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Indium chemistry

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AdeebR

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Post Fri Mar 21, 2014 12:23 am

Indium chemistry

Hi everyone,

Does anyone know if indium-115 can be chelated with maleimide DOTA to use as a barcoding dye? I'm wondering if the indium-DOTA complex is stable or if it may release free indium as happens with platinum/palladium.

Also, does anyone know if indium can be used with the X8 or DN3 polymers to couple it to antibodies using the MaxPar kits?
Adeeb Rahman
Icahn School of Medicine at Mount Sinai, NYC
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mleipold

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Location: Stanford HIMC, CA, USA

Post Fri Mar 21, 2014 3:22 pm

Re: Indium chemistry

Hi Adeeb,

Yes, Indium can be used with both maleimide-DOTA, and the MAXPAR polymers (which have a DTPA chelator). I believe the Bodenmiller et al barcoding paper used In-DOTA, and several people at Stanford are still using the maleimide-DOTA as a live-dead, when loaded with natural-abundance Indium.

CD57 is a great choice for a marker to label with Indium.


Mike
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AdeebR

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Location: NYC

Post Wed Apr 02, 2014 6:30 pm

Re: Indium chemistry

Thanks Mike.

When doing Indium conjugations (or I guess any conjugations with non-DVS sourced isotopes), what buffer do you suspend the metals in to start with and at what concentration?
Adeeb Rahman
Icahn School of Medicine at Mount Sinai, NYC
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mleipold

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Post Wed Apr 02, 2014 10:56 pm

Re: Indium chemistry

HI Adeeb,

You generally want to keep the metals slightly acidic; this helps prevent the formation of insoluble oxides (at least with Lanthanides).

So, dissolving your salt powders in L buffer works. Alternatively, you can dissolve in MilliQ water and then spike in a small amount of 3% nitric: I think I've used 100uL 3% nitric/10mL MilliQ water. Hydrochloric works well too, but since you probably already have the Optima-grade ultrapure nitric on hand, you can certainly use that.
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afs1990

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Post Tue Oct 06, 2015 6:45 pm

Re: Indium chemistry

Is there any good source for isotopically pure Indium?

It seems like in in these articles, they used 113In (minor natural isotope).

http://www.pnas.org/content/suppl/2013/ ... l/sapp.pdf (Ly6G)

and

http://cancerdiscovery.aacrjournals.org/content/5/9/988 (CD3)
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mleipold

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Location: Stanford HIMC, CA, USA

Post Tue Oct 06, 2015 8:29 pm

Re: Indium chemistry

Various labs at Stanford have purchased highly-enriched In115 and highly enriched In113 from Trace Sciences.

You may also be able to get it from other sources such as Cambridge Isotopes Laboratory, but I haven't tried.
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MCOlivier

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Location: European Genomic Institute for Diabetes, Universitity of Lille, Institut Pasteur de Lille, France

Post Fri Oct 09, 2015 6:53 am

Re: Indium chemistry

I rebound on Adeeb's post to ask if some of you have an idea on the concentration of 115-Indium to use for conjugation with either MaxPar polymers (the X8 being the best for Fluidigm to load Indium) or with maleimide-DOTA ? (to an other extent, would you use the same concentration for 139-La ?)
Thank you all !
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AdeebR

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Location: NYC

Post Fri Oct 09, 2015 1:59 pm

Re: Indium chemistry

I've been initially dissolving the InCl3 salt to a 1M stock solution in diH20 and then diluting this to 50mM aliquots in L buffer.

I believe this the same concentration as the other metals in the MaxPar kits, which is convenient since the solution can then just be used according to the conjugation protocol (5uL to metal to 95uL polymer in L buffer).

And to echo Mike's earlier post, I've previously purchased In113 from Trace Sciences (@ 93% purity). For In115 I haven't really found it necessary to purchase the isotpically enriched version (99+%) since the naturally abundance of this isotope is already ~96%, and I typically only use these channels for highly expressed and easily resolvable markers.

Adeeb
Adeeb Rahman
Icahn School of Medicine at Mount Sinai, NYC
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mleipold

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Joined: Fri Nov 01, 2013 5:30 pm

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Post Fri Oct 09, 2015 3:01 pm

Re: Indium chemistry

To the best of my knowledge, Fluidigm MAXPAR salts are supplied at 50mM.

One thing to keep in mind when you're making maleimide-DOTA (or any other small molecule chelate, such as the SCN-Bz-EDTA used with Pd in Zunder et al and Mei et al): in most cases, you're not purifying it afterward. In other words, you make a stock solution of the mDOTA or SCN-Bz-EDTA, then add in whichever metal salt, and then either lyophilize or use without any subsequent HPLC purification or anything.

As such, unlike loading the MAXPAR polymer for antibody conjugation, you don't have washing steps to get rid of excess metal ions. Therefore, you typically want to use a slight excess of the chelator *over* the metal ion concentration: this way, at least in theory, *all* of the metal gets taken up and therefore there is no free metal to streak or leach in your samples.

This is often a 2:1 chelator:metal molar ratio (0.5x metal), but you could probably go up to 1:0.8 chelator:metal ratio (0.8x metal) without an issue. I don't think I'd go further, just to be absolutely sure I avoided pipetting/dissolving errors, but that's up to you.


Mike
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nkhanbham

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Post Wed Mar 07, 2018 8:18 pm

Re: Indium chemistry

I have just purchased some Indium (III) chloride from Sigma. I will make a 1M stock and dilute aliquots down to 50mM (with L buffer) as recommended above. I have a few questions.
What sort of shelf life do the metals have? It looks like I will have a lot of metal left over even in a single aliquot. Has anyone used the same aliquot after a long period in storage and achieved good labelling? Has anyone identified a recommended tube type for metal storage, that has low metal background?
Thanks,
Naeem
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