Plate coating, in the Life Sciences environment, relates to microplates, mostly 96-well, most usually as full-plate or 8-well strip plates. Coating means the immobilization of antigen, antibodies or any other compound on the well surface, for the purpose of a binding assay. The „coated plate“ is part of a commercial ELISA kit, or of a home-brew (self-made) ELISA assay. Thus, the term ELISA coating is often used instead.
ELISA coating is typically applied to many plates at a time and is normally a production process. Therefore, automation is highly desired.
There are some variations in plate coating protocols, but they typically involve the following steps:
- Add coating solution (e.g. antibody or antigen)
- Overnight incubation, normally at room temperature
- Aspirate (suck-off coating solution)
- Wash 3x with washing buffer (step not mandatory for all coatings)
- Dispense blocking solution
- Incubate, typically 1-3 hrs
- Aspirate (suck-off blocking solution). Residual volume is critical in this step!
Plate coating is a demanding process. Most demands come from the fact that it is a production process, thus involving the preparation of many plates per day. The most important demands are:
- Throughput: it can go from a few dozens of plates per day in the case of home-made ELISA assays, up to hundreds, or even thousands of plates per day in the case of kit manufacturers. Reaching this throughput requires a very fast microplate washer.
- Reliable handling of troublesome ingredients: the reagents used in plate coating can be troublesome, as they may clog the thin needles typically found in microplate washers (for example, buffers containing high salt or sugar concentrations) or produce large amounts of foam (for example, detergent-containing wash buffers or protein solutions).
- Low residual volume: this is of utmost importance when removing the blocking reagent, as any remains would interfere in the assay to be performed in the plates, but also in the washing steps.
- Easy setup: time is gold when processing large amounts of plates, so it is important to be able to start the daily work as soon as possible.
- Easy maintenance: similarly, it is important to keep low the time and money to be spent in maintenance, and to avoid long downtimes in case of failure.
The Zoom HT Microplate Coating System satisfies all plate coating demands:
- High throughput thanks to its integrated stackers and single-rail design: it can coat or block up to 250 plates/hour, and wash (3x) up to 150 plates/hour.
- Clogging is prevented thanks to the large diameter of its dispense and aspirate needles and automated rinse and clean-out routines.
- Foaming is prevented thanks to the ability to optimize dispense position and speed, and the possibility to continuously add an anti-foaming reagent the the liquid waste trap.
- Lowest residual volumes thanks to 3D-positioning of the aspiration needles and its powerful vacuum system with a constant and stable flow rate.
- Daily setup and shutdown normally involve only running the integrated rinse and cleaning routines; waste management is extremely simplified thanks to its self-emptying waste trap, with automated addition of sterilization reagent, if necessary.
If you are looking for an instrument for plate coating, use the form below to contact us and one of our product specialists will contact you to study your specific needs.