A key challenge when imaging whole biomedical specimens is how to quickly obtain massive cellular information over a large field of view (FOV). We report a subvoxel light-sheet microscopy (SLSM) method enabling high-throughput volumetric imaging of mesoscale specimens at cellular resolution. A nonaxial, continuous scanning strategy is developed to rapidly acquire a stack of large-FOV images with three-dimensional (3-D) nanoscale shifts encoded. Then, by adopting a subvoxel-resolving procedure, the SLSM method models these low-resolution, cross-correlated images in the spatial domain and can iteratively recover a 3-D image with improved resolution throughout the sample. This technique can surpass the optical limit of a conventional light-sheet microscope by more than three times, with high acquisition speeds of gigavoxels per minute. By fast reconstruction of 3-D cultured cells, intact organs, and live embryos, SLSM method presents a convenient way to circumvent the trade-off between mapping large-scale tissue (>100 mm3) and observing single cell (∼1-μm resolution). It also eliminates the need of complicated mechanical stitching or modulated illumination, using a simple light-sheet setup and fast graphics processing unit-based computation to achieve high-throughput, high-resolution 3-D microscopy, which could be tailored for a wide range of biomedical applications in pathology, histology, neuroscience, etc.
There currently is a limited ability to interactively study developmental cardiac mechanics and physiology. We therefore combined light-sheet fluorescence microscopy (LSFM) with virtual reality (VR) to provide a hybrid platform for 3- dimensional (3-D) architecture and time-dependent cardiac contractile function characterization. By taking advantage of the rapid acquisition, high axial resolution, low phototoxicity, and high fidelity in 3-D and 4-D (3-D spatial + 1-D time or spectra), this VR-LSFM hybrid methodology enables interactive visualization and quantification otherwise not available by conventional methods such as routine optical microscopes. We hereby demonstrate multi-scale applicability of VR-LSFM to 1) interrogate skin fibroblasts interacting with a hyaluronic acid-based hydrogel, 2) navigate through the endocardial trabecular network during zebrafish development, and 3) localize gene therapy-mediated potassium channel expression in adult murine hearts. We further combined our batch intensity normalized segmentation (BINS) algorithm with deformable image registration (DIR) to interface a VR environment for the analysis of cardiac contraction. Thus, the VR-LSFM hybrid platform demonstrates an efficient and robust framework for creating a user-directed microenvironment in which we uncovered developmental cardiac mechanics and physiology with high spatiotemporal resolution.
Fluorescence molecular tomography (FMT) gains increasing interests in deep tissue imaging. Here we report a novel FMT system setup with full angel projections. In this system, a tungsten-halogen lamp is applied as illumination, while a scientific complementary metal oxide semiconductor (sCMOS) is used as a detecting device. With a unique line-pattern illumination and a high sensitivity sCMOS, our FMT system can complete data acquisition over 36 perspective angles along the animal within 10 minutes. We also employ a novel transparent animal bed, which is suitable to hold the animal for long time experiments. Both phantom and in vivo animal experiments have been studied, and our results demonstrate this FMT system has a great potential for small animal study. In addition, our design allows this FMT system to be easily applied in either stand-alone fluorescent systems or combined with other molecular imaging methods.
Confocal laser scanning microscopy (CLSM) has become one of the most important biomedical research tools today due
to its noninvasive and 3-D abilities. It enables imaging in living tissue with better resolution and contrast, and plays a
growing role among microscopic techniques utilized for investigating numerous biological problems. In some cases, the
sample was phase-sensitive, thus we introduce a novel method named laser oblique scanning optical microscopy
(LOSOM) which could obtain a relief image in transparent sample directly.
Through the LOSOM system, mouse kidney and HeLa cells sample were imaged and 10x, 20x and 40x magnify
objective imaging results were realized respectively. Also, we compared the variation of pinhole size versus imaging
result. One major parameters of LOSOM is the distance between fluorescence medium and the sample. Previously, this
distance was set to 1.2 mm, which is the thickness of the slide. The experiment result showed that decreasing d can
increase the signal level for LOSOM phase-relief imaging. We have also demonstrated the application of LOSOM in
absorption imaging modality, when the specimen is non-transparent.
We reported recently that laser oblique scanning optical microscopy (LOSOM) is able to obtain a relief image in
transparent sample directly. To optimize the performance of LOSOM, the parameters such as numerical aperture, the
distance between the specimen and the fluorescent medium and the pinhole size are investigated in this work. A beam
blocker is introduced in light path which enhances dramatically the visualization of local phase difference.