Gold Nanostar Synthesis with a Silver Seed Mediated Growth Method
January 15th, 2012
We synthesized star shaped gold nanostars using a silver seed mediated growth method. The diameter of the nanostars ranges from 200 to 300 nm and the number of tips vary from 7 to 10. The nanoparticles have a broad surface plasmon resonance mode centered in the near infrared.
The overall goal of this procedure is to synthesize gold nano stars using silver seed mediated growth method. This is done by first synthesizing the silver seeds and then putting them into the growth solution, which finally generates the gold nano stars with the size of 200 nanometers. The advantage of using silver seeds over gold is to synthesize gold nano stars with smaller cores and longer picks with high yield and stability.
For an experiment, you'll need six vials, two steering magnets, six ULA powders of gold chloride, silver nitrate, sodium hydrate, sodium citrate, ascorbic and ctap deionized, water timer, and pipettes. You'll also need the steering plate and the scale for mixing, warming, and weighing different compounds, and then aluminum foil can be used as an option for isolating the solution from light. First step is to prepare cellular sets by taking sodium citrate, cellular nitrate, and sodium boal hydrate.
Take sodium citrate and use a scale to measure weight. Take 10 milliliters of deionized water, Mix them together and check the vial by hand to dissolve the solution and receive the desired concentration. Label the vial with the necessary information.
Prepare a stock solution of cellular nitrate by taking an arbitrary mass and mixing it with 10 milliliters of di water. Calculate molarity of the solution and keep it isolated from light using the foil or by pulling it in the dark place. Prepare a sodium boal hydrate.
Place the vial in a bucket with ice and then keep it in a refrigerator. Do not check the solution with the vortex. Sir, start taking time.
The freshly made solution will be used in 15 minutes, which is enough time to cool it down by following this diagram. Take a vial, place it on a steering plate, put a magnet in it, and 10 milliliters of water. Add the calculated amount from the stock solution of cellular nitrate to make its final concentration equal to 2.5 times 10 to the minus four molar.
Start steering the solution. Add sodium citrate of the solution. After 15 minutes, take the sodium boal hydrate out of the refrigerator And editing to the solution.
With a single quick stroke, the color will immediately turn yellow, steer it for five minutes. After that, stop steering, take out the magnet and keep the vial isolated from light. Do not close the vial.
Let it stay for two hours before using. These are the images of silver seeds obtained by a transmission electron microscope scope. The next step is a preparation of growth solution followed by the silver seed edition.
By following this diagram, prepare a desired concentration of a scic acid and 10 milliliters of a concentrated solution of gold chloride. Set the temperature of the plate at 30 degrees Celsius. After it becomes hot, place a vial on it with 20 milliliters of water and prepare set up solution.
Immediately place a magnet into the vial and start steering. After CA is completely dissolved and the solution becomes transparent, turn off the hot plate but keeps steering. Now you'll need cellular nitrate, gold chloride as cor cases and silver seeds.
To finalize the synthesis. First take already prepared stock solution of cellular nitrate and add the calculated amount into the set up solution. Start taking time after one minute Ed.Calculated volume of gold chloride stock solution.
After one more minute, ed Acobi, the solution will turn colorless in 20 seconds, eight 50 microliters of silver seeds. The solution will start to turn blue and then brown. Isolate the nanoparticle solution from the, and keep it for 24 hours to let them grow.
For higher chance of getting good nano stars, you can make more than one solution at the same time. Sometimes solar seats may obtain the wrong color or its surface can become dirty, which is usually caused by the magnet not being very clean. In these cases, you have to prepare the seed solution again while making the growth solution.
If you do not start steering right after adding sit up powder to the water, then SITA will form a gel on the bottom, which is then very hard to remove. Before using these gold nano stars for imaging spectroscopy or some experiment, you should wash them to remove ctap from the solution. CTAP may crystallize at room temperature to dissolve the crystals.
Hit the solution up to 30 degrees Celsius or use hot tap water until the crystals disappear. Put the solution in centrifuge, tubes and Sade for two minutes. Centrifuge solution for five minutes At 730 RCF, the nano stars will accumulate on the wall of the tube, remove as much of the solution with the pipette, taking care of not removing the nanoparticles at Dior and ADE for two minutes.
Repeat the washing process two more times at 460 and 300 and A-T-R-C-F for three minutes. Now the nanoparticles are ready for imaging spectroscopy, and experiment. The images were obtained using a scanning electron microscope.
This figure shows the absorption spectra of gold, nano stars and cellular seats. After watching this video, you should be able to synthesize gold nano stars with high yield instability. Size of 200 nanometers.
Number of tips vary from seven to 10, and the surface plasma resonance centered in near infrared. These nano stars can be used in photothermal ablation, drug delivery, and in many other biomedical applications.
View the full transcript and gain access to thousands of scientific videos
Overview
This study focuses on synthesizing star-shaped gold nanostars using a silver seed mediated growth method. The resulting nanostars have diameters ranging from 200 to 300 nm and feature 7 to 10 tips, exhibiting a broad surface plasmon resonance mode in the near infrared.
Key Study Components
Area of Science
- Nanotechnology
- Materials Science
- Nanoparticle Synthesis
Background
- Gold nanostars are nanoparticles with unique optical properties.
- Silver seed mediated growth allows for the creation of nanostars with smaller cores.
- These nanoparticles have applications in biomedical imaging and therapy.
- Understanding their synthesis is crucial for optimizing their properties.
Purpose of Study
- To synthesize gold nanostars with controlled size and morphology.
- To explore the advantages of using silver seeds in the synthesis process.
- To enhance the stability and yield of the synthesized nanoparticles.
Methods Used
- Synthesis of silver seeds followed by incorporation into a growth solution.
- Utilization of various chemical reagents including gold chloride and silver nitrate.
- Control of reaction conditions such as temperature and mixing.
- Isolation of the solution from light using aluminum foil.
Main Results
- Successful synthesis of gold nanostars with diameters of 200-300 nm.
- Nanostars exhibited 7 to 10 tips, enhancing their optical properties.
- Broad surface plasmon resonance mode was observed in the near infrared.
- High yield and stability were achieved using silver seeds.
Conclusions
- The silver seed mediated growth method is effective for synthesizing gold nanostars.
- Nanostars produced have potential applications in various fields.
- Further optimization of synthesis parameters could enhance their properties.
