Mirror-enhanced scanning light-field microscopy for long-term high-speed 3D imaging with isotropic resolution.

Various biological behaviors can only be observed in 3D at high speed over the long term with low phototoxicity. Light-field microscopy (LFM) provides an elegant compact solution to record 3D information in a tomographic manner simultaneously, which can facilitate high photon efficiency. However, LFM still suffers from the missing-cone problem, leading to degraded axial resolution and ringing effects after deconvolution. Here, we propose a mirror-enhanced scanning LFM (MiSLFM) to achieve long-term high-speed 3D imaging at super-resolved axial resolution with a single objective, by fully exploiting the extended depth of field of LFM with a tilted mirror placed below samples. To establish the unique capabilities of MiSLFM, we performed extensive experiments, we observed various organelle interactions and intercellular interactions in different types of photosensitive cells under extremely low light conditions. Moreover, we demonstrated that superior axial resolution facilitates more robust blood cell tracking in zebrafish larvae at high speed.