Duffy, Brendan

Jaiswal, Swarna

McHale, Patrick

English

Arrow@TUDublin

Technological University Dublin ARROW@TU Dublin Conference Papers Crest: Centre for Research in Engineering Surface Technology 2011-07-12 Effects of β-Cyclodextrin as a capping agent on the antibacterial properties of AgNPs Swarna Jaiswal Technological University Dublin, swarna.jaiswal@tudublin.ie Brendan Duffy Technological University Dublin, brendan.duffy@tudublin.ie Patrick McHale Technological University Dublin, patrick.mchale@tudublin.ie Follow this and additional works at: https://arrow.tudublin.ie/cenrescon  Part of the Biomedical Engineering and Bioengineering Commons Recommended Citation Jaiswal S, Duffy B & McHale P. (2011) Effects of β-Cyclodextrin as a capping agent on the antibacterial properties of AgNPs. 8th International Conference on Nanosciences & Nanotechnologies (NN11) July 12th -15th, 2011, Thessaloniki, Greece This Presentation is brought to you for free and open access by the Crest: Centre for Research in Engineering Surface Technology at ARROW@TU Dublin. It has been accepted for inclusion in Conference Papers by an authorized administrator of ARROW@TU Dublin. For more information, please contact yvonne.desmond@tudublin.ie, arrow.admin@tudublin.ie, brian.widdis@tudublin.ie. This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License 8th International Conference on Nanosciences & Nanotechnologies (NN11)  12-15 July 2011, Thessaloniki, Greece.                      Abstract   Principal Author Details   Author Name: Swarna Jaiswal  Title (Ms/Mrs/Mr/Dr/Prof/Other): Mrs  University: Dublin Institute of Technology,   Department: School of Biological Science  Address: Focas Institute, Centre for Research in Engineering and Surface Technology, Kevin Street,   Dublin 8, Ireland  Phone: +353-1-402-7992  Email: swarna.jaiswal@dit.ie       8th International Conference on Nanosciences & Nanotechnologies (NN11)  12-15 July 2011, Thessaloniki, Greece.   Select contribution:  √   Oral presentation      Poster presentation  Select  Workshop:  Nanomaterials, Nanofabrication, Nanoengineering & Nanoconstruction   Effects of β-Cyclodextrin as a capping agent on the antibacterial properties of Ag NPs  Swarna Jaiswal1,2* ,  Patrick Mc Hale1, Brendan Duffy2 1School of Biological Sciences, Dublin Institute of Technology, Kevin Street, Dublin 8,Ireland 2Centre for Research in Engineering Surface Technology (CREST), FOCAS Institute, Dublin Institute of Technology, Dublin 8, Ireland, swarna.jaiswal@dit.ie  Introduction The persistence of antibiotic resistant bacteria has renewed interest in the use of silver and silver based compounds, including silver nanoparticles (AgNPs), as alternative antibacterial agents. The high thermal stability, low toxicity to human cells and effective broadspectrum antibacterial activity of AgNPs  have been exploited in a range of commercial products. AgNPs can be synthesised in a number of ways, with borohydride reduction of silver salts being the most common. Stabilisation is achieved using capping agents that bind to the nanoparticle surface and improve stability and water solubility, which are essential to prevent aggregation.  Experimental In the present study, silver nanoparticles (AgNPs) were synthesised by reducing silver salts using NaBH4 followed by capping with varying concentrations of β cyclodextrin (β-CD). Synthesized β-CD capped Ag NPs characterized by UV-Vis, FTIR, DLS, and TEM. Antibacterial activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus was determined by the microtitre well method. Cytotoxicity of β-CD capped and uncapped Ag NPs were analysed by Alamar blue test. Results and discussion The Ag NPs were spherical under transmission electron microscopy, whilst dynamic light scattering showed average diameters of capped particles to be smaller (4–7 nm) than their uncapped equivalents (17 nm). FTIR confirmed β-CD binding to the Ag NP surface. This suggests that there are chemisorptions between the CD molecules and Ag NPs via the rim hydroxyl groups. Capped particles demonstrated superior photostability when exposed to intense ultraviolet radiation for 4 h. We have observed interesting effects of β-CD as a capping agent, such as the lowering of the nanoparticles MIC against both Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. The antibacterial activity of all test samples were concentration dependent as moderate inhibition was observed when exposed to lower concentration but increased significantly as the concentration increased. The bacterial growth kinetics was monitored in the presence of different test samples. It was found that the biocidal action of β-CD capped Ag NPs was more efficient at low dose for longer period of time, whereas uncapped Ag NPs were found to diminish killing activities with increased aging time. The results demonstrated that the β-CD capped Ag NPs showed significantly higher (up to 3.5 fold) antibacterial activity (p < 0.05) against all the tested organisms versus uncapped equivalent silver concentrations.  Conclusion Therefore it can be concluded that: • Antibacterial activity of Ag  NPs is affected by the level of CD used as a capping agent • Increased levels of CD lead to higher antibacterial efficacy at lower silver ion concentrations. The influence of β-CD concentration was seen to delay bacterial growth, indicating that a Trojan horse mechanism may be occurring owing to bacterial carbohydrate affinity, thereby enhancing silver ion absorption.    

Effects of β-Cyclodextrin as a capping agent on the antibacterial properties of AgNPs

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Effects of β-Cyclodextrin as a capping agent on the antibacterial properties of AgNPs

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