Automated Microbeam Observation Environment for Biological Analysis
The Automated Microbeam Observation Environment for Biological Analysis(AMOEBA) is a highly flexible modular environmental control system used to create incubator conditions on the microbeam endstation. Irradiation of cells using a microbeam require cells to be removed from an incubator which can cause physiological changes to cells because of the lower CO2 concentration, temperature and relative humidity outside of the incubator. Consequently, for experiments where cells require irradiation and observation for extended time periods, it is important to provide a controlled environment. The AMOEBA takes advantage of the recent “maker” movement to create an open source control system that can be easily configured by the user to fit their control needs. The AMOEBA can control cell medium temperature, CO2 concentration, and relative humidity to create a stable environment that allows cells to multiply while on the endstation over a period of 36 h. The system is low-cost (costing less than $2700 to build), and customizable to specific user needs.
The figure shows a side view schematic of the environmental chamber used in the AMOEBA system. The chamber was manufactured using 3D printing. The chamber fits the existing microbeam endstation and accommodates imaging and irradiation through established techniques. The chamber forms a controlled volume where the CO2, humidity, and temperature are monitored and controlled. The chamber has inputs for humid air and CO2 and the flow rates of the inputs are controlled using modules separate from the chamber.
While the chamber contains sensors, input ports, and creates a control volume, the control hardware pieces of AMOEBA system are separate units. The control system is set up with software run on a computer and uses a CAN bus to gather data and control modules containing microcontrollers. Each module, which is programmed with Arduino software, can be set up to control almost any sensor or actuator. CAT5 cables connect modules to power the system and a USB cable connects the system to a computer. A picture of the environmental chamber is shown below along with the entire system on the microbeam endstation.
Example Environmental Control
As a proof of concept for the utility of the AMOEBA system, it was configured to replicate incubator conditions, i.e. 37°C ±2°C, 5% ± 0.5% CO2 and 99% ± 1% relative humidity. The chamber was set up and continuously monitored for a 6 hour period. A graph of the values of the control parameters is shown below. Each of the parameters quickly settled and was maintained through the experiment. The disruptions every two hours were due to removing and replacing a dish within the system and control conditions returned to set points shortly after each event.
For a long-term test of the system, a dish of HeLa cells was placed within the system and monitored by taking images every 10 minutes for 36 hours. Cells demonstrated the ability to replicate while being observed which indicated the cells remained healthy throughout testing.
More information in our publication:
England, Matthew J., Alan W. Bigelow, Michael J. Merchant, Eirini Velliou, David Welch, David J. Brenner, and Karen J. Kirkby. "Automated microbeam observation environment for biological analysis—Custom portable environmental control applied to a vertical microbeam system." Sensors and Actuators B: Chemical 239 (2017): 1134-1143.