Antibacterial Effect of Colloidal Suspensions Varying in Silver Nanoparticles and Ions Concentrations
A lot of effort has been dedicated recently to provide a better insight into the mechanism of the antibacterial activity of silver nanoparticles (AgNPs) colloidal suspensions and their released silver ionic counterparts. However, there is no consistency regarding whether the antibacterial effect dis...
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MDPI AG
2021-12-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/12/1/31 |
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| author | Varvara Platania Alexandra Kaldeli-Kerou Theodora Karamanidou Maria Kouki Alexander Tsouknidas Maria Chatzinikolaidou |
| author_facet | Varvara Platania Alexandra Kaldeli-Kerou Theodora Karamanidou Maria Kouki Alexander Tsouknidas Maria Chatzinikolaidou |
| author_sort | Varvara Platania |
| collection | DOAJ |
| description | A lot of effort has been dedicated recently to provide a better insight into the mechanism of the antibacterial activity of silver nanoparticles (AgNPs) colloidal suspensions and their released silver ionic counterparts. However, there is no consistency regarding whether the antibacterial effect displayed at cellular level originates from the AgNPs or their ionic constitutes. To address this issue, three colloidal suspensions exhibiting different ratios of AgNPs/silver ions were synthesized by a wet chemistry method in conjunction with tangential flow filtration, and were characterized and evaluated for their antimicrobial properties against two gram-negative, <i>Escherichia coli</i> (<i>E. coli</i>) and <i>Pseudomonas aeruginosa</i> (<i>P. aeruginosa</i>), and two gram-positive, <i>Staphylococcus aureus</i> (<i>S. aureus</i>) and <i>Staphylococcus epidermidis</i> (<i>S. epidermidis</i>), bacterial strains. The produced samples contained 25% AgNPs and 75% Ag ions (AgNP_25), 50% AgNPs and 50% Ag ions (AgNP_50), and 100% AgNPs (AgNP_100). The sample AgNP_100 demonstrated the lowest minimum inhibitory concentration values ranging from 4.6 to 15.6 ppm for all four bacterial strains, while all three samples indicated minimum bactericidal concentration (MBC) values ranging from 16.6 ppm to 62.5 ppm against all strains. An increase in silver ions content results in higher bactericidal activity. All three samples were found to lead to a significant morphological damage by disruption of the bacterial cell membranes as analyzed by means of scanning electron microscopy (SEM). The growth kinetics demonstrated that all three samples were able to reduce the bacterial population at a concentration of 3.1 ppm. SEM and growth kinetic data underline that <i>S. epidermidis</i> is the most sensitive among all strains against the investigated samples. Our results showed that all three AgNPs colloidal suspensions exhibited strong antibacterial properties and, thus, they can be applied in medical devices and antimicrobial control systems. |
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| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-10T03:29:26Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
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| series | Nanomaterials |
| spelling | doaj.art-eb3dcaa0c00f4e8db8dbf1d4836b3b342023-11-23T12:00:30ZengMDPI AGNanomaterials2079-49912021-12-011213110.3390/nano12010031Antibacterial Effect of Colloidal Suspensions Varying in Silver Nanoparticles and Ions ConcentrationsVarvara Platania0Alexandra Kaldeli-Kerou1Theodora Karamanidou2Maria Kouki3Alexander Tsouknidas4Maria Chatzinikolaidou5Department of Materials Science and Technology, University of Crete, 70013 Heraklion, GreecePLiN Nanotechnology S.A., Spectra Business Center 12th km Thessaloniki-Chalkidiki, Thermi, 57001 Thessaloniki, GreecePLiN Nanotechnology S.A., Spectra Business Center 12th km Thessaloniki-Chalkidiki, Thermi, 57001 Thessaloniki, GreecePLiN Nanotechnology S.A., Spectra Business Center 12th km Thessaloniki-Chalkidiki, Thermi, 57001 Thessaloniki, GreecePLiN Nanotechnology S.A., Spectra Business Center 12th km Thessaloniki-Chalkidiki, Thermi, 57001 Thessaloniki, GreeceDepartment of Materials Science and Technology, University of Crete, 70013 Heraklion, GreeceA lot of effort has been dedicated recently to provide a better insight into the mechanism of the antibacterial activity of silver nanoparticles (AgNPs) colloidal suspensions and their released silver ionic counterparts. However, there is no consistency regarding whether the antibacterial effect displayed at cellular level originates from the AgNPs or their ionic constitutes. To address this issue, three colloidal suspensions exhibiting different ratios of AgNPs/silver ions were synthesized by a wet chemistry method in conjunction with tangential flow filtration, and were characterized and evaluated for their antimicrobial properties against two gram-negative, <i>Escherichia coli</i> (<i>E. coli</i>) and <i>Pseudomonas aeruginosa</i> (<i>P. aeruginosa</i>), and two gram-positive, <i>Staphylococcus aureus</i> (<i>S. aureus</i>) and <i>Staphylococcus epidermidis</i> (<i>S. epidermidis</i>), bacterial strains. The produced samples contained 25% AgNPs and 75% Ag ions (AgNP_25), 50% AgNPs and 50% Ag ions (AgNP_50), and 100% AgNPs (AgNP_100). The sample AgNP_100 demonstrated the lowest minimum inhibitory concentration values ranging from 4.6 to 15.6 ppm for all four bacterial strains, while all three samples indicated minimum bactericidal concentration (MBC) values ranging from 16.6 ppm to 62.5 ppm against all strains. An increase in silver ions content results in higher bactericidal activity. All three samples were found to lead to a significant morphological damage by disruption of the bacterial cell membranes as analyzed by means of scanning electron microscopy (SEM). The growth kinetics demonstrated that all three samples were able to reduce the bacterial population at a concentration of 3.1 ppm. SEM and growth kinetic data underline that <i>S. epidermidis</i> is the most sensitive among all strains against the investigated samples. Our results showed that all three AgNPs colloidal suspensions exhibited strong antibacterial properties and, thus, they can be applied in medical devices and antimicrobial control systems.https://www.mdpi.com/2079-4991/12/1/31minimum inhibitory concentrationminimum bactericidal concentrationgrowth kinetics<i>Escherichia coli</i><i>Pseudomonas aeruginosa</i><i>Staphylococcus aureus</i> |
| spellingShingle | Varvara Platania Alexandra Kaldeli-Kerou Theodora Karamanidou Maria Kouki Alexander Tsouknidas Maria Chatzinikolaidou Antibacterial Effect of Colloidal Suspensions Varying in Silver Nanoparticles and Ions Concentrations Nanomaterials minimum inhibitory concentration minimum bactericidal concentration growth kinetics <i>Escherichia coli</i> <i>Pseudomonas aeruginosa</i> <i>Staphylococcus aureus</i> |
| title | Antibacterial Effect of Colloidal Suspensions Varying in Silver Nanoparticles and Ions Concentrations |
| title_full | Antibacterial Effect of Colloidal Suspensions Varying in Silver Nanoparticles and Ions Concentrations |
| title_fullStr | Antibacterial Effect of Colloidal Suspensions Varying in Silver Nanoparticles and Ions Concentrations |
| title_full_unstemmed | Antibacterial Effect of Colloidal Suspensions Varying in Silver Nanoparticles and Ions Concentrations |
| title_short | Antibacterial Effect of Colloidal Suspensions Varying in Silver Nanoparticles and Ions Concentrations |
| title_sort | antibacterial effect of colloidal suspensions varying in silver nanoparticles and ions concentrations |
| topic | minimum inhibitory concentration minimum bactericidal concentration growth kinetics <i>Escherichia coli</i> <i>Pseudomonas aeruginosa</i> <i>Staphylococcus aureus</i> |
| url | https://www.mdpi.com/2079-4991/12/1/31 |
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