Team:Concordia/Demonstrate/Synthesis Results
NANOPARTICLE SYNTHESIS RESULTS:
Plant Synthesis: Aloe Vera
Triangular Gold Nanoparticles(10-100 nm) Synthesized using Aloe Vera Extract.
Optimal variables:
1 mM HAuCl4 solution with 40%(v/v) Aloe Vera Extract.
The colour change to purple of the solution when mixing aloe vera extract and chloroauric solution suggests the successful formation of gold nanoparticles. The colour change only suggests nanoparticle formation and further steps have to taken to actually characterize the nanoparticles synthesized.
We had initially expected the nanoparticles to be triangular in shape and to be around 100 nm in size. Upon inspection, we found that the nanoparticles were a variety of sizes from 10 to 100 nm and were not exclusively triangular. We also found that there was a film around the nanoparticles, which we learned was potentially organics from our extracts.
An Energy-dispersive X-ray spectrogram (EDS) was obtained for our samples to confirm that they were indeed gold. High peaks for copper and carbon are a result of the grid used in the microscope. The peaks containing gold (Au) are a confirmation that the nanoparticles are made of gold.
A maximum absorbance at approximately 530 nm confirms the presence of gold nanoparticles, which was most strongly displayed by nanoparticles that were synthesized using an aloe vera extract that was 40%(v/v) in solution. This result further confirms the presence of gold nanoparticles.
Conclusion:
Based on the images presented above, we can conclude that we have successfully synthesized gold nanoparticles utilizing chloroauric acid and aloe vera extract. The expected triangular shapes were observed in some of the synthesized nanoparticles but not all of them and the size ranges was far from the 100 nm that were expected. The drop-rate of the chloroauric acid into the aloe vera extract can be controled more efficiently and perhaps this would yield better results. After testing different concentrations of chloroauric acid and different aloe vera to chloroauric acid ratios we found that the optimal parameters for the synthesis of these gold nanoparticles is 1 mM chloroauric acid with 40% (v/v) Aloe Vera extract.
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Plant Synthesis: Garlic
Conclusion:
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Plant Synthesis: Cabbage
Spherical Silver Nanoparticles (5-30 nm) Synthesized using Cabbage Extract
Conclusion:
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Chemical Synthesis: Martin Method
Spherical Silver Nanoparticles (1-10 nm) Synthesized using the Martin method
The Martin method of synthesis was used to create gold nanoparticles ranging in size from 1-10nm. The colour change from clear to dark red indicates the formation of our nanoparticles.
Individual nanoparticles cannot be observed through a typical light microscope because of their small size. Once synthesis of our nanoparticles was complete, we brought samples to a Transmission Electron Microscope (TEM) to observe our nanoparticles. Above is one of the images from the TEM. The nanoparticles were all spherical in size and fell into our expected range of 1 - 10nm. Most of the nanoparticles were around 5 nm in size, which is optimal for our nanoshell attachment method.
One method for confirming the presence of our nanoparticles involved measuring the absorbance of our samples using uv-vis spectroscopy. Gold nanoparticle synthesis appears to be successful from this UV-vis data. We were expecting a peak at 513±3nm and obtained a peak at 511 nm.
One method for determining the size of nanoparticles involves the use of dynamic light scattering (DLS). This method measures the size of nanoparticles based on the water molecules surrounding the nanoparticles. This hydrodynamic size confirms the diamter of our nanoparticles. Accordind to our DLS data, most of the nanoparticles synthesized through the Martin Method were 3nm or 5nm. This falls into our expected range of 1-10nm.
Conclusion:
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Chemical Synthesis: Turkevich Method
Conclusion:
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