Keywords: phase contrast microscope, transparent sample, live cell imaging, phase difference

The phase contrast microscope converts the optical path difference of the sample into amplitude difference through a phase ring, allowing transparent samples (such as live cells) to be observed without staining. Its core principle is based on the interference effect of light and is widely used in cell biology and developmental biology.

1、 The core structure and principle of phase contrast microscope

The phase contrast microscope inserts a phase ring into the condenser and objective lens to convert the phase delay caused by the sample into contrast between light and dark. For example, when observing unstained cells, the nucleus appears as a shadow due to differences in refractive index, while the cytoplasm appears as a bright area.

2、 Live Cell Imaging: From Dynamic Processes to Drug Response

The phase contrast microscope can observe the morphological changes of living cells for a long time. For example, in cell migration studies, phase contrast imaging can track the formation and contraction of pseudopodia; In drug screening, phase contrast microscopy can monitor changes in cell morphology and evaluate drug toxicity.

3、 Combining with fluorescence microscopy: multimodal imaging

Contrast microscopy is often used in conjunction with fluorescence microscopy to achieve synchronous observation of structure and function. For example, in neuronal research, phase contrast imaging can display cell bodies and processes, while fluorescent labeling can locate specific proteins and reveal the mechanism of neural circuit construction.

4、 Technological Challenges and Future Trends

The current challenges include phototoxicity, background noise, and resolution limitations. Future development directions include:

Digital holographic microscope: Reconstructing sample phase information through interference fringes to enhance resolution.

Structured light illumination microscope: using periodic illumination mode to break through the diffraction limit.

Adaptive optics technology: compensates for aberrations and improves image quality.