Our nickel chelate products have NTA (nitilotriacetic acid) in the nickel form covalently attached to the surface. Ni NTA has been shown to preferentially bind histidine tagged molecules. It creates a very strong bond with molecules such as proteins and peptides when they have a 6-his tail. Binding also occurs with 5-his tags but it is not as strong a bond. If you are expressing the protein it is feasible to add the expression vector for the 6-his tag and the protein will be tagged. It is also easy to add histidines at the end if you are synthesizing peptides.
We can also supply products with other metal ions such as cobalt, copper, zinc and iron. These types have found use in many different assays.
Plates and strip plates
Nickel Chelate plates and strip plates are standard 96 well format. The have NTA (nitrilotriacetic acid) covalently attached to the surface using a proprietary binding procedure. The plates are extremely uniform well to well, plate to plate and lot to lot.
The bond between the NiNTA and the his-tagged molecule can be reversed by eluting with imidazole at moderate to high concentration. While this can be used as a way to collect small amounts of purified material, the binding capacity is about 250 ng/sq. cm. Since the internal surface of a well is about 2 square centimeters, the maximum that can be collected is only 0.5 ug.
The plates are available in clear versions for colorimetric assays and in opaque white for chemiluminescent assays and opaque black for fluorescent assays. They are also available in strip plate format which consists of 12 strips of 8 wells held in a frame in the standard 8 x 12 array. While the strip plates are more expensive than solid plates, they allow you to use as few or as many wells as you choose, eliminating the possibility of contamination of the unsed wells from spillage.