Super-resolution radial fluctuations (SRRF): a versatile and accessible tool for live-cell nanoscopy

Area of Science:

• Biophysics
• Cell Biology
• Microscopy

Background:

• Traditional super-resolution microscopy methods like STED and SMLM face limitations in phototoxicity and hardware complexity.
• Achieving sub-diffraction resolution (50-100 nm) is crucial for visualizing dynamic subcellular processes.
• Standard wide-field microscopy is limited by the optical diffraction limit (200-300 nm lateral resolution).

Purpose of the Study:

• To introduce and detail the Super-resolution radial fluctuation (SRRF) microscopy technique.
• To highlight SRRF's advantages over existing super-resolution methods for live-cell imaging.
• To discuss the implementation, applications, and advancements of SRRF.

Main Methods:

• SRRF analyzes fluorescence intensity fluctuations in time-series images from standard wide-field microscopy.
• It calculates local gradient convergence (radiality) to reconstruct sub-diffraction structures.
• The open-source NanoJ-SRRF platform optimizes parameters for resolution enhancement and noise suppression.

Main Results:

• SRRF achieves lateral resolutions of approximately 50-100 nm, surpassing the diffraction limit.
• The method minimizes phototoxicity and hardware requirements compared to STED and SMLM.
• SRRF is compatible with conventional dyes and live-cell imaging, enabling visualization of dynamic processes.

Conclusions:

• SRRF provides a powerful, low-phototoxicity approach for high-resolution live-cell imaging.
• Advancements like eSRRF and VeSRRF are expanding SRRF's capabilities, including multicolor and real-time imaging.
• SRRF has broad applications in ultrastructural studies, cell biology, and potentially clinical pathology.