Among all the ligand bioassays developed, the one which has emerged victorious is the Enzyme Linked Immuno Assay, or ELISA.
Variations on the ELISA now have to power to discriminate antigens down to the femtomole/femtogramme (10-18 of a kilogramme) level, depending on how it’s implemented, offering researchers unprecedented levels of sensitivity.
Harnessing the power of antibodies to discriminate between different antigens, the ligand binding assay, in its many forms is one of the most powerful and common tools used in the biosciences to measure, well, almost anything.
The growth of ELISA’s
With that power, it’s no surprise that the market for ELISAs and their ilk has seen considerable growth over the decades since first being described in the early 70s. In fact, some market reports estimate that the total value of the ELISA and ELISA reagents market is likely to have a compound annual growth rate of 8.2%, reaching a value of US$25.45 billion by 2021.
ELISAs have improved drastically since the 70s. Thanks in part to improvements in the production process of their constituent antibodies, but also as technology developed in the form of the chemistries used to develop a signal and the technologies used to detect them. While TMB is perhaps the most common chromogenic detection system, chemifluorescent, chemiluminescent and electrochemilumiescent technologies have all been used to improve sensitivities even further.
Not only this, but a number of platforms have emerged offering the ability to perform ELISAs in multiplex, that is, analysing a single sample at a single time for multiple antigens of interest. For example, Luminex systems and BD Biosciences Cytokine Bead Arrays. Arguably, these aren’t ‘true’ ELISAs, but many antibody manufacturers will likely find their products being used by researchers creating their own custom multiplexes in just such a context.
However, many such systems (and especially the hardware needed for them) are proprietary, sometimes limiting their scope in laboratories. Meaning that the good ‘ol ‘tried and tested’ methods of detection, such as TMB and simple microwell plate reader are used in most bioscience labs.
Whilst proprietary systems have no doubt led to some degree of market fragmentation and service sometimes high value, but niche, markets, such as biomarker screening where multiplexing technologies are a very useful cost-effective approach, for manufacturers the development of ELISAs and their kind relies on first having access to a reliable and specific source of the raw reagents – the antibodies.
Indeed, producing an ELISA is a natural next step for many antibody manufacturers, since it requires little extra equipment once you’ve produced antibodies to whatever target. It does, however, require some degree of expertise to develop and produce reliable and robust ELISAs.
While simple in principle and in use, balancing the many different elements of an ELISA, such as capture and detection antibodies, concentrations, buffers, incubation temps and timings and so on, is actually a pretty involved process. Meaning that validating an ELISA for a specific sample type (serum, plasma, cell culture etc) can be a time-consuming affair. And, invariably, a customer will come along who wants to know if the ELISA will work with their rare, weirdly specific, sample type…
But with all that being said, ELISAs have a huge place in the biosciences market, and, if you have the expertise to develop and produce them in house (or at the very least offer a tested protocol for your antibodies) represent a clear way to help maximise value and sales from your efforts developing new antibodies.