How to Synthesize Gold Nanoparticles in Aqueous Phase
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- Опубліковано 6 жов 2024
- In this method, HAuCl4 is used as a gold precursor, trisodium citrate is used as a reducing agent. Trisodium citrate also helps to stabilize the gold nanoparticles electrostatically. If you like to aggregate these nanoparticles, you can add sodium chloride. This will help you to aggregate gold nanoparticles irreversibly. The method is simple.
Acknowledgements:
Bigioni's lab
Department of Chemistry, The University of Toledo
gold is also AuKCaYZr, or “Oh Kaiser”, as 1:3 K:Ca or 1:1 Y:Zr, welded and hammered together...
In my case it didn't work. I think there is a lack of information in the video. Missing to add an element that corn syrup or maltodextrine.
Hi, thank you very much for posting your video. I have been having so much trouble with this simple synthesis I thought I'd share my tale (80% due to my own inexperience and mistakes). I prepared the gold salt from aqua regia but did not evaporate to dryness / remove unreacted nitrates from the solution. When I tried your ratio and boiling solution with this still acidic solution, I did see some solid precipitate at the bottom of the solution (absorbance began at ~513 nm, but was very broad and the solution was mostly clear). After purifying the gold salt and letting it sit in a vacuum oven, I tried another method with a 2.12:1 Na3citrate:gold salt ratio at 80C and did not observe any nanoparticle formation even with the 6pH solution resulting from the presence of chloroauric acid without any leftover aqua regia. Today I will be trying the boiling solution 7.76:1 ratio synthesis and will hopefully be amending this comment with successful results. [My current lab largely has nothing to do with synthesis let alone inorganic nanoparticle synthesis but... new project ideas require these]
We haven't studied the effect of stirring rate on the nanoparticle size. However, if we get the ruby red color at the end, it is very likely that the synthesized nanoparticles are mono-dispersed.
there other publications stating that they have achieved over 100 nm,
the process was much longer and they kept the solution from evaporating by adding more auhcl4
Nice work!
Solid white object rotating at the bottom of the beaker is a magnetic stirrer.
The average diameter of these gold nanoparticles is roughly 13 nm. Majority of them are spherical in shape. Few of them are triangular and others are like rod in shape. We can get < 10% polydispersity in nanoparticle size distribution.
The reference paper: Turkevich, J.; Stevenson, P. C.; Hillier, J. Discussions of the Faraday Society 1951, 11, 55
See other videos to have better understanding on nanoparticle shapes and sample preparation.
Hi friend :) Im glad that finding your comment...
Im strugguling with the colloid making process cuz of the high temperature...
I had the thought yestarday that should be other way around witch one dont require heat... Can you share the name of the process with me to look into it...? I can reach ruby color ,only purple...and stucked with it for the past months...so fustrating
I see you have used the heat to make the Gold nanoparticles. However, there are methods which requires it be done under 4 degree Celsius (which is what I am using, for no particular reason).
1) How different are these two methods from one another, especially in terms of temperatures usage?
2) Where do you store them using this heating method?
3) Since not all the particles in the solution are Gold nanoaparticles, how do you suggest to purify them (4 nm sized ones)?
Very much looking forward to hearing from you.
Thank you,
Nakul
Dear Nakul,
During nanoparticle synthesis, temperature is used to control kinetics.
You mentioned, you are using low temperature. Generally, low temperature produces small nanoparticles called nanoclusters(~ 1-3 nm). High temperatue produces large nanoparticles (~5- 15 nm).
I store the synthesized gold nanoparticles (shown in the video) under ambient conditions. These nanoparticles are stable in room temperature.
Since, we are mixing gold salt, water, and sodium citrate in the presence of heat (no additional material). All the particles in the solution are gold nanoparticles.
chakraprasadjoshi thank you so much for your response. So, using the method I'm using (low temperature), all the particles are GNPs?
Can I also ask a final question, how do you make sure the antibodies you use for conjugation is oriented in a specific manner such that it's binding site to the receptor is not blocked. My guess is to use polyethylene glycol (PEG) or other linkers. OR you suggest antiBodies be attached directly without any linkers. What's your advice on this?
Thank you once again,
Regards,
Nakul
One way is ---
By phase transferring into toluene (using cationic surfactants) and then ligating with suitable ligands such as oleylamine and finally precipitating with non-solvents (ethanol), you should be able to get nanoparticles in dry form. Please let me know if you still have difficulty.
Can you explain this in detail pleas
Dear Asila,
Nanoparticle synthesis is shown in detail in the video. Please let us know where you got confused.
@@chakraprasadjoshi first of all thank you for reply and for the video my question is how can i purify this NP and if it is possible to know the concentration of the pure solution for example can i make known concentration in D water to use it for other steps
Hi Asila,
May be you need to watch the video to get an idea of nanoparticle concentration in the solution. Please pay attention to the numbers/calculations shown in the Video: ua-cam.com/video/J-B3n02DOOs/v-deo.html to have an idea.
Hello, we would like to replicate this experiment for a school project. Could you please tell us the methodology with specifics? (Temperature, etc)
Dear Reggina,
Synthesis is straightforward. Only thing you have to do is boil and stir the reaction mixture. Steps of reagent addition, molarity and volume of ingredients used are shown in the video. You could do nanoparticle synthesis with less volume of reagents (than used in the video) while maintaining the same ratio. Give a try. Please let me know if you still have difficulty.
gold [79] = iodine metal [53] + iron [26]; purple solution [iodine]; red solution [iron or ferrous sulfate];
Thanks for your comment. Could you please post the reference paper so that we can have better idea. Thanks
Hi would it be ok for me to drink this in small amounts like a tincture ? If so how do I do that?
can i know what method if i use gold(III) chloride trihydrate with hydroxyethyl cellulose?..the process was we use micropipette and heated with stirring machine. liquid chemical method or turkevich method??
Great learning Dr. Chakra, please let me know the temperature you maintained over periods of synthesis, and magnetic bar rotation speed. Many thanks, Raj.
During nanoparticle synthesis we have to boil the solution (temperature ∼ 100 °C) with a stirring rate of ∼ 700 rpm (depends on stirrer size and/or shape). Hope this helps.
chakraprasadjoshi Many thanks Dr. Chakra, You are really helpful for society. Sincerely, Raj,
Hey, do you know the concentration/number of gold nanoparticles you got at the end in that 330mL solution, I need to put the gold nanoparticles in a hydrogel, do you know how ?
Hi Dr. Chakra. Thank you for your great teaching.
You said if I want to aggregate these nanoparticles, I can add sodium chloride. Can you give me some details for the method?
Dear Vu,
Please, add some NaCl powder or solution directly to the nanoparticle solution to observe the aggregation effect.
Thanks Mr. Chakra! Did you ever try to form specific shape by this way yet? Like sea urchin, star.. shape? And can i ask what are the parameters for them?
No, we did not study specific shape formation by this way.
Hello sir!
I have one doubt. My solution is remaining pale purple at the end not changing to wine red. Can you please explain any probable reason for this?
Dear Aosheen,
It is difficult for us to tell exactly what could have gone wrong in your nanoparticle synthesis. However, pale color may indicate the presence of insufficient reducing agent in the system.
What ph should be maintained during synthesis?
I read that at ph>7 it gives smaller np's
Dear Ashneet,
You may be right. In fact, nanoparticle synthesis is pH sensitive. Depending on pH of the reaction solution, different size and shape particles can be synthesized.
can you explain why Sodium chloride helps to make aggregate gold?
Dear 박승진,
Sodium chloride screens the surface charge of these nanoparticles. As a result, nanoparticles come close to each other and aggregate.
Once you reach the ruby red color turn the heat off
Can the nanoparticles be used as catalyst in the solution phase itself?
Dear Mansi,
It is possible to use nanoparticles as a catalyst in the solution phase that might depend upon a system type.
@@chakraprasadjoshi Thank you. Also what colour is the solid nanoparticle after separation. Can it be black?
Dear@@mansidubey8759, dry powder of nanoparticles appears black.
thank you
Does this have extreme positive effects on the human body and can keep you cured from most diseases? even Cancer?? I heard something about it, is very hard to succeed but the effects are supposed to enhance the body greatly, even prolong life.
I dont know everything about this but is this part of esoteric knowledge and if so, are the higher powers keeping this from us/the public and academics??
My dear, Raiken Xion.
The illuminati is indeed keeping this information from us, mainly because they want the gold needed for it to use it for their gold plated houses and jewellery.
Yours faithfully,
Mister the guy
What is the solid object rotating at the bottom??
It's a magnetic mixer
Hello Mr. Chakra, I was wondering if you knew the specific ratios of chemicals if we wanted to make nanoparticles of roughly 15nm in size. Thank you.
I Know
Sir how to prepare o.5mM aq. gold chloride solution
Good day! Did you adjust the pH of your trisodium citrate solution? If yes, what was the pH? Thank you.
Although 38.8 mM solution of aqueous trisodium citrate would maintain some pH, we didn't adjust the pH during the reaction.
Can I ask that I want to estimate the concentration of the gold nanoparticles in the solution after synthesis, how can I do that?
Hello Codie2002,
Please see the video ua-cam.com/video/J-B3n02DOOs/v-deo.htmlsi=h6tpQc10yi6Reh-q to have some idea about the concentration of gold nanoparticles
Which water to use in these preparation
thanks for your effort may I ask about stained glass if I put a layer from that nano gold on glass cup and heating to 600 C will give me a bright gold layer or not?
I am following the turkevich method( Citrate reduction) in my project.
Usually Cloroauric acid( HAuCl4) is reduced by trisodium citrate.
I wanted to know that if Gold chloride( AuCl3) can be reduced IN THE SAME WAY to form gold nanoparticles?
Also what are the parameters(concentration,amount) required to make HAuCl4 from AuCl3?(if the previous cannot be done)
Hi Zareef,
In principle, it is possible to use AuCl3 instead of HAuCl4. However, variation in pH, solubility, & other factors might cause difficulty to get desired size nanoparticles with high degree of monodispersity.
okay thanks.
could you mention the amounts and concentration of AuCl3 and HCL required to make lets say 1grm of HAuCl4?
Hello, I have tried it with Aucl3 the solution did change colour but the colour was very deep.To get a more reddish colour(smaller particles) what can be done?
Sir I have only 1gm so how to make batches with concentration
I tried to synthesize Au (
Hi Mangai,
The citrate reduction method shown in the video produces nanoparticles of size ~ 10 nm. If you want to get smaller size NPs, you may need to vary the concentration of citrate or use other literature methods.
Sir, is the heating continued all over the process?
Dear Payal,
Yes, heating continued to the end.
Dear
Could you please tell us
1- how many grams from Gold should be dissolved in royal water.
2- and how many ML from gold solution use
3- how many ML from distilled water use.
4- how many ML from citric acid use.
Thank you so much dear
200 mL distilled water. ..... 12 drops sodium chloride solution....... 24 drops Kare Syrup 50-50 distilled water solution...20 drops gold chloride 1% solution
Put it in microwave three minutes
Optional. This is a capping agent. Add 1 teaspoon gelatin solution into one cup distilled water.... then add 2 teaspoons of this capping Agent into your colloidal gold mix. This will allow it to get to your stomach without any salt or acid affecting the growth of the particle size.
40 ppm 500 mL distilled water.. gold chloride 12 drops... Karo syrup 12 drops...sodium carbonate solution 12 drops...Put it in the microwave three minutes.
Hello,
I prepared gold nanoparticles by this (Turkevich) method. Then I add safranine T and solution change colour from red to blue-violet. I think there was aggegation. BUT I have problem - after a few minutes measuring cuvette remained dirty. How I can clean cuvette, please? I need to dissolve gold nanoparticles aggregate and clean the cuvette glass.
Thank you for reply.
Hi Roland,
Please use aqua regia to clean your dirty cuvette. Aqua regia will definitely remove those aggregated gold nanoparticles. By the way, be careful while using aqua regia.
Cuvett can be easily cleaned with a bruch and soap
You can do the same thing in a microwave for three minutes
wow, this method dont use sodium borohydride. I am wondering whether Au nanoparticles is in solid state.
Dear Loc,
Au nanoparticles are dispersed in water. These nanoparticles are not stable in solid state.
(also see this video ua-cam.com/video/J-B3n02DOOs/v-deo.html)
Do you get monodisperse gold nanoparticles with this protocol?
Dear Hữu,
Very small number of triangular and other shaped nanoparticles can be observed. These non-spherical particles seem to be unavoidable with Turkevich method. Otherwise you do get monodispersed nanoparticles. See the electron micrograph of these nanoparticles in the same video.
How can we precepetate this gold again as a yellow or brown
Dear Aymane,
You could add salt (e.g., NaCl) to precipitate these nanoparticles.
@@chakraprasadjoshi
What do u mean by e.g and why he always precepetate as white powder and thank u
Always use distilled water
Better purified.
Why are you keeping the temperature High.....I mean Hot?
Hi Yisehak,
high temperature is required to reduce Au(III) ions into Au(0).
Thanks bro.
Is this monoatomic gold?
Yes, it is a collection of monoatomic gold, Majji Mantra.
why is sodium citrate used in this method?
Dear Gerard,
Sodium citrate is used here to reduce metal ions and to stabilize nanoparticles.
Hello Dear chakraprasadjoshi
I have followed your method and I think that I could synthesis gold nanoparticle successfully. to characterize the Gold NPs synthesized I measured their UV-Vis absorption. but, unlike your maximum absorbance which was around 1.0, my Gold NPs synthesized maximum absorbance is around 0.16 !. can you please guide me to whats happends? I want to my particle size be same yours( ~10 nm). is it done or no?
I will appreciate if help me.
Dear Hossein,
Don't worry about the maximum absorbance. The UV-vis spectrum shown in the video was normalized.
thanks a lot chakraprasadjoshi
can you please say that your what was your GNP size?
It was roughly around 10 nm.
Hello dear chakraprasadjoshi
by followed your method, I have synthesized my gold nanoparticles and after 4 mounts, I measure them by DLS. this analysis showed that my average size is around 40 nm and also near this particle size distribution, I have another particle size distribution which showed that my average size is around 200 nm!
can you please guide me that what happened?
I can send to you my result to show you.
please let me have your email address to send to you.
my email is: alishaharad@gmail.com
Regards,
Hi Hossein,
Not sure what caused your nanoparticles (NPs) to grow. There are several possible reasons for it. However, Please measure the NP size using TEM. TEM would provide accurate NP size estimation than the DLS measurement. This would confirm your NPs indeed grew from the original size.
Slow down the rotation and it won’t do that
What is aq?
Dear Gumus,
aq = aqueous
How can you say that it is stable? can we store it in a freezer?
Dear Arren,
Under ordinary conditions citrate stabilized gold nanoparticles (AuNPs) are stable. We have seen the vibrant red color of the citrate AuNPs persisting for many months. You may store these AuNPs safely up to 4 °C in a freeze.
It's a mistake that I put my synthesized AuNPs in a freezer. When I checked it it's already late coz it's aggregated. Have you tried doing the biofunctionalization of AuNP and thiol probe?
Dear Arren,
We have not done any work related to biofunctionalization of AuNP.
Thank you, sir.
I tried this synthesis, but it failed... I followed the protocol, HAu boiled, I added the sodium citrate, the solution went black, but then returned to a transparent solution, and I had a weird black substance floating...
Does someone have an idea what went wrong ?
Hi Laurene,
As you mentioned, your solution went black and then became transparent.There may be several reasons for this issue. By the way, did you maintain the concentration of Au³+ and citrate ions as described in the video? Also, did you clean your glasswares properly?
chakraprasadjoshi
Hi, I did respect the concentrations and the solutions were made by laboratory staff. I washed the glassware with distilled water, but maybe it wasn't enough...
@@chakraprasadjoshi Sir, i was undergoing the same thing likes skrywer did. Anyway Sir how long were you Boiling and Steaming in the first step??? Thanks in advance Sir
Dear @@muhammadhafidavif3202, just boiling for 2-4 minutes is good enough. Thanks
Can you PEGylate the citrate capped NP?
Dear N Soni,
You can add PEG coating around these citrate AuNPs. We have done some experiments with PEGylation.
@@chakraprasadjoshi thanks. Do you have any reference paper? Also what's the long term stability of citrate capped Au NP? How long can you state at say 4°C before they collapse?
Dear N Soni,
Citrate AuNPs are very stable (>> 1 year) in the aqueous solution but may collapse when the solution is frozen.
How to prepare aq.38.8mM trisodium citrate solution
Dear Akshay,
How much solution you want to prepare?
I have only 1 GM Chloroauric acid so according to that
Dear Akshay,
HAuCl₄.3H₂O (Molecular Weight = 393.83)
To prepare 1 mL of 0.5 mM HAuCl₄.3H₂O solution, please dissolve ~0.197 mg of HAuCl₄.3H₂O in 1 mL of deionized water. Please check online where you will find lots of ideas about how to prepare salt solutions.
chakraprasadjoshi
Is it 0.197 mg or 197 mg?
chakraprasadjoshi
Is it ok to use HPLC water or we must use deionized water only
Synthesizing Gold? This is not and I don't know anyone who is able to do it. Silver yes! What you have here is a Nano Gold suspension. Seeding (tricitrate) should have been done in the 1st step.
You are a Doctor? Just curious...
What will be the nanoparticle size by using your method?
∼ 11-12 nm diameter nanoparticles
Do you have a formulation to build 40 nm diameter nanoparticles?
With some modifications, it’s possible to get 40 nm nanoparticles. There are several reports in the literature. For example, a paper by Jana, N. R., et al. (2001). "Seeding Growth for Size Control of 5−40 nm Diameter Gold Nanoparticles." Langmuir 17(22): 6782-6786 might be useful for you.
Thanks.
chakraprasadjoshi could not find this article online
Dear friends
I have a question: how do you remove the nanoparticles from the solution?
Thank you a lot~~
Hi, you could do phase transfer to remove the nanoparticles from the solution.