Integrated light-sheet imaging and flow-based enquiry (iLIFE) system for 3D in-vivo imaging of multicellular organism

Abstract

We propose and demonstrate a light-sheet-based 3D interrogation system on a microfluidic platform for screening biological specimens during flow. To achieve this, a diffraction-limited light-sheet (with a large field-of-view) is employed to optically section the specimens flowing through the microfluidic channel. This necessitates optimization of the parameters for the illumination sub-system (illumination intensity, light-sheet width, and thickness), microfluidic specimen platform (channel-width and flow-rate), and detection sub-system (camera exposure time and frame rate). Once optimized, these parameters facilitate cross-sectional imaging and 3D reconstruction of biological specimens. The proposed integrated light-sheet imaging and flow-based enquiry (iLIFE) imaging technique enables single-shot sectional imaging of a range of specimens of varying dimensions, ranging from a single cell (HeLa cell) to a multicellular organism (C. elegans). 3D reconstruction of the entire C. elegans is achieved in real-time and with an exposure time of few hundred micro-seconds. A maximum likelihood technique is developed and optimized for the iLIFE imaging system. We observed an intracellular resolution for mitochondria-labeled HeLa cells, which demonstrates the dynamic resolution of the iLIFE system. The proposed technique is a step towards achieving flow-based 3D imaging. We expect potential applications in diverse fields such as structural biology and biophysics.

Volumetric imaging of human mesenchymal stem cells (hMSCs) for non-destructive quantification of 3D cell culture growth

“…The linear relationship between cell number and cell volume quantified by non-destructive in toto ELIAS provides confirmation that this method could be used to image and characterize samples in an aqueous environment. An ELIAS PAT for on-line monitoring of microcarrier cell cultures would further incorporate microfluidic chips and hydraulic flow to sample microcarriers from the bioreactor to the lightsheet for rapid analysis and back to the bioreactor culture [ 79 , 80 ]. Furthermore, single objective lightsheet systems or oblique plane microscopy could better enable on-line imaging of microfluidic samples as there is only a single sample-facing objective and more space for sample mounting and translation below or above the objective [ 81 , 82 ].…”

Low-cost optofluidic add-on enables rapid selective plane illumination microscopy of C. elegans with a conventional wide-field microscope

“…The contrast obtained from the dendrites of the sensory neurons with the low-cost add-on is comparable with images previously reported using conventional SPIM systems. 10 , 11 , 20 Figure 5(bii-iii) shows the characteristic clustering of neurons inside the brain. The dense neuronal regions of head and tail ganglia 29 express high fluorescent intensity which frequently saturate the acquired images.…”

“…In another approach, on-chip platforms (e.g., microfluidics devices) were integrated into conventional SPIM systems to enable fast fluorescent imaging of C. elegans . 20 While this approach significantly enhanced the imaging speed by acquiring images of C. elegans as they flowed through the light-sheet, the proposed solution was costly because it utilized a standalone SPIM system. As such, development of low-cost, yet rapid, innovations suitable for SPIM imaging of C. elegans are yet to be reported.…”

A Review of Optical Imaging Technologies for Microfluidics

“…There have been many successful examples of microfluidic systems coupled with light-sheet fluorescence microscopy [95][96][97][98][99][100][101][102][103]. This article mainly introduces the research of Memeo et al [104] and Jiang et al [105].…”