Process Impurity Measurements
Conventional microplate ELISAs are widely used to quantify impurities and contaminants in biopharmaceutical process development. ELISA uniquely combines the versatility, selectivity and sensitivity required for determining concentrations of specific impurities (such as leached protein A or insulin) or general host protein (HCP ELISA) to the ppm level in the presence of high product concentrations. However, processing ELISAs manually can take from 4 to 24 hours and results can vary greatly according the user expertise and technique. Increasing demands from Speed-to-Clinic and Quality-by-Design (QbD) initiatives have turned ELISAs into a major process development bottleneck.
Using AssayMAP ELISA cartridges as the solid phase instead of conventional microplates allows simple conversion of these manual assays into highly precise, automated ones that can use currently validated ELISA reagents. Samples and reagents are pumped at controlled flow rate through cartridges packed with non-porous polystyrene beads that have a binding surface area similar to the bottom of a microplate well. Beads offer a diffusion path on the order of tens of microns, significantly shorter than the several millimeters of a microplate, which allows improved mass transport and allows each reaction step to go to completion in just a few minutes.
An automated AssayMAP ELISA offers:
- Accelerated method development and troubleshooting using validated reagents
- Binding reactions that run to completion
- Reduced dependence on manual technique, timing, mixing and temperature variations
- Improved precision and sensitivity
- Enhanced reproducibility, with assay CV's typically well under 5%
- Freedom to walk away for the duration of the assay
Pumping substrate through the cartridge at a controlled flow rate reacts with bound enzyme to produce product that is collected in a microplate well and read in a standard plate reader. Assay sensitivity can be controlled by either reducing the flow rate to offer a longer enzyme/substrate reaction time and yield a stronger product signal for a given concentration or by increasing the flow rate to enable higher concentration samples to stay within range.
See the research data: