The Microscope Cage incubator, produced by H-Tech C. responds to the need of controlling the environmental conditions around a microscopy workstation to carry out prolonged observations on cell cultures or biological specimens, allowing, at the same time, enough space for other equipment. For instance, if a biological fluid has to be investigated under flow conditions, a flow cell, the tubes and the pumps can all be inserted into the cage incubator, ensuring temperature, humidity and CO2 control all around.
The whole system, tested up to four weeks, is heated through radiators communicating with a controlled water bath. The apparatus is made of lexan (Fig.1) and it ensures a thermal accuracy within 0.1°C. The desired gas stream of humid air and CO2 is fed into a small incubating chamber containing the specimen, avoiding in this way condensation on the cage walls and the formation of an all around humid ambient that could damage mechanical parts of the microscope and of the motors.
The entire cage incubator is water jacketed, and temperature control is achieved by means of a PID controller communicating with a water bath via serial port. The PID controller is provided along with the incubator. The high thermal inertia of this heating method ensures a thermal stability and accuracy that an electrical resister system cannot provide. The cage incubator ensures a temperature stability within 0.1°C.
We report the temperature profile measured with a thermocouple
directly inserted into a Petri dish placed on the microscope stage. The initial transient refers to the onset of flow into the water-jacket, starting from room temperature. To asses controller performance, during the measurement, ambient temperature was varied within the range 20-27°C. The desired temperature of 37°C is reached in about 2 hours. After the transient, temperature into the Petri dish remains constant within 0.1°C, despite changes of ambient temperature. To check temperature uniformity within the chamber, five thermocouples were inserted in different places of the incubator. The five readings were always within 0.2°C.
To control humidity and CO2 levels, avoiding condensation on the cage walls and damaging of the microscope mechanical parts, a little multi-vessel incubating chamber is provided along with the Microscope Cage Incubator. This little chamber fits right on the microscope stage, allowing in this way prolonged observations on your sample. The desired gas stream is provided by an air + 5% CO2 reservoir, pre-heated in a specially-designed flow pattern and humidified by a compact gurglement unit. The pre-heater guarantees that also the gas steam is at the desired temperature (e.g. 37°C) when fed to the incubating chamber, thus limiting temperature perturbations. On the other hand, the humidifying module and the incubating chamber allow to condition the environment only close to the sample, avoiding at the same time sample evaporation and harmful condensation on the Cage walls.
HOW TO ORDER A MICROSCOPE CAGE INCUBATOR