We developed a label-free fluorescence lifetime imaging microscopy (FLIM) to quantify the metabolic state of tumor spheroids. We obtained label-free 3D FLIM images from different focal plane of cancer (MCF7) spheroids for 4 different spectral bands which was segregated by the custom-made spectral resolving unit. To obtain optically sectioned images, we used an optical fiber instead of a spatial filter. Statistical analyses showed that the signals acquired by FLIM—fluorescence intensity and lifetime—reflected well the metabolic state of cancer cells constituting spheroids. These results demonstrated the potential for quantitative measurement of the cellular metabolism in a label-free, non-destructive manner.

Near-Infrared wide-field Fluorescence Lifetime Imaging (FLI) has become an increasingly popular method due to its unique specificity in sensing the cellular micro-environment and/or protein-protein interactions via FRET, but the approach is still challenging due to inefficient detection modules. Here, we report on the characterization of a large gated SPAD array, SwissSPAD2, towards in vivo preclinical imaging of FLI-FRET. Fluorescence decay fitting as well as phasor analysis are used to demonstrate the ability of SwissSPAD2 to accurately quantify short lifetimes and associated lifetime parameters in both in vitro and in vivo experiments, in full agreement with gated ICCD measurements.

In this work, we developed a new method for high throughput imaging flow cytometry, using diffractive optics elements to generate linear laser spot array for illumination, and single-pixel detectors for detection. The illumination spots are arranged in a line at equal intervals and form a small angle with the direction of the cell movement. When the cell passes through the illumination area, the two-dimensional information of the cell's fluorescence and scattered intensity profile is encoded into signals detected by the PMTs. Fluorescence and scattering imaging were experimentally demonstrated for beads and cells traveling at a velocity of 4.7 m/s in a microfluidic chip, with a resolution of 1 μm and a maximum throughput of 5000cell/s.

we introduce automated serial OCM toward statistical 3D digital histopathology. Our research is the extension of previous work in order to enhance the process of imaging acquisition. Our approach has three unique features, (1) surface tracking, (2) single body and automated system combined vibratome and microscopic imaging head, and (3) selection of magnification. In validation test, various mouse organs were imaged and quantified at the region of interest which presented less labor and shorten image acquisition time compared to previous works.

Chinese hamster ovary (CHO) cells are the most widely used cell line for the recombinant expression of human therapeutics. To investigate a select cell line monoclonal antibody production, we monitor NAD(P)H, a crucial enzymatic cofactor, and an auto-fluorescent bio-marker, with two-photon fluorescence lifetime imaging microscopy (2P-FLIM). This represents a high-resolution, label-free technique for longitudinally characterizing a changing environment (if any) during metabolic transitions. 2P-FLIM analysis of NAD(P)H in four different CHO cell lines helps us predict productive cell types from others. A detailed single cell analysis is also presented that can separate cell types based on optical and morphological classification.

Steady-state and time-resolved photoluminescence measurements are powerful tools for getting in-depth information about the nature, characteristics, and environment of proteins and small biomolecules. The spectral region between 280 – 300 nm is significant for biology, life and materials science. Here we present the differences in steady state and time-resolved fluorescence measurements when using a regular pulsed UV-LED and new pulsed high-power UV-LED with a photoluminescence spectrometer.

We report the advancement of magnetomotive micro-optical coherence tomography (µOCT) technology for mapping the cystic fibrosis (CF) mucus viscoelastic properties in situ. We conducted pilot experiments in ex-vivo CF ferret trachea and wild-type swine trachea with a new magnetomotive system design. The system utilizes an electromagnet to drive magnetic nanoparticles with constant and uniform magnetomotive force in the field of view of µOCT. Preliminary results showed that the new system enhances individual magnetic micro-particle tracking and enables the measurement of the viscoelastic properties in different compartments of the mucus.

Bio-integrated lasers, that are lasers implanted into cells and tissues, are gaining interest from the research community. Here we show how microlasers and microcavities based on whispering gallery modes can be used for sensing different processes in biological materials including inside cells. By making microcavities of a predefined size they can also be used to encode some information and for cell tracking. Sensing and tracking can be applied to highly scattering tissues.

Dynamic full-field optical coherence microscopy (DFFOCM) was used to characterize the intracellular dynamic activities and cytoskeleton of HeLa cells in different viability states. HeLa cell samples were continuously monitored for 24 hours and compared with histological examination to confirm the cell viability states. The averaged mean frequency and magnitude observed in healthy cells were 4.79±0.5 Hz and 2.44±1.06, respectively. In dead cells, the averaged mean frequency was shifted to 8.57±0.71 Hz, whereas the magnitude was significantly decreased to 0.53±0.25. This cell dynamic activity analysis using DFFOCM is expected to replace conventional time-consuming and biopsies-required histological or biochemical methods.