Environmental Control Module

Environmental control is crucial in microscopy to maintain optimal imaging conditions and ensure accurate results. Fluctuations in temperature, humidity, and gas can introduce artifacts, affecting sample integrity and resolution. Temperature stability prevents thermal drift and maintains focus and alignment. Controlled humidity preserves biological specimens' morphology and prevents shrinkage or swelling.

Environmental stability is vital for live-cell imaging, where even minor changes can affect cellular dynamics, metabolism, and development. Therefore, precise environmental control safeguards sample integrity and maximizes the microscope's performance, enabling researchers to obtain reliable data and draw accurate conclusions in various scientific fields, including biology, materials science, and nanotechnology.

The environmental control module allows tight control of environmental factors for long-term and live imaging. It is optimized for regulating:

1. Temperature — An adjustable Peltier-based water-cooling system enables precise regulation of conditions between 20° and 39° C. This creates optimal incubation conditions for various biological specimens, from marine animals to mouse embryos and organoids.
2. Gas concentration — The gas concentration for different components can be set from 0% to 15% for CO₂, 1% to 21% for O₂, and 20% to 99% for H₂O (humidity).

The Environmental Control Module comes with:

• Heated tubing to avoid condensation;
• High stability due to high-frequency measurements in a feedback loop; and
• Tight humidity control to avoid evaporation, which could change the media concentrations.

▲ Achieve precise environmental control by regulating both gas concentrations and temperature.

Tight temperature control and low phototoxicity of Bruker's selective-plane illumination microscopes (SPIMs) allow unbiased timelapse imaging of organoids. By studying these timelapses, scientists learn about morphogenesis, biophysics, and cell-to-cell interaction. 

Accurate temperature control ensures both sample viability and comparable development between samples, as metabolism and developmental speed are temperature dependent. Establishing a stable temperature reduces sample variability, as colder temperatures delay development, while higher temperatures increase the developmental speed.

Characterization and imaging of stochastic tumorigenesis in mammary organoids. Imaged on the InVi SPIM.  

Courtesy of A. Alladin, L. Chaible, L. Garcia del Valle, S. Reither Sabine, M. Loeschinger, M. Wachsmuth, J.K. Hériché, C. Tischer, M, Jechlinger. Tracking cells in epithelial acini by light-sheet microscopy reveals proximity effects in breast cancer initiation. eLife 2020;9:e54066 doi: 10.7554/eLife.54066

Controlling oxygen, carbon dioxide, and humidity is critical to maintaining stable sample conditions. Additionally, alterations of these levels can be used for dedicated experiments, such as studying the impact of low oxygen, called hypoxia. 

Acute hypoxia in mice can be used to understand hypoxia-induced cognitive decline, while longer exposures in zebrafish can help to understand the impact of hypoxia on development. These studies help to understand the effect of hypoxia on vascularization, tumorigenesis, the immune system, and other vital physiological processes.

▲ Stitched from 5 stacks in Imaris, each 340 slices, 16 hour/10 min. Courtesy of Prof. Liu Jingxia, Huazhong Agricultural University, China.