The BSISB Program Imaging Technologies at a Glance
BSISB develops facilities, training and support for investigating cellular chemistry and function by synchrotron radiation–based Fourier transform infrared (SR-FTIR or sFTIR) spectromicroscopy, time-resolved sFTIR spectromicroscopy, synchrotron Infrared Nano-Spectroscopy (SINS), and 3D synchrotron FTIR micro-tomography (sFTIR µTomography).
Other complementary microscopy and spectroscopic imaging methods include fluorescence microscopy, Raman microscopy, simultaneous optical hyperspectral sample imaging and spatially-resolved AIRLAB mass spectrometry.
Aqueous environments hinder sFTIR’s sensitivity to bacterial activity, but BSISB’s integrated in-situ microfluidic systems circumvent the water-absorption barrier while allowing cells to maintain their functions.
These systems have enabled real-time chemical imaging of bacterial activities in biofilms and facilitated comprehensive understanding of structural and functional dynamics in a wide range of microbial systems.
BSISB continues to build new chemical imaging capabilities, advance user-specific microfluidic systems and automation, and develop new software and machine learning for accelerating data analysis.
We are also developing a bi-modal chemical imaging technique that combines sFTIR spectromicroscopy with spatially resolved mass spectrometry. A key benefit of the current BSISB program is enabling investigators to use synchrotron FTIR spectromicroscopy for monitoring living cells or tissues under native-like conditions with the ability to induce environmental perturbations.From these infrared absorption data, spatially- and temporally-resolved chemical information, including the distributions and relative abundances of the classes of chemicals such as proteins, lipids, carbohydrates, or metabolites, is obtained. However, these infrared data lack sufficient chemical specificity for unique identifications. High-resolution mass spectrometry (MS) can make possible more complete identification of the full range of molecules involved in functional metabolism, including elemental composition obtained by accurate mass measurements and structural information gained from fragmentation products formed in tandem mass spectrometry measurements.
Currently, there is no practical way to bridge the non-destructive, ambient chemical monitoring capabilities of SIR spectromicroscopy with efficient, spatially-resolved analysis by mass spectrometry.
Common question about BSISB :
What is synchrotron infrared light and why is it useful?
Synchrotron infrared light is simply infrared light that is produced from a synchrotron. Although most synchrotron light sources are optimized to produce X-ray and vacuum ultraviolet radiation, they also produce broad band radiation in the infrared region. The primary advantage of synchrotron infrared radiation is its brightness. Because the light originates from a small packet of electrons, the source can be treated as a point source. Thus, infrared light from a synchrotron can be easily collimated and/or focused to diffraction limited spot sizes (~1-10 μm), allowing high spatial resolution (infrared spectromicroscopy) and high spectral resolution.
More Far-IR Flux
What are the current scale or resolution ranges of the technologies the BSISB program develop and/or use?
- The label-free broadband Fourier Transform Infrared (FTIR) microscopy is developed and used to measure the chemistry of biological processes in specimens up to 30 µm thick and 300 µm wide, with a spatial resolution across the mid-infrared wavelength scales from 2 to 15 µm (from bacteria/archaea, trace biofilms, to plant cells), providing vibrational intensity maps that visualize contributions from molecular functional groups in a specimen.
- The signal-to-noise of FTIR spectromicroscopy increases at least 100 fold by switching the mid-infrared source from a commercial thermal element to a bright accelerator-based Synchrotron Infrared (SIR) beam coupled to a single point detector.
- A current focus of our group is to construct a homogeneously illuminated full-field Synchrotron Infrared (SIR) spectral imaging platform to expand and modulate the SIR beam to fill a Focal Plane Array (FPA) using adaptive optics components.
- Another current focus is to use structured illumination to improve the spatial resolution two fold, between 1 and 7 µm.