Name: synthesis of multi-walled carbon nanotubes modified with silver nanoparticles and evaluation of their antibacterial activities and cytotoxic properties
Uploaded: 2018-05-10T12:30:00
Description: Watch this Scientific Journal Video about Synthesis of Multi-walled Carbon Nanotubes Modified with Silver Nanoparticles and Evaluation of Their Antibacterial Activities and Cytotoxic Properties at JoV

This study was supported by Chung-Ang University Research Grants (2016) and by the Nano-Material Technology Development Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science and ICT (No. 2017M3A7B8061942).

1. MWCNT Oxidation
<ol>
	<li>Measure 30 - 50 mg of MWCNT into a 50-mL vial. Slowly add 8 mL of a H2SO4:HNO3 solution (90% initial concentration, 3:1 vol/vol) by pipette with 1 mL pipette tips. 
	CAUTION: This preparation must be conducted in a chemical fume hood.
	<ol>
		<li>Allow 30 min for the exothermic reaction to complete.</li>
	</ol>
	</li>
	<li>Sonicate the solution at 60 - 80 &#176;C and 160 W for 1 h until MWCNT settles at the bottom of the vial. 
	CAUTION: The water ...

<ol>
	<li>L&#246;ndahl, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+and+Biological+Properties+of+Bioaerosols.">Physical and Biological Properties of Bioaerosols.</a> Bioaerosol Detection Technologies. , 33-48 (2014).</li><li>Jennings, S., Moran, A., Carroll, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioaerosols+and+biofilms.">Bioaerosols and biofilms.</a> Biofilms in medicine, industry and environmental biotechnology. , 160-178 (2003).</li><li>Flemming, H. -. C., Wingender, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+biofilm+matrix.">The biofilm matrix.</a> Nature Reviews Microbiology. 8 (9), 623-633 (2010).</li><li>Lewis, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Riddle+of+biofilm+resistance.">Riddle of biofilm resistance.</a> Antimicrobial agents and chemotherapy. 45 (4), 999-1007 (2001).</li><li>Doronina, N. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methylobacterium+suomiense+sp.+nov.+and+Methylobacterium+lusitanum+sp.+nov.,+aerobic,+pink-pigmented,+facultatively+methylotrophic+bacteria.">Methylobacterium suomiense sp. nov. and Methylobacterium lusitanum sp. nov., aerobic, pink-pigmented, facultatively methylotrophic bacteria.</a> International Journal of Systematic and Evolutionary Microbiology. 52 (3), 773-776 (2002).</li><li>Seo, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibacterial+activity+and+cytotoxicity+of+multiwalled+carbon+nanotubes+decorated+with+silver+nanoparticles.">Antibacterial activity and cytotoxicity of multiwalled carbon nanotubes decorated with silver nanoparticles.</a> International Journal of Nanomedicine. 9, 4621-4629 (2014).</li><li>Chen, X., Schluesener, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanosilver:+a+nanoproduct+in+medical+application.">Nanosilver: a nanoproduct in medical application.</a> Toxicologyletters. 176 (1), 1-12 (2008).</li><li>Singh, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanotechnology+in+medicine+and+antibacterial+effect+of+silver+nanoparticles.">Nanotechnology in medicine and antibacterial effect of silver nanoparticles.</a> Digest Journal of Nanomaterials and Biostructures. 3 (3), 115-122 (2008).</li><li>Morones, J. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+bactericidal+effect+of+silver+nanoparticles.">The bactericidal effect of silver nanoparticles.</a> Nanotechnology. 16 (10), 2346 (2005).</li><li>Martinez-Castanon, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+antibacterial+activity+of+silver+nanoparticles+with+different+sizes.">Synthesis and antibacterial activity of silver nanoparticles with different sizes.</a> Journal of Nanoparticle Research. 10 (8), 1343-1348 (2008).</li><li>Lok, C. -. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silver+nanoparticles:+partial+oxidation+and+antibacterial+activities.">Silver nanoparticles: partial oxidation and antibacterial activities.</a> JBIC Journal of Biological Inorganic Chemistry. 12 (4), 527-534 (2007).</li></ol>

Here, we report a simple method for the preparation of MWCNTs with deposited Ag nanoparticles. This silver-containing nanomaterial demonstrates substantial antibacterial activity and minimal potential for uncontrolled absorption of silver nanoparticles in the body. We demonstrate that 30 &#181;g/mL of synthesized Ag-MWCNTs is an effective level of antibacterial activity against Methylobacterium spp. with negligible cytotoxicity to mammalian liver cells. Though additional improvements and biosafety assessments fo...

The ultimate goal of this study is to make environmentally friendly antibacterial nanomaterials that can inhibit the growth of bacteria that form biofilms. These antibacterial nanomaterials have the potential to overcome the toxicity and antibiotic resistance problems of commonly used chemicals or antibiotic chemical compounds. A biofilm is a hydrated extracellular polymeric substance (EPS) that is composed of polysaccharides, proteins, nucleic acids, and lipids1,2. Biofilms prevent the intrusion of foreign substances and help bacteria grow vigorously3,4. Biofilms cause odor and chronic infectious diseases5,6. Methylobacterium spp., for example, grows by adhering to places where water is always present or where it is difficult to ensure bacterial eradication on a continual basis, such as air conditioner heat exchangers, shower rooms, and medical devices. These types of biofilms cause odor and chronic infectious diseases5,6.
Typically, chemicals or antibiotic chemical compounds are used to inhibit the growth of bacteria that form biofilms. The emergence of antibiotic resistant bacteria and concerns about in vivo safety of chemicals are driving the need to develop new materials to prevent the formation of biofilms and to inhibit the growth of bacteria.
In this study, antimicrobial nanomaterials are synthesized that are free from antibiotic resistance and toxicity. Silver is a well-known antimicrobial substance, and recent developments in nanoscience and nanotechnology have led to active research into the antimicrobial effects of metal nanoparticles7,8. Recent studies have reported that the small size and high surface-to-volume ratio of the nanoparticles result in increased antibacterial activity9,10,11.
The nanomaterials presented herein combine silver nanoparticles with increased antimicrobial properties and carbon nanotubes with a high aspect ratio, thereby increasing the surface area per unit volume. The fabricated silver nanoparticle-carbon nanotube composite exhibits substantial antimicrobial properties and minimal toxicity to human and animal cells. The synthetic processes in previous studies use hazardous reducing agents such as NaBH4, formamide, dimethylformamide, and hydrazine. The process is complicated, dangerous, and time-consuming. The synthetic process reported here uses ethanol as a significantly less hazardous reducing agent.
The inhibition zone and minimum bactericidal concentration (MBC) for the Ag-MWCNTs were measured; Live/Dead and Trypan Blue assays were used to measure toxicity and antibacterial properties. Minimum inhibitory concentration (MIC) and mitochondrial toxicity (MTT) assays were not performed due to the unusual color of the carbon nanotubes which would have interfered with the assays. Finally, the minimum concentration to prevent the growth of Methylobacterium spp. without affecting mammalian cells was determined.

<table>
	<tbody>
		<tr>
			<td>0.1 N silver nitrate</td>
			<td>SIGMA-ALDRICH</td>
			<td>1090811000</td>
			<td></td>
		</tr>
		<tr>
			<td>Carbon nanotube, multi-walled</td>
			<td>Tokyo Chemical Industry Co., LTD</td>
			<td>308068-56-6</td>
			<td></td>
		</tr>
		<tr>
			<td>R2A agar</td>
			<td>MBcell</td>
			<td>MB-R1129</td>
			<td></td>
		</tr>
		<tr>
			<td>R2A broth</td>
			<td>MBcell</td>
			<td>MB-R2230</td>
			<td></td>
		</tr>
		<tr>
			<td>Methylobacterium spp.</td>
			<td>KCTC</td>
			<td>12618</td>
			<td>from Korea Collection for Type Cultures Daejeon Korea 12618, Daejon, Korea</td>
		</tr>
		<tr>
			<td>LIVE/DEAD Cell imaging Kit</td>
			<td>ThermoFisher SCIENTIFIC</td>
			<td>R37601</td>
			<td></td>
		</tr>
		<tr>
			<td>AML12</td>
			<td></td>
			<td></td>
			<td>from Chungnam University, Dajeon, Korea</td>
		</tr>
		<tr>
			<td>human PBMC</td>
			<td>ATCC</td>
			<td>PCS-800-011</td>
			<td></td>
		</tr>
		<tr>
			<td>TEM</td>
			<td>JEOL</td>
			<td>JEM-2100F</td>
			<td></td>
		</tr>
		<tr>
			<td>XRD</td>
			<td>Rigaku</td>
			<td>D/MAX 2500</td>
			<td>Cu K photon source (40kV, 100mA)</td>
		</tr>
		<tr>
			<td>JuLI Br</td>
			<td>NanoEnTek</td>
			<td>JULI-BRSC&#160;</td>
			<td></td>
		</tr>
	</tbody>
</table>

synthesis of multi-walled carbon nanotubes modified with silver nanoparticles and evaluation of their antibacterial activities and cytotoxic properties

In this study, multi-walled carbon nanotubes (MWCNTs) were treated with an aqueous sulfuric acid solution to form an oxygen-based functional group. Silver MWCNTs were prepared by the reductive deposition of silver from an aqueous solution of AgNO3 on the oxidized MWCNTs. Given the unique color of the CNTs, it was not possible to apply them to the minimum inhibitory concentration or mitochondrial toxicity assays to evaluate the toxicity and antibacterial properties, since they would interfere with the assays. The inhibition zone and minimum bactericidal concentration for the Ag-MWCNTs were measured and Live/Dead and Trypan Blue assays were used to measure the toxicity and antibacterial properties without interfering with the color of the CNTs.

Transmission Electron Microscopy (TEM) images confirm the formation of Ag-MWCNTs (Figure 1A and 1B). Their successful synthesis was confirmed by the change in surface charge. The size of the Ag particles deposited on the MWCNTs was calculated (Figure 1C). The average particle size was approximately 3.83 nm. The XRD pattern of the as-synthesized Ag-MWCNTs is shown in Figure 1D. The pe...

Watch this Scientific Journal Video about Synthesis of Multi-walled Carbon Nanotubes Modified with Silver Nanoparticles and Evaluation of Their Antibacterial Activities and Cytotoxic Properties at JoV

Synthesis of Multi-walled Carbon Nanotubes Modified with Silver Nanoparticles and Evaluation of Their Antibacterial Activities and Cytotoxic Properties

In this study, antimicrobial nanomaterials were synthesized by acidic oxidation of multiwalled carbon nanotubes and subsequent reductive deposition of silver nanoparticles. Antimicrobial activity and cytotoxicity tests were performed with the as-prepared nanomaterials.

In this study, multi-walled carbon nanotubes (MWCNTs) were treated with an aqueous sulfuric acid solution to form an oxygen-based functional group. Silver ...

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