta potential of the particles revealed that they have different surface charges. The relationship between these physicochemical characteristics was presented as an exponential regression that correctly described the dependence of the aggregate's size of penta-substituted [60]fullerene derivatives in salt-free aqueous suspension from zeta potential value. The prevalence of DLVO-related effects was shown in salt-added aqueous suspension that decreased zeta potential values and affected the aggregation of [60]fullerene derivatives expressed differently for individual compounds. A bioluminescence inhibition assay demonstrated that the toxic effect of [60]fullerene derivatives against E. coli cells was strictly determined by their positive zeta potential charge value being weakened against P. phosphoreum cells in an aquatic system of high salinity. Atomic force microscopy data suggested that the activity of positively charged [60]fullerene derivatives against bacterial cells required their direct interaction. The following zeta potential inversion on the bacterial cells surface was observed as an early stage of toxicity mechanism that violates the membrane-associated energetic functions.

Conclusions: The novel data about interrelations between physicochemical parameters and toxic properties of amphiphilic [60]fullerene derivatives make possible predicting their behavior in aquatic environment and their activity against bacterial cells.

No MeSH data available.


Related in: MedlinePlus