Evolution of the Laboratory Incubator
Tracing the origins of the laboratory incubator and looking ahead to future advances.
Incubators are used in modern research laboratories to maintain a stable environment for processes such as growing cells and microbiological cultures and incubating antibodies and cells for fluorescence microscopy.
The simplest incubators are little more than temperature-controlled ovens, capable of reaching temperatures of 60 to 65 °C, but usually used at about 36 to 37 °C. However, most modern incubators are also able to generate refrigerated temperatures, and control humidity and CO2 levels. Many incubators also offer features such as automatic shaking, measured by revolutions per minute.
Laboratory incubators were first properly introduced during the second half of the twentieth century, when doctors realized that they could be used to identify pathogens from the bodily fluids of patients. In this application, a sample is transferred to a Petri dish, placed on a rack inside the incubator and heated to body temperature (37 °C). The appropriate quantity of atmospheric CO2 or N2 necessary for cell growth is then supplied, encouraging the microorganism to multiply, enabling easier and more definite identification.
In the 1800s, researchers began searching for the ideal in vitro environment in which to maintain cell culture stocks.
The first CO2 incubator developed consisted of a simple bell jar containing a lit candle. Cultures were placed under the lid of the jar alongside the lit candle, before the jar was moved to a dry, heated oven. This system may be considered the first “air-jacketed” CO2 incubator.
During the late 1960s, the first dedicated, commercial CO2 incubators were developed. It was during this time that New Brunswick Scientific (NBS) introduced a range of incubator products including the Psychrotherm, the first refrigerated incubator shaker, the Model G25 large-capacity console-style incubator shaker, and the G76 water bath shaker. These models can still be found operating in labs around the world to this day.
In 1984, SHEL LAB introduced the innovative general purpose incubator, which proved extremely popular in the marketplace. This incubator offered a unique warm air-jacket design, heated outer door, and five strategically placed heating elements to deliver uncompromising temperature uniformity, with no hot spots.
During the late 1990s, Torrey Pines Scientific developed the first Peltier-based benchtop incubators capable of chilling and heating. These incubators were marketed under the trade name EchoTherm.
In 2001, a patent was granted for an ambient-temperature stabilization control system for laboratory incubators. This device was able to effectively maintain the incubator temperature within a desired range and to accurately control the rate of heat loss from the incubator as the ambient temperature rose.
In 2003, NBS began worldwide distribution of a new line of CO2 incubators featuring a direct-heat, fanless design. These incubators were lighter in weight than traditional water-jacketed designs, and featured the most advanced CO2 controllers ever developed, complete with on-board diagnostics, help menu and auto-baseline reset.
Also in 2003, a patent was issued for a high-efficiency microplate incubator. This incubator offered superior temperature uniformity and stability through a simple construction in which multiple incubation chambers were stacked to conserve laboratory space. The multiple incubation chambers could be electronically controlled by a single temperature control assembly in a master incubator. A water reservoir that could be filled externally was provided inside the chamber.
In 2006, NBS introduced two new CO2 incubators—the Innova CO-170 and Excella CO-170—which offered greater internal space without increasing external size. In the same year, NBS also introduced 14 new shakers, including four new bench and floor model shakers, two new space-saving stackable I-26 & I26R incubator shakers and the new Excella® line.
In 2008, CARON introduced the new largecapacity IR-CO2 incubator, the industry’s first and only large-capacity reach-in IR-CO2 incubator with an automatic moist heat decontamination cycle that cleansed the unit overnight. This incubator also offered a user-configurable interior that could support shakers and cell rollers and an optional environmentally friendly water recirculation system.
In 2009, SANYO released the industry’s first and fastest H2O2 sterilization method available—the Sterisonic™ GxP, MCO-19AIC (UVH) Cell Culture Incubator—described as the most complete cell culture solution for highly regulated applications or conventional incubation. This was considered to be the new standard of incubation technology. This incubator used the industry’s first rapid H2O2 sterilization system, an under three-hour decontamination process that is still the fastest method available.
In 2010, BINDER launched the BINDER gas supply kit which increased user convenience by automatically changing the supply source to a second gas bottle as soon as the first gas bottle is empty. This prevented the need for researchers to come into the laboratory at night or over the weekend to change the gas bottle. The set also had an acoustic and an optical alarm function as well as a potential-free alarm output for external reporting systems.
Future of lab incubators
Laboratory incubators have evolved steadily over the latter part of the twentieth century, and have remained an important piece of laboratory equipment. Experts believe that in the future the incubator market will derive most of its growth from the bio-technology industry. As our medical knowledge and technology improves, and researchers become increasingly exacting, it is believed that growth chamber-type incubators will be required that have an even greater sensitivity in the control of temperature and relative humidity.
Another probable area of growth for incubators is within the field of genetic engineering, in which scientists manipulate the genetic materials in explants, sometimes combining DNA from discrete sources to create new organisms. Although genetic engineering is a controversial subject for many, this technology has already delivered tangible benefits, including the manufacture of insulin and other biologically essential proteins. Genetic engineering has also been shown to improve the nutritional content of fruits and vegetables and to increase the resistance of certain crops to disease. Genetic engineering relies heavily on the use of well-controlled and adjustable incubation, and it is within the field of biotechnology that some experts believe lies the greatest potential of the incubator.