a non-chemical (or at least chemical precursor-free) method is pulsed laser ablation in liquids. This method may provide clean nanoparticle colloids for medical and catalysis application, see:

http://youtu.be/J0vZgQFDyjo

Yes, just fire a femtosecond pulse IR laser on a piece of gold and younwill get gold nanoparticles. A purely physical method.

PS: apologies for his outburst of flippancy. The chemical method (or so called Turkevich method) is probably the easiest method to synthesise gold nanoparticles.

Biosynthesis is safest and rapid procedure for synthesizing gold and silver nanoparticles

The purpose of synthesis of the nanoparticles is important. If it is for cell interaction studies. Biosynthesis is proved to be best method for the synthesis. But for other application chemical method is preferable.

Are right roy, many atimes that what usually happened in biosynthesis method.I think you can try and get this paper becouse must method provide low amount of gold nanoparticle. but facile method in the synthesis GNPs from concentrated chloroauric acid by adding sodium hydroxide and controlling the temperature, this method will give you best and uniform size of GNPs InshaAllah.

see:"Facile synthesis of concentrated gold nanoparticles with low size-distribution in water: temperature and pH controls" byChunfang Li, Dongxiang Li*, Gangqiang Wan, Jie Xu and Wanguo Hou. Nano research letters Journals.http://www.nanoscalereslett.com/content/6/1/440

i agree with sathish.focus on application part.

some reports telling using citric acid and cow urine (biological synthesis), we will get monodispersive particles

a non-chemical (or at least chemical precursor-free) method is pulsed laser ablation in liquids. This method may provide clean nanoparticle colloids for medical and catalysis application, see:

http://youtu.be/J0vZgQFDyjo

For examples of application, see also:

http://www.uni-due.de/barcikowski/fothem.htm

I need to study the interaction of gold nanoparticles with IgG..

I tried chemical method but it didn't give me pure sample..

can somebody please provide a way to attach an IgG molecule between 2 gold nanoparticles with a greater accuracy???

Best one is using auric chloride and trisodium citrate, to attach antibodies use thiol or EDC chemistry.

With plants extracts, or with biomass coul be from: plants or microorganims

Biosynthesis is the easy method.....

thank you for your Question

Biosynthesis is best

So there is the standard citrate reduction method. Especially since you asked for chemical method, lasers are awesome but not everyone has one.

All you need is HAuCl4 readily found at either VWR or Sigma.

Sodium Citrate and Tannic acid To achieve different sizes you just have to vary the amount of Tannic acid.

Hayat, M. A. Colloidal Gold: Principles, Methods and Applications, 1989; Vol. 1.

the resulting AuNP's will be capped with citrate which is not a very good ligand for gold so it is easily exchanged for what ever ligand you want. thiols are pretty good ligands if you can couple your IdG to something with a thiol that will exchange very reliably

this method is very similar to the "biosynthesis method" but in my experience this gives much better size distribution

Otherwise there are some lithography methods that are not as easy.

Chemical methods are mainly employed (the Turkevich route) for gold colloids:

February 18th, 2016 Metal colloids - their preparation, application and characterization

https://www.brainshark.com/malvern/vu?pi=529368070&b=1&tx=120486&c1=22

Stephan highlights a route similar to the Bredig electric arc method (1898).  Slides 34 and onwards in the above.