The problem
Temperature is a crucial, yet often overlooked condition that affects the growth efficiency of mammalian and bacterial cell cultures. To achieve maximal growth rate, the temperature of the culture media needs to be maintained at the optimal level throughout the experiment.
While during a culture the media are maintained at the optimal for the organism level, their composition often dictates that they are stored at a lower (~2-8 °C) temperature. A typical culture medium for mammalian cells is composed of a complement of amino acids, vitamins, inorganic salts, glucose, and serum as a source of growth factors, hormones, and attachment factors; in addition to nutrients, the medium also helps maintain pH and osmolality. Many of these components are not stable for extended periods of time at elevated temperatures.
Sustaining mammalian cell cultures requires regular changes of the medium and/or subcultures (passages) into fresh culture medium. In many cases, the survival of the cells during these processes depends on the thorough pre-conditioning of the media at the desired temperature. Oftentimes, this means pre-incubating the media in a water bath for more than an hour, before they are ready to use.
This can impose time restrictions when experiments need to run at different time-points or need to be carried out early in the day or during out-of-hours, as access can be limited at these periods. Time optimization is needed.
The Idea
Our project was focusing on developing a remotely-controlled heated compartment, which can be kept in a cold environment.
Schematic of a remotely-controlled heated compartment prototype
The device can be used in laboratories to control specific working temperature (37 °C) of cell culture medium or reagents, shortly before use.
Specifically, the heating device finds application in the laboratories where microbiological or cell culture work are carried out.
The function of incubator is to maintain optimal temperature, humidity and other conditions such as the CO (CO2) and oxygen content of the atmosphere inside. Incubators are essential for a lot of experimental work in cell biology, microbiology and molecular biology and are used to culture both bacterial as well as eukaryotic cells.
With our mini-incubator we aimed to achieve the proper functionality of an incubator, but with the time optimization improvement due to the remote controls of temperature.
In May 2019, we had the great opportunity to take part in the OpenPlant Biomaker Challenge to develop our first prototype. For the first challenge we built an insulator polyester box mimicking the incubator and remotely controllable by the Telegram interface. This represented our proof of concept.
We then developed a set of scripts to locally control the electronic components, designing each command to work with a file-lock system that avoids collision when multiple users operate the device. The scripts allow to start the heating cycle, to report the current status of the device (temperature, humidity, heating status). To allow remote control of the device, a Telegram bot has been developed. The bot has a simple authentication system to allow only white-listed users to operate the device, a queue system allows to schedule multiple heating cycles, and the queue can be queried, and new tasks can be added, through the bot.
Following a series of successful tests our next task was to down-scale the device. We developed a customized 3D printed structure that allows us to efficiently organize the electrical components. In addition, 3D designed incubators can be customized to accommodate a range of different vessels and types of samples.
We also decided to organize a workshop for scientists at the Norwich Research Park. The main aim was to let the participants familiarizing with the programming in RasbperryPi, stressing that behind any problem there is a solution that can be achieved with a multidisciplinary approach.
What’s next?
We think that Biomaker Challenge was a great experience and a big opportunity for develop our idea. Now that we are able to obtain a proof of concept, we are aiming to further optimize our device and hopefully make it available as lab equipment to be used by researchers.
Blog written by IoHeat Team.