Interferometric Image Scanning Microscopy for label-free imaging at 120 nm lateral resolution inside live cells.

Area of Science:

• Life Sciences
• Microscopy
• Cell Biology

Background:

• Conventional fluorescence microscopy faces limitations like phototoxicity and labeling issues.
• Label-free techniques, such as interferometric scattering microscopy (iSCAT), detect nanoscale structures without dyes.
• Confocal iSCAT has enabled subcellular imaging in live cells with high contrast.

Purpose of the Study:

• Introduce interferometric image scanning microscopy (iISM) as a next-generation live-cell imaging technique.
• Achieve high-resolution, low-impact imaging of intracellular dynamics.
• Enable correlation of label-free structural information with molecular specificity.

Main Methods:

• Combined interferometric detection with image scanning microscopy.
• Achieved approximately 120 nm lateral resolution.
• Operated at tenfold lower illumination power per diffraction-limited spot compared to previous methods.

Main Results:

• Significantly reduced photodamage while enhancing signal-to-noise and contrast.
• Visualized intracellular organelles (endoplasmic reticulum, cytoskeleton, mitochondria, vesicles) in live cells.
• Enabled essentially unlimited observation times for live-cell imaging.

Conclusions:

• iISM provides a powerful new tool for high-resolution, low-impact live-cell imaging.
• Facilitates the study of dynamic biological processes under label-free, near-native conditions.
• Opens new avenues for biological insights into host-pathogen interactions, trafficking, and cytoskeletal dynamics.