A limited number of approaches currently exist for 3D imaging and microscopy in biological research, medicine and industrial applications. Two-photon microscopy is both expensive and slow, owing to the need to scan a laser beam to every 3D location within a volume. Light-sheet technologies achieve optical sectioning through selective illumination, but are typically configured with two tightly aligned orthogonal objectives and a requirement to physically move a mounted sample. This limits both volumetric imaging speed and sample diversity (by shape, mounting ability, motion and scattering properties). Capturing volumetric imaging data from unmounted, living, and/or freely moving samples at faster-than-video rates is a major goal in neuroscience and biomedical research, and could find applications in medicine and a range of industrial processes. If available in a low-cost, simple-to-use benchtop platform, such a system could find a home in almost any biomedical research laboratory.
Swept Confocally Aligned Planar Excitation microscopy (SCAPE) allows for the rapid 3D imaging of fluorescent (or other) samples without the need for sample mounting and translation, and can image in both intact scattering and non-scattering samples to within scattering limits. SOLiS utilizes a unique optical design that permits a stationary camera to acquire de-scanned images of a moving light sheet plane as it is scanned through the sample at an oblique angle. Samples require no preparation and can be positioned as in a normal epifluorescence microscope. Limited only by camera speed and signal to noise, SOLiS can acquire high-density volumetric, polychromatic images at between 20 and 400 volumes per second with commercially available hardware. Image formation does not require a reconstruction algorithm (although spatial corrections for spatial scaling and deconvolution can be applied if desired). The system's region of interest is scalable, permitting imaging ranging from diffraction-limited microscopy to large-scale imaging of non-scattering structures and 3D profilometry. The technique does not require (but could incorporate) non-linear excitation, and is thus compact and inexpensive. Preliminary SOLiS 4D image sequences of crawling transgenic drosophila larvae and in-vivo rodent brain (blood flow and GCaMP6 calcium activity in superficial dendrites) have been acquired at over 20 volumes per second using an inexpensive prototype dual-color SOLiS system.
Publication: Nature article