rus
Issue #3-4/2025
A.A.Blinova, M.A.Pirogov, Z.A.Rekhman, A.V.Blinov E.D.Nazaretova, A.B.Golik
STUDY OF AGGREGATIVE STABILITY OF SELENIUM NANOPARTICLES STABILIZED WITH COCAMIDOPROPYLAMINE OXIDE
STUDY OF AGGREGATIVE STABILITY OF SELENIUM NANOPARTICLES STABILIZED WITH COCAMIDOPROPYLAMINE OXIDE
DOI: https://doi.org/10.22184/1993-8578.2025.18.3-4.174.182
In this work, samples of selenium nanoparticles stabilized with cocamidopropylamine oxide were obtained by chemical reduction in an aqueous medium. Quantum chemical modeling of the process of stabilization of selenium nanoparticles by cocamidopropylamine oxide molecules was carried out, as a result of which it was found that this interaction is energetically favorable (∆E ≥ 2399.568 kcal/mol) and chemically stable (0.035 ≤ n ≤ 0.067 eV), and the interaction of the selenium atom with cocamidopropylamine oxide through a secondary amino group (∆E = 2400,099, n = 0.067 eV). As a result of optimization of the synthesis method, optimal concentrations of selenic acid, ascorbic acid and cocamidopropylamine oxide were determined – 0.004, 2.118 and 0.180 mol/dm3. The stability of selenium nanoparticles was also studied depending on the active acidity of the medium and the ionic strength of the solution. It has been established that selenium particles have high stability in the pH range of the medium from 1.81 to 4.56 (from 12 ± 2 nm to 24 ± 5 nm). Based on the analysis of the dependences of the average hydrodynamic radius on the ionic strength, it was found that Na+ and Cl- ions do not significantly affect the stability of the particles (R varies from 12 ± 2 to 15 ± 2 nm), and selenium nanoparticles are stable when SO42– ions with concentrations up to 0.5 mol/dm3 are added to the sol.
In this work, samples of selenium nanoparticles stabilized with cocamidopropylamine oxide were obtained by chemical reduction in an aqueous medium. Quantum chemical modeling of the process of stabilization of selenium nanoparticles by cocamidopropylamine oxide molecules was carried out, as a result of which it was found that this interaction is energetically favorable (∆E ≥ 2399.568 kcal/mol) and chemically stable (0.035 ≤ n ≤ 0.067 eV), and the interaction of the selenium atom with cocamidopropylamine oxide through a secondary amino group (∆E = 2400,099, n = 0.067 eV). As a result of optimization of the synthesis method, optimal concentrations of selenic acid, ascorbic acid and cocamidopropylamine oxide were determined – 0.004, 2.118 and 0.180 mol/dm3. The stability of selenium nanoparticles was also studied depending on the active acidity of the medium and the ionic strength of the solution. It has been established that selenium particles have high stability in the pH range of the medium from 1.81 to 4.56 (from 12 ± 2 nm to 24 ± 5 nm). Based on the analysis of the dependences of the average hydrodynamic radius on the ionic strength, it was found that Na+ and Cl- ions do not significantly affect the stability of the particles (R varies from 12 ± 2 to 15 ± 2 nm), and selenium nanoparticles are stable when SO42– ions with concentrations up to 0.5 mol/dm3 are added to the sol.
Теги: cocamidopropylamine oxide ionic strength optimization of synthesis technique quantum chemical modeling selenium nanoparticles ионная сила квантово-химическое моделирование кокамидопропиламиноксид наночастицы селена оптимизация методики синтеза
INTRODUCTION
Selenium is an important trace element for many living organisms, as it is involved in a number of physiological and metabolic processes, and is also a constituent of 25 selenoproteins in mammals [1]. For humans, the daily intake of selenium is 0.07 mg for men and 0.06 mg for women [2]. Selenium deficiency can lead to serious diseases such as Kashin-Beck disease, Keshan disease and weakening of the immune system to viral infectious diseases such as influenza, HIV, cystic fibrosis, etc. [3]. Development of drugs and biologically active selenium-containing substances for prevention and treatment of selenium deficiency is topical [4].
In plants, selenium does not play an important metabolic role, but low concentrations of Se can have a positive effect on plant growth and development as an antioxidant, antimicrobial and stress-modulating agent [5, 6].
The use of nanosized form of selenium instead of inorganic form has become one of the ways to enhance its beneficial properties. As a result of studies, it was found that selenium nanoparticles are non-toxic, exhibit pronounced antioxidant activity, have greater bioactivity and bioavailability [7]. Due to its unique properties, nanosized selenium has wide prospects of application in agricultural and food industries [8]. The development of antimicrobial agents, growth stimulators and fertilisers based on selenium nanoparticles is underway [9]. The application of selenium nanoparticles in the field of food packaging materials with antioxidant and antibacterial properties is also being considered [10]. In the pharmaceutical industry, innovative drugs based on selenium nanoparticles are being developed and research is being carried out in the field of targeted drug delivery. Such drugs can be used to treat tumour diseases [11]. Biologically active supplements are being developed to prevent selenium deficiency [12].
Most often selenium nanoparticles are prepared by direct chemical synthesis in aqueous medium. To stabilise selenium nanoparticles, various classes of surfactants (surfactants) and various polymeric compounds are used [13]. For example, cocamidopropylaminoxide (Twalam P18) is a non-ionogenic surfactant used in medicine, cosmetology and agriculture due to its anti-inflammatory and bactericidal properties [14].
The aim of this work is to study selenium
nanoparticles properties stabilised with cocamido-propylaminoxide.
RESEARCH METHODS
At the first stage, quantum-chemical modelling of the process of stabilisation of selenium nanoparticles by cocamidopropylaminoxide molecules was carried out. The molecules were constructed in the molecular editor IQmol. The values of the total energy of the molecular complex (E), the energy of the highest populated molecular orbital (EHOMO), and the energy of the lowest free molecular orbital (ELUMO) were calculated. The calculation was performed using Qchem software on the equipment of the data processing centre (Schneider Electric) of the Federal State Educational Institution of Higher Education of the North Caucasus Federal University with the following parameters: method: B3LYP, basis: 6-31G*, convergence – 5, force field – Ghemical. Within the framework of quantum-chemical modelling the elementary interaction act of cocamidopropylaminoxide molecule with selenium atom through different functional groups was considered.
Samples of selenium nanoparticles stabilised with cocamidopropylaminoxide were prepared according to the following procedure: in the first step, selenic acid solution was mixed with cocamidopropylaminoxide and stirred for 5 minutes at 500 rpm; in the next step, ascorbic acid solution was added to the resulting mixture and stirred for 5 minutes at 500 rpm.
In order to determine the optimal concentrations of components, the synthesis technique was optimised using the experimental matrix presented in Table 1. The average hydrodynamic radius of particles measured using the method of dynamic light scattering on a multi-angle particle size analyser Photocor Complex (Antec-97 LLC, Russia) was considered as an output parameter. The obtained data were processed using Statistica software and Statistica Neural Networks application package.
In the next step, stability of selenium nanoparticles fixed by cocamidopropylaminoxide was studied from the pH of the medium. For this purpose buffer solutions were prepared with pH values: 1.81, 2.21, 3.29, 4.56, 5.75, 6.8, 7.96, 9.15, 10.38, 11.58, 11.98. Active acidity of the medium was measured using a pH-meter (ionometer) Expert-001 (Econix-Expert, Russia) with a combined pH electrode ESC-10605/7 with a temperature sensor. The obtained solutions were mixed with selenium nanoparticles stabilised with cocamidopropylaminoxide in a 1:1 ratio and then studied by dynamic light scattering.
Further, selenium nanoparticles stability fixed by cocamidopropylaminoxide from ionic strength was studied. For this purpose, solutions of NaCl, Na2SO4, K3PO4, BaCl2, and FeCl3 with concentrations of 0.1, 0.25, 0.5, 0.75, and 1 mol/dm3 were prepared. The obtained solutions were mixed with selenium nanoparticles stabilised with cocamidopropylaminoxide in a 1:1 ratio and then studied by dynamic light scattering.
RESULTS
At the first stage, quantum-chemical modelling of the stabilisation process of selenium nanoparticles by cocamidopropylaminoxide molecules was carried out. As a result, the values of the calculated parameters presented in Table 1 were obtained. The model of molecular complex, model of electron density distribution, electron density gradient, and models of the highest populated and lowest free molecular orbitals for the most energetically favourable variant of interaction of selenium atom with cocamidopropylaminoxide are presented in Fig.2.
Further optimisation of the methodology for the synthesis of selenium nanoparticles was carried out. The ternary surface of the dependence of the average hydrodynamic radius of particles on the concentration of selenic acid, ascorbic acid and cocamidopropylaminoxide is presented in Fig.2.
In the next step, the aggregative stability of selenium nanoparticles stabilised with
cocamidopropylaminoxide was studied from the medium active acidity. The dependence of the average hydrodynamic radius of particles on the pH-medium is presented in Fig.3.
After this, stability of selenium nanoparticles fixed by cocamidopropylaminoxide from ionic strength was studied. The dependence of the average hydrodynamic radius of particles on ion concentration is presented in Fig.4.
DISCUSSION
Based on the analysis of quantum-chemical modelling results, interaction of selenium atom with cocamidopropylaminoxide molecule was found to be energetically favourable (∆E ≥ 2399.568 kcal/mol) and chemically stable (0.035 ≤ η ≤ 0.067 eV). Interaction of the selenium atom with cocamidopropylaminoxide via the secondary amino group is the most probable, as it is the most energetically favourable (∆E = 2400.099 kcal/mol) and chemically stable (η = 0.067 eV).
When analysing the obtained ternary dependence, it was revealed that with increasing ascorbic acid concentration, a decrease in the mean hydrodynamic radius is observed, while increasing selenic acid content leads to the particle size growth. It is worth noting that changing concentration of stabiliser has no significant effect on the particle size. Based on the data obtained, the particles were found to have the largest hydrodynamic radius (34 ± 6 nm) at selenic acid, ascorbic acid and cocamidopropylaminoxide concentrations of 0.236, 1.076 and 0.006 mol/dm3, respectively, and the smallest (12 ± 2 nm) at selenic acid, ascorbic acid and cocamidopropylaminoxide concentrations of 0.004, 2.118 and 0.180 mol/dm3, respectively.
Analysis of the effect of pH of the medium on aggregative stability of selenium particles fixed with cocamidopropylaminoxide showed that selenium particles were highly stable in the pH range from 1.81 to 4.56, as the particle size increased from 12 ± 2 to 24 ± 5 nm. At the same time, with further increase in pH of the medium, the mean hydrodynamic radius increases and ranges from 93 ± 6 to 110 ± 6 nm, but this change does not lead to precipitation and colour change of the solution.
The analysis of the dependence of the mean hydrodynamic radius on the anion concentration showed that Cl- ions have no significant effect on of selenium particles stability, as the mean hydrodynamic radius increases from 12 ± 2 to 15 ± 2 nm. On addition of SO42– ions with concentration of 0.75 mol/dm3, an increase in the hydrodynamic radius to 26 ± 2 nm was observed, and on increasing concentration of sulphate ions to 1 mol/dm3, the size increased to 37 ± 2 nm. Сoncentration of PO43– has a significant effect on the mean hydrodynamic radius, as evidenced by the fact that when the PO43– ion concentration is increased to 0.1 mol/dm3, the mean hydrodynamic radius increases to 73 ± 6 nm, and at subsequent increases it ranges from 125 ± 13 to 137 ± 13 nm.
The analysis of the dependence of the average hydrodynamic radius on the concentration of cations showed that Na+ ions, as well as Cl- ions, have no effect on the stability of selenium particles. At the same time, there is a change in the size of selenium particles with increasing concentration of Ba2 + and Fe3 + ions. Thus, when their concentration increases up to 1 mol/dm3, the radius of selenium nanoparticles increases to 550 ± 25 and 800 ± 25 nm, respectively. The obtained results are consistent with the Schulze-Gardi rule, since the coagulation ability of electrolytes increases in direct proportion to their charge.
CONCLUSIONS
Thus, quantum-chemical modelling of the stabilisation process of selenium nanoparticles by cocamidopropylaminoxide molecules has been carried out within the framework of this work, and as a result it has been established that interaction of cocamidopropylaminoxide molecule with selenium is energetically advantageous and chemically stable, and the most probable is interaction of cocamidopropylaminoxide molecule with selenium through the secondary amino group. Optimisation of selenium nanoparticles synthesis technique depending on concentration of initial reagents was also carried out, as a result of which optimal concentrations of selenic acid, ascorbic acid and cocamidopropylaminoxide were determined. After that, stability of selenium particles depending on pH-environment and ionic strength of the solution was studied. On analysing the obtained data, it was found that selenium nanoparticles were stable in the range of pH from 1.81 to 4.56, and in the range of Na+ and Cl- ion concentration from 0 to 1 mol/dm3 and SO42– ion concentration from 0 to 0.5 mol/dm3.
ACKNOWLEDGEMENTS
The study was performed by a grant provided by the Russian Science Foundation, No. 23-16-00120, https://rscf.ru/project/23-16-00120/.
PEER REVIEW INFO
Editorial board thanks the anonymous reviewer(s) for their contribution to the peer review of this work. It is also grateful for their consent to publish papers on the journal’s website and SEL eLibrary eLIBRARY.RU.
Declaration of Competing Interest. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Selenium is an important trace element for many living organisms, as it is involved in a number of physiological and metabolic processes, and is also a constituent of 25 selenoproteins in mammals [1]. For humans, the daily intake of selenium is 0.07 mg for men and 0.06 mg for women [2]. Selenium deficiency can lead to serious diseases such as Kashin-Beck disease, Keshan disease and weakening of the immune system to viral infectious diseases such as influenza, HIV, cystic fibrosis, etc. [3]. Development of drugs and biologically active selenium-containing substances for prevention and treatment of selenium deficiency is topical [4].
In plants, selenium does not play an important metabolic role, but low concentrations of Se can have a positive effect on plant growth and development as an antioxidant, antimicrobial and stress-modulating agent [5, 6].
The use of nanosized form of selenium instead of inorganic form has become one of the ways to enhance its beneficial properties. As a result of studies, it was found that selenium nanoparticles are non-toxic, exhibit pronounced antioxidant activity, have greater bioactivity and bioavailability [7]. Due to its unique properties, nanosized selenium has wide prospects of application in agricultural and food industries [8]. The development of antimicrobial agents, growth stimulators and fertilisers based on selenium nanoparticles is underway [9]. The application of selenium nanoparticles in the field of food packaging materials with antioxidant and antibacterial properties is also being considered [10]. In the pharmaceutical industry, innovative drugs based on selenium nanoparticles are being developed and research is being carried out in the field of targeted drug delivery. Such drugs can be used to treat tumour diseases [11]. Biologically active supplements are being developed to prevent selenium deficiency [12].
Most often selenium nanoparticles are prepared by direct chemical synthesis in aqueous medium. To stabilise selenium nanoparticles, various classes of surfactants (surfactants) and various polymeric compounds are used [13]. For example, cocamidopropylaminoxide (Twalam P18) is a non-ionogenic surfactant used in medicine, cosmetology and agriculture due to its anti-inflammatory and bactericidal properties [14].
The aim of this work is to study selenium
nanoparticles properties stabilised with cocamido-propylaminoxide.
RESEARCH METHODS
At the first stage, quantum-chemical modelling of the process of stabilisation of selenium nanoparticles by cocamidopropylaminoxide molecules was carried out. The molecules were constructed in the molecular editor IQmol. The values of the total energy of the molecular complex (E), the energy of the highest populated molecular orbital (EHOMO), and the energy of the lowest free molecular orbital (ELUMO) were calculated. The calculation was performed using Qchem software on the equipment of the data processing centre (Schneider Electric) of the Federal State Educational Institution of Higher Education of the North Caucasus Federal University with the following parameters: method: B3LYP, basis: 6-31G*, convergence – 5, force field – Ghemical. Within the framework of quantum-chemical modelling the elementary interaction act of cocamidopropylaminoxide molecule with selenium atom through different functional groups was considered.
Samples of selenium nanoparticles stabilised with cocamidopropylaminoxide were prepared according to the following procedure: in the first step, selenic acid solution was mixed with cocamidopropylaminoxide and stirred for 5 minutes at 500 rpm; in the next step, ascorbic acid solution was added to the resulting mixture and stirred for 5 minutes at 500 rpm.
In order to determine the optimal concentrations of components, the synthesis technique was optimised using the experimental matrix presented in Table 1. The average hydrodynamic radius of particles measured using the method of dynamic light scattering on a multi-angle particle size analyser Photocor Complex (Antec-97 LLC, Russia) was considered as an output parameter. The obtained data were processed using Statistica software and Statistica Neural Networks application package.
In the next step, stability of selenium nanoparticles fixed by cocamidopropylaminoxide was studied from the pH of the medium. For this purpose buffer solutions were prepared with pH values: 1.81, 2.21, 3.29, 4.56, 5.75, 6.8, 7.96, 9.15, 10.38, 11.58, 11.98. Active acidity of the medium was measured using a pH-meter (ionometer) Expert-001 (Econix-Expert, Russia) with a combined pH electrode ESC-10605/7 with a temperature sensor. The obtained solutions were mixed with selenium nanoparticles stabilised with cocamidopropylaminoxide in a 1:1 ratio and then studied by dynamic light scattering.
Further, selenium nanoparticles stability fixed by cocamidopropylaminoxide from ionic strength was studied. For this purpose, solutions of NaCl, Na2SO4, K3PO4, BaCl2, and FeCl3 with concentrations of 0.1, 0.25, 0.5, 0.75, and 1 mol/dm3 were prepared. The obtained solutions were mixed with selenium nanoparticles stabilised with cocamidopropylaminoxide in a 1:1 ratio and then studied by dynamic light scattering.
RESULTS
At the first stage, quantum-chemical modelling of the stabilisation process of selenium nanoparticles by cocamidopropylaminoxide molecules was carried out. As a result, the values of the calculated parameters presented in Table 1 were obtained. The model of molecular complex, model of electron density distribution, electron density gradient, and models of the highest populated and lowest free molecular orbitals for the most energetically favourable variant of interaction of selenium atom with cocamidopropylaminoxide are presented in Fig.2.
Further optimisation of the methodology for the synthesis of selenium nanoparticles was carried out. The ternary surface of the dependence of the average hydrodynamic radius of particles on the concentration of selenic acid, ascorbic acid and cocamidopropylaminoxide is presented in Fig.2.
In the next step, the aggregative stability of selenium nanoparticles stabilised with
cocamidopropylaminoxide was studied from the medium active acidity. The dependence of the average hydrodynamic radius of particles on the pH-medium is presented in Fig.3.
After this, stability of selenium nanoparticles fixed by cocamidopropylaminoxide from ionic strength was studied. The dependence of the average hydrodynamic radius of particles on ion concentration is presented in Fig.4.
DISCUSSION
Based on the analysis of quantum-chemical modelling results, interaction of selenium atom with cocamidopropylaminoxide molecule was found to be energetically favourable (∆E ≥ 2399.568 kcal/mol) and chemically stable (0.035 ≤ η ≤ 0.067 eV). Interaction of the selenium atom with cocamidopropylaminoxide via the secondary amino group is the most probable, as it is the most energetically favourable (∆E = 2400.099 kcal/mol) and chemically stable (η = 0.067 eV).
When analysing the obtained ternary dependence, it was revealed that with increasing ascorbic acid concentration, a decrease in the mean hydrodynamic radius is observed, while increasing selenic acid content leads to the particle size growth. It is worth noting that changing concentration of stabiliser has no significant effect on the particle size. Based on the data obtained, the particles were found to have the largest hydrodynamic radius (34 ± 6 nm) at selenic acid, ascorbic acid and cocamidopropylaminoxide concentrations of 0.236, 1.076 and 0.006 mol/dm3, respectively, and the smallest (12 ± 2 nm) at selenic acid, ascorbic acid and cocamidopropylaminoxide concentrations of 0.004, 2.118 and 0.180 mol/dm3, respectively.
Analysis of the effect of pH of the medium on aggregative stability of selenium particles fixed with cocamidopropylaminoxide showed that selenium particles were highly stable in the pH range from 1.81 to 4.56, as the particle size increased from 12 ± 2 to 24 ± 5 nm. At the same time, with further increase in pH of the medium, the mean hydrodynamic radius increases and ranges from 93 ± 6 to 110 ± 6 nm, but this change does not lead to precipitation and colour change of the solution.
The analysis of the dependence of the mean hydrodynamic radius on the anion concentration showed that Cl- ions have no significant effect on of selenium particles stability, as the mean hydrodynamic radius increases from 12 ± 2 to 15 ± 2 nm. On addition of SO42– ions with concentration of 0.75 mol/dm3, an increase in the hydrodynamic radius to 26 ± 2 nm was observed, and on increasing concentration of sulphate ions to 1 mol/dm3, the size increased to 37 ± 2 nm. Сoncentration of PO43– has a significant effect on the mean hydrodynamic radius, as evidenced by the fact that when the PO43– ion concentration is increased to 0.1 mol/dm3, the mean hydrodynamic radius increases to 73 ± 6 nm, and at subsequent increases it ranges from 125 ± 13 to 137 ± 13 nm.
The analysis of the dependence of the average hydrodynamic radius on the concentration of cations showed that Na+ ions, as well as Cl- ions, have no effect on the stability of selenium particles. At the same time, there is a change in the size of selenium particles with increasing concentration of Ba2 + and Fe3 + ions. Thus, when their concentration increases up to 1 mol/dm3, the radius of selenium nanoparticles increases to 550 ± 25 and 800 ± 25 nm, respectively. The obtained results are consistent with the Schulze-Gardi rule, since the coagulation ability of electrolytes increases in direct proportion to their charge.
CONCLUSIONS
Thus, quantum-chemical modelling of the stabilisation process of selenium nanoparticles by cocamidopropylaminoxide molecules has been carried out within the framework of this work, and as a result it has been established that interaction of cocamidopropylaminoxide molecule with selenium is energetically advantageous and chemically stable, and the most probable is interaction of cocamidopropylaminoxide molecule with selenium through the secondary amino group. Optimisation of selenium nanoparticles synthesis technique depending on concentration of initial reagents was also carried out, as a result of which optimal concentrations of selenic acid, ascorbic acid and cocamidopropylaminoxide were determined. After that, stability of selenium particles depending on pH-environment and ionic strength of the solution was studied. On analysing the obtained data, it was found that selenium nanoparticles were stable in the range of pH from 1.81 to 4.56, and in the range of Na+ and Cl- ion concentration from 0 to 1 mol/dm3 and SO42– ion concentration from 0 to 0.5 mol/dm3.
ACKNOWLEDGEMENTS
The study was performed by a grant provided by the Russian Science Foundation, No. 23-16-00120, https://rscf.ru/project/23-16-00120/.
PEER REVIEW INFO
Editorial board thanks the anonymous reviewer(s) for their contribution to the peer review of this work. It is also grateful for their consent to publish papers on the journal’s website and SEL eLibrary eLIBRARY.RU.
Declaration of Competing Interest. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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