Simple and rapid detection of L-Dopa decarboxylase activity using gold nanoparticles

April 2013The Analyst 138(11)

DOI: 10.1039/c3an00009e

SourcePubMed

So Young ParkDohyoung KwonHyejung MokBong Hyun Chung

Hey,

As much i can understand from the question is that you have synthesized gold nanoparticles from a plant which contains L-Dopa, and that is what stabilizing your gold nanoparticles. now you want to find the concentration of L-Dopa present in gold nanoparticles, right?

if yes, then i would suggest that the plant extract you are using for the synthesis of gold nanopartilces, in a perticular concentration, should be analysed by GC (Gas chromatography), where you will be able to calculate the concentration of L-Dopa present in the exact amount of plant extract. and from that concentration of L-Dopa in gold nanoparicles can be found.

hey Gaurav, u have understood it perfectly correct, I have calculated L-DOPA in my plant extract, but wont the L-DOPA concentration vary, while synthesizing the nanoparticles

Concentration of L-Dopa can vary if the plant you are using has some different types and breeds.

to avoid this, you can check the concentration of L-Dopa after synthesis of AuNPs, which lead you to exact concentration of L-Dopa present in the nanoparticles.

for this you can centrifuge the AuNPs at very high rpm and check supernatent by GC again, (make sure that supernatent contains no NPs as it can damage column). after analyzing supernatent, if any L-Dopa present then you can substract it from the concentration of L-Dopa in plant extract and find the L-Dopa used in AuNPs.

you can make couple of batches by varying concentration of L-Dopa in solution and see if its concentration varies in AuNPs or not.

if you want to vary the concentration of L-Dopa, as it is natural product you can not vary it in the plant extract it self. but you can vary its concentration for your gold nanoparticle synthesis.

For this all you can do is vary the concentration of plant extract you are using for synthesis.

For ex, if you are preparing 100 mL of gold nanoparticles,

in a first batch you add for example 1 mL of plant extract,

make another batch where you add 1.5 mL of plant extract.

now as you vary the concentration of plant extract, concentration of L-Dopa will also vary.

but in all the batches you prepare, you have to keep concentration of Au and other materials (Whatever being used) and total volume of the AuNPs constant.

i think this will lead you to the exact concentration L-Dopa, your gold nanoparticles requires.

Dear Gaurav

L-DOPA content was found to vary within single leaf, or single cluster, even various seeds of a plant.

yes that is very obvious,

that why we should focus on the concentration of L-Dopa used for the synthesis of AuNPs. and that's why i suggest couple of batches to prepare that can give you the exact idea of concentration of L-Dopa require to AuNPs.

Method to observe concentration used of L-Dopa for AuNPs, i have mentioned in the previous answer.

i hope this would help.

Thanks a Ton Gaurav Vyas...I think u just solved my problem...

Hey,

Good to hear that.

you are welcome.

Best of luck.