1. Overview
The Zeiss Axiovert 200 is a flexible, research-grade inverted microscope designed for live-cell and fixed-sample imaging. Built on a stable inverted stand, the Axiovert 200 supports transmitted-light contrast (brightfield, phase contrast), fluorescence imaging, and a wide range of interchangeable objectives, condensers and accessories (environmental chamber, motorized stages, cameras). It is commonly used in cell biology, tissue culture labs and materials research where upright access to samples from above is required (e.g., cells in flasks, multiwell plates, or Petri dishes).
Capabilities
- Inverted fluorescence microscope equipped with a high-intensity Xenon light source
- Observation of fluorescence signals
Features
2. Principle
- Inverted geometry: The objective lens sits beneath the stage while the specimen is placed on a horizontal stage above — ideal for imaging samples in liquid or culture vessels.
- Transmitted-light contrast methods: Brightfield, phase contrast and differential interference contrast (DIC) enhance contrast for transparent specimens by converting phase shifts to intensity differences.
- Epifluorescence: Excitation light is directed through the objective onto the sample; emitted fluorescence returns through the same objective, is separated by dichroic mirrors and filters, and detected by a camera or eyepiece. Filter cubes allow multi-wavelength imaging of different fluorophores.
- Optical path & illumination: Köhler or critical illumination (depending on configuration) provides even illumination. High-quality optics and correct alignment reduce aberrations and maximize resolution and signal-to-noise.
- Optional modules: Motorized stages, filter wheels, incubation/temperature control, and focus-drive modules enable time-lapse, multi-position and live-cell experiments.
3. Data interpretation
- Image contrast & modality: Choose the appropriate contrast mode—phase/DIC for unlabeled, low-contrast cells; fluorescence for labeled structures. Understand that each modality emphasizes different sample features.
- Resolution & sampling: Image resolution is governed by objective NA and wavelength. Ensure camera pixel size and acquisition settings satisfy Nyquist sampling to avoid under sampling or oversampling artifacts.
- Quantitative fluorescence: Intensity is affected by illumination power, exposure time, objective transmission and filter set. For quantitative comparisons use consistent settings, include controls, and correct for background and photobleaching.
- Artifacts to watch for: Photobleaching and phototoxicity during live imaging — minimize excitation and exposure. Out-of-focus light in thick samples — consider deconvolution or confocal alternatives. Halo/phase ring artifacts with phase contrast if illumination or alignment is off. Autofluorescence from media or plastics — use appropriate controls and spectral filters.
- Image quality checks: Verify focus stability, even illumination, absence of dust in the optical path, and correct flat fielding for quantitative workflows. Calibrate spatial scale using stage micrometer and record objective magnification/NA in metadata.
4. Example applications
- Live-cell time-lapse: Longitudinal monitoring of cell migration, division, morphology changes, or reporter expression with environmental control (37 °C, CO₂).
- Fluorescence imaging: Localization and co-localization studies using GFP/RFP/other fluorophores; simple single-plane fluorescence assays.
- Cell culture inspection and documentation: Rapid quality checks of confluent cultures, contamination screening, and transfection efficiency checks in flasks or multiwell plates.
- Phase/DIC imaging: Visualizing subcellular structures and thin specimens without staining (e.g., organelles, cell boundaries).
- Assay readouts: Imaging of wound-healing assays, cell viability stains, and phenotypic screening in multiwell formats (with motorized stage).
- Materials & suspension samples: Observing particles, droplets or fibers in liquid media where inverted geometry facilitates handling.