A Microplate Reader, circa 1981

Courtesy of Biotek Instruments Inc.

In the late 1970s, researchers who wanted to quantify the results of new immunoprecipitation assays, such as ELISA, had three choices: risk human error and a headache by using a manual reader, break out the cuvets and the spectrophotometer, or pay as much as $15,000 for a bulky automated reader.

In 1981, Winooski, Vt.-based, BioTek Instruments, introduced the EL307. Roughly the size of a toaster oven, the EL307 combined the ease of automated microplate reading with the low cost of the manual readers. Users still had to reposition their 96-well microplates by hand, but a spring-loaded device and magnets made this process easier than with purely manual readers. The EL307, shown here in a BioTek pamphlet from 1984—1985, was also directly connected to a printer that simultaneously recorded results from each well, eliminating the need to manually record each well's location. It took a mere three minutes to produce results from a full microplate. "It was about as easy as you could get for pushing a plate around," says longtime BioTek applications specialist, Ted Quigley.

BioTek would sell about 450 units (at $3,900 a piece) over the next two years. Quigley says that initial orders came from immunology and infectious disease labs, but that the EL307 "very quickly spread to all life science disciplines from anatomy to zoology." This meant that more labs and more scientists could develop new tests such as fluorescence, luminescence, and protein assays common in research today.

In 1984, for example, a University of California, Riverside, team led by immunologist Carl Ware used the EL307 and a new colorimetric assay (instead of the slower and less precise radiological methods previously used) to determine the cytotoxicity of chemicals produced by human lymphocytes. Compared with older methods, Ware said, it took them about one-tenth of the time. Today, automated readers can give digitized results from myriad assays in as little as five seconds.