Parallelized volumetric fluorescence microscopy with a reconfigurable coded incoherent light-sheet array

Microscopy: parallel light sheets give a gentler view A new imaging technique called coded light-sheet array microscopy (CLAM) brings an improved ability to visualize biological samples in three dimensions while minimizing the damage. A research team, led by Kevin Tsia at the University of Hong Kong, developed the technique and demonstrated its use on a variety of biological imaging scenarios. CLAM is a new form of 3D fluorescence microscopy, which collects all the fluorescence signals from the entire illuminated volume of a sample in parallel. Its key innovation is the way it uses a concept called infinity mirror to generate an array of parallel slices of laser light (light sheets) for three-dimensional imaging without the need for repetitive scanning and with much gentler illumination than the state-of-the-art techniques. CLAM could be applied to existing light sheet fluorescence microscopes, with minimal system modifications. Parallelized fluorescence imaging has been a long-standing pursuit that can address the unmet need for a comprehensive three-dimensional (3D) visualization of dynamical biological processes with minimal photodamage. However, the available approaches are limited to incomplete parallelization in only two dimensions or sparse sampling in three dimensions. We hereby develop a novel fluorescence imaging approach, called coded light-sheet array microscopy (CLAM), which allows complete parallelized 3D imaging without mechanical scanning. Harnessing the concept of an infinity mirror, CLAM generates a light-sheet array with controllable sheet density and degree of coherence. Thus, CLAM circumvents the common complications of multiple coherent light-sheet generation in terms of dedicated wavefront engineering and mechanical dithering/scanning. Moreover, the encoding of multiplexed optical sections in CLAM allows the synchronous capture of all sectioned images within the imaged volume. We demonstrate the utility of CLAM in different imaging scenarios, including a light-scattering medium, an optically cleared tissue, and microparticles in fluidic flow. CLAM can maximize the signal-to-noise ratio and the spatial duty cycle, and also provides a further reduction in photobleaching compared to the major scanning-based 3D imaging systems. The flexible implementation of CLAM regarding both hardware and software ensures compatibility with any light-sheet imaging modality and could thus be instrumental in a multitude of areas in biological research.