Design and implementation of a climate chamber for moisture sensitive nanotomography of biological samples.

Abstract

Deep understanding of the structural composition and growth of biological specimens is becoming increasingly important for the development of bio-based and sustainable material systems. Full-field nano-computed tomography is particularly suitable for this purpose as it allows for non-destructive 3D imaging at high spatial resolution. However, most biological samples are functionalized by water and respond sensitively to any changes in climate conditions, specifically relative humidity, by adjusting their material moisture content. To date, only a limited number of tomography instruments offer an in situ climate control option to users. These, however, are limited either by the range of relative humidity states, the long times required to change the climate state, or obstruction or attenuation of the beam. Here, the first fully automatized climate cell for in situ full-field nanotomography is presented. It has been designed, built and integrated at the nanotomography station at the P05 imaging beamline, operated by Hereon at the DESY storage ring PETRA III, Germany. The highly flexible and windowless design allows the humidity dependent swelling and shrinking of lignified plant cell walls to be studied in situ, using phase contrast nanotomography. The concept of this climate chamber can easily be integrated into other setups. It operates in the relative humidity range of 0-90% and can be controlled in a temperature range of 10-50°C. Climate conditions can be adjusted at any time, remotely from the control hutch by using a humidity generator. Results show that the developed setup maintains a stable climate during the entire duration of a tomographic scan at different humidities and does not obstruct the sample or hinder the imaging conditions. During the tomographic investigation the sample remains stable in the flow of the air stream and shows typical cell wall swelling and shrinking behaviour depending on the equilibrium moisture content. This new climate cell is now available to all users of the P05 nanotomography instrument for conditioning samples, serving a wide range of scientific applications.

Plant phenotyping relevance

植物細胞壁の膨潤・収縮を非破壊に取得するナノトモグラフィー用の自動環境制御セルを開発・統合し、安定性と撮像性能を検証しているため、植物表現型取得法が中心である。

Code and data availability

The article describes a climate chamber for in situ nanotomography of wood cell walls and an image analysis workflow (Amira-AVIZO affine registration, HoloTomoToolbox, TomoPy), but no blocks contain a data availability statement, deposited phenotype datasets, sample images, or author analysis code with a public URL. C-

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