What is an ELISA plate?
A microplate whose surface is the product: treated polystyrene wells that adsorb protein evenly, in plain language.
An ELISA plate is a microplate, almost always 96 well polystyrene, whose wells are treated so protein adsorbs to them evenly and stays through washing. ELISA (enzyme-linked immunosorbent assay) works by building the assay on that surface: a capture antibody or antigen coats the well, the sample binds to it, and an enzyme-linked detection step produces a color the reader measures. A regular assay plate is a container; an ELISA plate is a reagent.
The general microplate concept is covered on the 96 well plate guide; this page defines the ELISA member of the family.
What the plate does in the assay
Four jobs, all surface jobs. Coating: capture protein passively adsorbs to the treated wells in a uniform layer. Blocking: the remaining surface is covered so later reagents cannot stick nonspecifically. Binding: the analyte in the sample, then the detection antibody, attach in sequence to what the surface holds. Reading: the enzyme substrate develops color in proportion to bound analyte, read by absorbance, commonly at 450 nm for TMB. Every step depends on the coating being even, which is why the surface treatment, not the molding, is what an ELISA plate is bought for.
How it differs from a regular assay plate
Physically, barely: same footprint, same 96 wells, same polystyrene. The differences are the treatment and the promise. An ELISA plate is surface treated for protein adsorption and sold in binding grades, with the binding behavior specified and lot-controlled for immunoassay use. A general assay plate makes no binding promise; protein coats it weakly and unevenly, and an ELISA built on one gives drifting, irreproducible numbers. The removable-strip variant, frames holding 8 or 12 well strips, exists only in this family, because ELISA runs are often smaller than a full plate.
The choices inside ELISA plates
Binding grade: medium bind for larger, more hydrophobic proteins and many antibodies; high bind for smaller or more hydrophilic molecules that need a more adsorptive surface. Solid or strips: full plates for full runs, strips so a partial plate is not wasted. Color: clear for the standard colorimetric read; black and white versions exist for fluorescence and luminescence based immunoassays. Pre-coated or coat your own: streptavidin and capture-antibody pre-coated plates trade money for time and uniformity. The coating guide works through the binding decisions in full.
Related guides
Common questions
What is an ELISA plate made of?
Polystyrene, the standard assay plastic, with a surface treatment that makes the wells adsorb protein. The treatment is the defining feature; untreated polystyrene binds protein weakly and unevenly.
Can I use a regular 96 well plate for ELISA?
It will physically hold the liquids, and that is where the good news ends. Without a binding-grade surface, coating is weak and uneven, and the assay drifts. Use a plate sold in a binding grade for ELISA; it is the cheapest variable in the assay to get right.
Why are ELISA plates 96 well?
The 96 format is the reader and washer standard the method grew up on, and a plate holds a standard curve, controls, and dozens of samples in one run. 384 well ELISA plates exist for miniaturized work, with volumes scaled down.
What does high bind mean on an ELISA plate?
The surface is treated to adsorb more protein, and to hold smaller or more hydrophilic molecules that medium bind surfaces hold poorly. High bind is not automatically better: for large hydrophobic proteins, medium bind coats as well and can give lower background. The coating guide matches grade to molecule.