The immunoassay landscape has, however, dramatically changed in recent years with the development of reduced assay steps protocols, no wash ELISAs and new automated systems designed to run ELISA.
More recently, bead-based methods and microfluidic platforms have started to impact immunoassays and by coupling with single molecule detection look set to take the sensitivity of traditional ELISA to new levels.
The next most used format was 96-well strips with 39% of respondents using.
This was distantly followed by 5% using 384-well regular volume plates, and only 3% using either 96-well microfluidic channel plates or 384-well low volume plates (Figure 6).
The majority (57%) of survey respondents do not see the need for commercially available ELISA kits to be miniaturised, indicating that the standard volume 96-well format meets their current needs.
Of those seeking miniaturisation, a standard volume 384-well format (14% wanting) or a microchannel 96-well format (eg Siloam Biosciences Optimiser plates) were preferred (12% wanting) (Figure 7).Enzyme-linked immunosorbent assays (ELISA) have been around as one of the primary methods of analyte detection for more than four decades.Over the years many changes to the basic format have resulted in assay improvements, but some of the most recent look set to take the traditional ELISA to new levels.ELISA has gained widespread acceptance across a very diverse range of fields (eg diagnosis of infectious diseases, food allergen detection, plant pathogens to biomarkers), but it never achieved significant adoption by early drug discovery labs.This initially reflected the fact that plate washing was perceived to be difficult to automate, and subsequently the industry’s preference for homogenous screening methods, that could be miniaturised.Increasing sensitivity was ranked as the biggest issue (problem) with ELISA assays today.This was followed by reduced sample/reagent consumption and then improving precision by eliminating wash steps and increasing throughput.Most respondents (33% each) have either not applied any automation to their ELISA assays today (2012), or ELISA automation has been limited to plate washing only.Of the remainder, 13% have partially automated ELISA (ie sample/reagent additions, plate washing and incubation cycles); 12% have applied fully automated robotic processing to non-homogeneous ELISA (ie sample/reagent additions, plate washing, incubation and detection); 1% have partially automated ELISA by a homogeneous method (ie sample/reagent additions and incubation) and so far no respondents have applied fully automated robotic processing (ie including detection) to homogeneous ELISA (Figure 4).The main (primary) application area for survey respondents’ ELISA assays was immunology (17% selecting).This was followed by cancer (12% selecting); infectious diseases (11% selecting) and then inflammation (9% selecting).