Its difficult to understand what are you trying to do.  could you clarify?

Do you want to elute a protein from an ELISA plate? How was it captured?

Yes, these words don't fit together like that.  ELISA is not a way to elute his-tagged proteins, but is a protein detection method.  What your boss meant when they said them was probably, that you should:

(1) Elute your protein first (by any means such as, pH, imidazole or EDTA),

(2) Then test by ELISA whether you've got the right thing, how much of it, and how pure it is. 

One can't elute protein using ELISA. No ways. You can only check it's sensitivity and specificity.

In principle you can. But columns are used because of mostly their enormous surface area. I'm guessing you need 2 96-well plates to have an equal amount of protein purified from a 500ul mini column. Also because of the volume to surface area ratio, you would also have very, very diluted protein. And mate concentrating protein is always a pain in the a** and you almost certainly will suffer huge loss during the process, especially when its dilute.

But if you really feel like doing that, you would try to coat divalent cations (Mg2+ or Mn2+) on the bottom of your plate. This I have no clue is possible or not. Then you would proceed just like prepping protein from a column; incubate with your protein, wash, wash again, and elute with either a high [imidazole] or low pH buffer. The condition again will have to be tested empirically. Personally I would just get a plastic column and some resin and pack the column myself.

One may use Ni-NTA column s are used to purify the proteins.........then go for ELISA

Thank you all for your answers. I was trying to ask whether i can use an ELISA to isolate a His-Tagged protein from a protein mixture. I know an IMAC procedure can already do this and imidazole can be used to elute proteins from Nickel resin. And i have already known that ELISA can be used to identify His-Tagged proteins. My main aim is recapture functional His-Tagged proteins that attached to Histidine specific antibody, from the well and use it for my jobs.

You can do that, but the amount of protein you will recover from an ELISA well would be minimal, because as it was already explained the plastic surface in this case is smaller than the surface in a chromatographic column. Chromatographic matrices are designed for that use so are much better.

If you want to use an anti-His antibody, you dont need any ELISA, you can immobilize the antibody in a chromatographic matrix like sepharose, and perform an immunoaffinity chromatography, eluting with low pH.

On the other hand, there are many possibilities to optimize  IMAC. As your protein has a His tag, the easiest way to purify it could still be IMAC. Is there any reason to avoid it?

Gertrudis has provided very informative suggestions, you could either: A. immobilise your anti-His Ab to protein A/G sepharose beads before the pulldown, or B. still try to do another IMAC on the pulldown product. The conformation of an anti-His Ab to the His6-tag may not obscure the binding to NTA column per se. Or, to make things even more complicated, you could use another Ab that recognises the anti-His Ab to do another pulldown. Then a simple SDS PAGE would tell you how much protein and Ab you have in the prep.

In theory, you can use Ni2+ coated plates available from ThermoScientific (https://www.thermofisher.com/order/catalog/product/15142?ICID=search-product) to purify His-tagged proteins but the eluted protein would very small and diluted (as someone already pointed out above). However, these issues may not be problem for you since you are planning to re-capture the his-tagged protein using his-tag antibody.

Thank you all for your answers.