The Laser Biomedical Research Center has the following instruments available to outside
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Portable Clinical Raman Instrument
Our custom-built clinical Raman instrument is capable of collecting Raman spectra from biological tissues over the fingerprint range 400-1960 cm-1. The clinical Raman system measures approximately 32" x 17" x 10" and sits on a low wheeled platform. The instrument uses an 830 nm diode laser, delivered through a custom made fiber-optic probe, to excite Raman scattering within the biological sample. The probe is 4 m long and is 2 mm in overall diameter. The same probe collects light (with the probe tip in contact with the tissue sample). The collected Raman signal is detected using spectrograph with a CCD detector thermoelectrically cooled to -70oC for high sensitivity Raman measurements. Integrated software (developed in LabVIEW and MATLAB) enables rapid collection of Raman spectra (1s) and real-time analysis of the spectral parameters.
Multimodal Microscopy System
The multi-modality imaging setup, built on an inverted microscope, features following imaging modalities: confocal Raman imaging, confocal reflectance imaging, Hilbert phase microscopy, and bright-field imaging. A 785 nm source is used for both confocal reflectance and confocal Raman imaging. A water immersion objective lens (60X/1.20 NA) is used for high-resolution imaging. A dual-axis galvanometer scanner is utilized for beam scanning. XY positioning for different fields of view can be achieved by a motorized stage. Coarse and fine adjustment of sample focus is done using a piezo actuator combined with a differential micrometer. The confocal Raman signal is detected using an imaging spectrograph whereas the confocal reflectance signal is detected using a photomultiplier tube. Labview software is used for instrument control and data acquisition. The CMOS camera is used to capture both the interferograms for Hilbert phase microscopy as well as bright-field images.
Tomocube - 3D Holographic and Fluorescence Microscope
The LBRC is also equipped with "Tomocube HT2" - a commercial microscopy unit that enables 3D holographic as well as fluorescence imaging of biological cells and thin tissue slices. The instrument utilizes optical diffraction tomography algorithm, which allows quantification of three-dimensional (3D) refractive index distribution of sub-cellular structures within the sample under observation. Holographic imaging specifically provides structural and biomechanical information including cell drymass, morphology, and dynamics of the cellular membrane. The 3D fluorescence imaging, which utilizes 3 channel LEDs (385nm, 470nm, 570nm), provides additional complementary information about the sample. Tomocube features lateral and axial resolution of 220nm and 700nm, respectively, with 80 µm x 80µm field-of-view. Imaging speed for two-dimensional (2D) quantitative phase imaging is up to 150 frames per second, while 3D holographic imaging speed up to 1.7 tomograms per second is possible.
Spectroscopic Tissue Scanner
The LBRC has developed a portable tissue scanner to image large (8cm x 8cm) tissue specimens in a clinically acceptable time frame (less than 20 minutes) with 0.25 mm spatial resolution. Figure 4 shows the schematic of tissue scanner, which employs unitary multimodal optical fiber probes for point spectroscopy measurements. The two fiber probes acquire diffused reflectance spectroscopy (DRS) intrinsic fluorescence spectroscopy (IFS) signals, respectively. The tissue scanner has long traveling range XY-translation stage for wide area imaging. Excitation beam spot size at the surface of a tissue sample is about 1 mm. Total scanning time for the tissue sample depends on the choice of parameters such as excitation power, integrating time, spatial resolution, and field-of-view, which can be adjusted according to tissue type and clinical need.