Ratio-preserving super-resolution FLIM for quantitative live-cell lifetime imaging

SIM-fdFLIM achieves ~100 nm spatial resolution for quantitative frequency-domain FLIM in live cells, enabling 2.8 Hz imaging over a 56 x 56 {micro}m2 field while preserving lifetime fidelity.

• Why it matters: Photon-limited SR acquisition and reconstruction can distort lifetime estimates, especially for ratio-derived frequency-domain measurements, due to misregistration and noise amplification.
• What they did: The method combines DC-stabilized lifetime estimation with ratio-domain integrated variational estimation (RIVE) to correct channel misregistration and suppress noise amplification after SR reconstruction.
• The result: Across fluorophore standards, RIVE reduces lifetime standard deviation by approximately threefold versus non-RIVE SIM-fdFLIM while preserving mean lifetime agreement with calibrated widefield fdFLIM, and resolves cristae-scale heterogeneity and organelle-contact signatures in living cells.