rus
Issue #6/2024
O.A.Farus
COMPARATIVE ANALYSIS OF THE SURFACE AND ANTIBACTERIAL PROPERTIES OF COTTON MATERIALS MODIFIED WITH SILVER AND COPPER NANOPARTICLES
COMPARATIVE ANALYSIS OF THE SURFACE AND ANTIBACTERIAL PROPERTIES OF COTTON MATERIALS MODIFIED WITH SILVER AND COPPER NANOPARTICLES
INTRODUCTION
The modern level of technology development requires atypical technological solutions from science, including in the field of textile materials modification. Modification of textile materials should contribute to emergence of new properties of the modified material and, as a consequence, to the expansion of the range of its application. Currently, one of the promising directions is considered to be develop the materials with antibacterial and bactericidal properties. The relevance of this way is due to possibility of their application as protective clothing for medical use and hygienic textiles. Moreover, this material can be used to apply to wounds, which helps to increase their healing speed [1].
Analysis of literature data allows us to identify two main ways of textile modification – treatment with organic substances with antibacterial properties, for example, antibiotics, and modification with nanoparticles, in particular, titanium (IV) oxide, silver, etc. [3–8].
Current research shows that silver nanoparticles have a unique spectrum of properties, including antibacterial, bactericidal and antiviral ones [2, 7, 9].
Currently, copper nanoparticles are quite widespread. The high potential of copper nanoparticles is due to their wide distribution in nature, biological role, and relatively low cost [4–6].
RESEARCH METHODS
To achieve the set goals and objectives, an experiment was organised, which included the following stages:
obtaining nanocomposite materials based on nanoparticles of copper, silver and cotton fabric;
comparative analysis of the surface of the obtained materials;
study of the antibacterial activity of the obtained materials.
At the first stage, we obtained nanocomposite materials of the type XM/AgNPs and XM/CuNPs.
The nanocomposite materials were obtained by synthesis of metal nanoparticles on the surface of natural material. In accordance with this method, the initial samples of textile materials (cotton samples with dimensions 5 × 5) were immersed in solutions of silver nitrate and copper (II) sulfate salts with concentration of the corresponding metal ions 0.001 mol/l with adding of ammonia for 20 minutes.
At this time, the precipitant solution is prepared. Hydrazine solution (0.0001 M) was used as precipitant.
Then the obtained materials were added into hydrosine solutions:
N2H4 + 4AgNO3 + 4NaOH = N2↑ + 4Ag↓ + 4KNO3 + 4H2O (1)
2CuSO4 + N2H4 + 4NaOH = 2Cu↓ + N2↑ + 4H2O + 2Na2SO4. (2)
Thus, preparation of nanohybrid materials is based on the impregnation method with controlled deposition reaction.
The obtained nanocomposite materials of XM/AgNPs, XM/CuNPs type after repeated washing and drying differed significantly from the initial materials in appearance. Modification promoted the appearance of colouring from golden yellow (XM/AgNPs) and light brown (XM/CuNPs). The bactericidal activity coefficient was evaluated by the disc-diffusion method.
results and discussion
As part of experimental study, a comparative analysis of surface morphology of the obtained materials with the original sample was carried out.
The surface morphology of the obtained materials was studied using a polarising optical microscope. The obtained microphotographs of the materials before and after modification were processed using ImageJ software. This program is an accessible and relatively simple tool for analysing the 3D relief of the obtained materials. Analysis of the obtained materials relief allowed us to highlight several key aspects. Firstly, deposition of silver and copper particles was carried out on the material surface, which led to the distortion of its structure. Thus, Fig.1 clearly shows the regular structure of the material in the form of clear squares. After modification with silver nanoparticles XM/AgNPs (Fig.2) and copper nanoparticles XM/CuNPs (Fig.3), no clear squareness was observed in the structure of materials. Secondly, for the treated materials, an increase in the surface area of the material along the z-axis is observed, which suggests that deposition of metal nanoparticles in the case of silver and copper nanoparticles occurs on the cotton fabric surface. Distortion of the fabric structure can be attributed to the numerous thorough washing and wringing of the material after synthesis was carried out.
To compare the antibacterial obtained materials, the disc-diffusion method was used. This method allows us to evaluate the suppression degree by silver and copper nanoparticles of surface, i.e. visualised, growth of microorganisms in Endo medium. The disc-diffusion method was chosen not accidentally, because within the framework of the study metal nanoparticles were fixed on the surface of the material, which served as a basis for a comparative analysis of effectiveness of silver and copper nanoparticles after fixation with the material. From a practical point of view, it is important that the "front" of metal nanoparticles concentration moves from the disc to periphery. The peculiarity of microorganism growth on nutrient media is the presence of lag-phase – a period of time during which the culture adapts to a new medium. At the end of the lag-phase, the growth of the microorganism culture under study starts in those areas where concentration of antibiotic has not yet exceeded minimum suppressive concentration. Thus, the longer the lag phase of a given microorganism, the larger will be the diameter of the growth inhibition zone around the disc with metal nanoparticles. The zones of growth inhibition of cultures are measured with a ruler with an accuracy of 1 mm [10]. According to this method, Endo nutrient medium was placed in three 9.3 cm diameter Petri dishes and samples (2.0 × 2.0 cm) obtained from nanomaterial with nanoparticles size were placed in two of them and the third one was left as control. Intestinal group bacteria isolated from drinking water (Escherichia coli) were seeded into all three cups by surface method.
In the first cup a sample of nanomaterial with silver nanoparticles was placed in the centre, in the second cup a sample with copper nanoparticles, the third cup we left for control. After placing the nanomaterial, the petri dishes were thermostated at optimum temperature (25 °С) for 24 hours. To calculate the total bactericidal effect, the bactericidal activity coefficient is used, which is calculated by the formula:
,
where D is the diameter of the lysis zone; d is the size of the material. According to literature data, the disc-diffusion method requires laying several series of experiments in parallel [9]. In this study, three parallel series were laid down. The obtained results are reflected in Table 1.
Presence of a lysis zone in case of modified materials, compared to the control, confirms presence of their antibacterial properties both in case of modification with silver nanoparticles and copper nanoparticles. The analysis of experimental data shows that in all three series the coefficient value of bactericidal activity for the material modified with silver nanoparticles (CM/AgNPs) is higher than the similar coefficient for the material modified with copper nanoparticles.
The size of the average value of the lysis zone for XM/AgNPs is almost twice as high as the similar value for XM/SuNPs. Moreover, the calculated value of the relative error of the sample average in both cases does not exceed 10%, which allows us to consider the results of the experiment satisfactory, therefore, the sample average (including its error) for the modified materials corresponds to the general average.
CONCLUSIONS
Thus, the results of the conducted research allow us to draw the following general conclusions:
nanostructuring of the surface of natural fabrics makes it possible to significantly expand the area of their application;
impregnation method with controlled deposition reaction can be used for surface modification of cotton materials with silver and copper nanoparticles. Hydrazine was used as a reducing agent. Although this reagent is hazardous, its use is safe because the residues of this reagent are washed off and do not remain on the surface of the material;
to analyse the surface relief of the obtained materials it is possible to use the publicly available ImageJ software. Analysis of the modified materials surface allows us to conclude about increasing the height of the material surface, which confirms the fact of fixation of metal nanoparticles on the surface of cotton material;
using the disc-diffusion method it was proved that introduction of silver and copper nanoparticles on the surface of the material leads to appearance of bactericidal activity in these materials;
the value of the relative error of the sample mean, less than 10% for the coefficient of bactericidal activity allows us to speak about the representativeness of the data.
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.
The modern level of technology development requires atypical technological solutions from science, including in the field of textile materials modification. Modification of textile materials should contribute to emergence of new properties of the modified material and, as a consequence, to the expansion of the range of its application. Currently, one of the promising directions is considered to be develop the materials with antibacterial and bactericidal properties. The relevance of this way is due to possibility of their application as protective clothing for medical use and hygienic textiles. Moreover, this material can be used to apply to wounds, which helps to increase their healing speed [1].
Analysis of literature data allows us to identify two main ways of textile modification – treatment with organic substances with antibacterial properties, for example, antibiotics, and modification with nanoparticles, in particular, titanium (IV) oxide, silver, etc. [3–8].
Current research shows that silver nanoparticles have a unique spectrum of properties, including antibacterial, bactericidal and antiviral ones [2, 7, 9].
Currently, copper nanoparticles are quite widespread. The high potential of copper nanoparticles is due to their wide distribution in nature, biological role, and relatively low cost [4–6].
RESEARCH METHODS
To achieve the set goals and objectives, an experiment was organised, which included the following stages:
obtaining nanocomposite materials based on nanoparticles of copper, silver and cotton fabric;
comparative analysis of the surface of the obtained materials;
study of the antibacterial activity of the obtained materials.
At the first stage, we obtained nanocomposite materials of the type XM/AgNPs and XM/CuNPs.
The nanocomposite materials were obtained by synthesis of metal nanoparticles on the surface of natural material. In accordance with this method, the initial samples of textile materials (cotton samples with dimensions 5 × 5) were immersed in solutions of silver nitrate and copper (II) sulfate salts with concentration of the corresponding metal ions 0.001 mol/l with adding of ammonia for 20 minutes.
At this time, the precipitant solution is prepared. Hydrazine solution (0.0001 M) was used as precipitant.
Then the obtained materials were added into hydrosine solutions:
N2H4 + 4AgNO3 + 4NaOH = N2↑ + 4Ag↓ + 4KNO3 + 4H2O (1)
2CuSO4 + N2H4 + 4NaOH = 2Cu↓ + N2↑ + 4H2O + 2Na2SO4. (2)
Thus, preparation of nanohybrid materials is based on the impregnation method with controlled deposition reaction.
The obtained nanocomposite materials of XM/AgNPs, XM/CuNPs type after repeated washing and drying differed significantly from the initial materials in appearance. Modification promoted the appearance of colouring from golden yellow (XM/AgNPs) and light brown (XM/CuNPs). The bactericidal activity coefficient was evaluated by the disc-diffusion method.
results and discussion
As part of experimental study, a comparative analysis of surface morphology of the obtained materials with the original sample was carried out.
The surface morphology of the obtained materials was studied using a polarising optical microscope. The obtained microphotographs of the materials before and after modification were processed using ImageJ software. This program is an accessible and relatively simple tool for analysing the 3D relief of the obtained materials. Analysis of the obtained materials relief allowed us to highlight several key aspects. Firstly, deposition of silver and copper particles was carried out on the material surface, which led to the distortion of its structure. Thus, Fig.1 clearly shows the regular structure of the material in the form of clear squares. After modification with silver nanoparticles XM/AgNPs (Fig.2) and copper nanoparticles XM/CuNPs (Fig.3), no clear squareness was observed in the structure of materials. Secondly, for the treated materials, an increase in the surface area of the material along the z-axis is observed, which suggests that deposition of metal nanoparticles in the case of silver and copper nanoparticles occurs on the cotton fabric surface. Distortion of the fabric structure can be attributed to the numerous thorough washing and wringing of the material after synthesis was carried out.
To compare the antibacterial obtained materials, the disc-diffusion method was used. This method allows us to evaluate the suppression degree by silver and copper nanoparticles of surface, i.e. visualised, growth of microorganisms in Endo medium. The disc-diffusion method was chosen not accidentally, because within the framework of the study metal nanoparticles were fixed on the surface of the material, which served as a basis for a comparative analysis of effectiveness of silver and copper nanoparticles after fixation with the material. From a practical point of view, it is important that the "front" of metal nanoparticles concentration moves from the disc to periphery. The peculiarity of microorganism growth on nutrient media is the presence of lag-phase – a period of time during which the culture adapts to a new medium. At the end of the lag-phase, the growth of the microorganism culture under study starts in those areas where concentration of antibiotic has not yet exceeded minimum suppressive concentration. Thus, the longer the lag phase of a given microorganism, the larger will be the diameter of the growth inhibition zone around the disc with metal nanoparticles. The zones of growth inhibition of cultures are measured with a ruler with an accuracy of 1 mm [10]. According to this method, Endo nutrient medium was placed in three 9.3 cm diameter Petri dishes and samples (2.0 × 2.0 cm) obtained from nanomaterial with nanoparticles size were placed in two of them and the third one was left as control. Intestinal group bacteria isolated from drinking water (Escherichia coli) were seeded into all three cups by surface method.
In the first cup a sample of nanomaterial with silver nanoparticles was placed in the centre, in the second cup a sample with copper nanoparticles, the third cup we left for control. After placing the nanomaterial, the petri dishes were thermostated at optimum temperature (25 °С) for 24 hours. To calculate the total bactericidal effect, the bactericidal activity coefficient is used, which is calculated by the formula:
,
where D is the diameter of the lysis zone; d is the size of the material. According to literature data, the disc-diffusion method requires laying several series of experiments in parallel [9]. In this study, three parallel series were laid down. The obtained results are reflected in Table 1.
Presence of a lysis zone in case of modified materials, compared to the control, confirms presence of their antibacterial properties both in case of modification with silver nanoparticles and copper nanoparticles. The analysis of experimental data shows that in all three series the coefficient value of bactericidal activity for the material modified with silver nanoparticles (CM/AgNPs) is higher than the similar coefficient for the material modified with copper nanoparticles.
The size of the average value of the lysis zone for XM/AgNPs is almost twice as high as the similar value for XM/SuNPs. Moreover, the calculated value of the relative error of the sample average in both cases does not exceed 10%, which allows us to consider the results of the experiment satisfactory, therefore, the sample average (including its error) for the modified materials corresponds to the general average.
CONCLUSIONS
Thus, the results of the conducted research allow us to draw the following general conclusions:
nanostructuring of the surface of natural fabrics makes it possible to significantly expand the area of their application;
impregnation method with controlled deposition reaction can be used for surface modification of cotton materials with silver and copper nanoparticles. Hydrazine was used as a reducing agent. Although this reagent is hazardous, its use is safe because the residues of this reagent are washed off and do not remain on the surface of the material;
to analyse the surface relief of the obtained materials it is possible to use the publicly available ImageJ software. Analysis of the modified materials surface allows us to conclude about increasing the height of the material surface, which confirms the fact of fixation of metal nanoparticles on the surface of cotton material;
using the disc-diffusion method it was proved that introduction of silver and copper nanoparticles on the surface of the material leads to appearance of bactericidal activity in these materials;
the value of the relative error of the sample mean, less than 10% for the coefficient of bactericidal activity allows us to speak about the representativeness of the data.
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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