Coherent anti-Stokes Raman scattering (Cars) microscopy allows rapid and non-perturbative imaging of biological specimens with chemical selectivity
Harvard University's Office of Technology Development (OTD) has licensed its Cars microscopy technology to Leica for use in the company's confocal microscopes.
The technology was developed in the lab of Xiaoliang Sunney Xie, professor of chemistry and chemical biology at Harvard.
"This technology has far-reaching implications for helping advance important biomedical research," stated Isaac Kohlberg, chief technology development officer, Harvard University.
"Our agreement with Leica Microsystems is aligned with our strategy to partner with the best and most expert companies who, like us, are dedicated to excellence and quality".
Martin Haase, managing director at Leica Microsystems, emphasised: "We are excited about this collaboration and envision to jointly drive technology and product development for improved imaging capabilities of our clients in the life science research space.
"This type of collaboration is in full alignment with Leica Microsystems's strategy of open innovation and will strongly foster commercialisation of new and groundbreaking technologies".
The contrast in Cars microscopy arises from the intrinsic vibrations of molecules.
Every molecule has one or more chemical bonds, the bending or stretching of which have characteristic vibrational frequencies that depend on the bond length and strength.
For example, lipids, a primary component of fat, contain carbon-hydrogen bonds, which vibrate at certain distinct frequencies.
Cars microscopy 'tunes' into these characteristic frequencies to build chemically-selective images with extremely high sensitivity in living cells or organisms.
To image a specimen, such as tissues or cells, Cars microscopy utilises two highly focused laser beams at different frequencies.
By setting the difference between the two laser frequencies equal to the frequency of vibration of a particular chemical bond, molecules with that bond are made to vibrate coherently.
This causes the sample to emit at a new frequency (called the anti-Stokes frequency) from the laser focus.
An image is created by scanning the beams over the sample and detecting the intensity of the emitted anti-Stokes light at each position.
In this way, one can map the concentration of the molecule of interest (eg, lipid) throughout the tissue, or within a cell with 300nm lateral resolution.
The method offers much higher time resolution than other vibrational imaging techniques, allowing movies of biological activity and chemical processes to be taken within a living cell or organisms.
By using excitation lasers at near-infrared wavelengths, which can penetrate deep into tissue, Cars microscopy can reach a depth of nearly 0.3mm below the surface.
Efforts are underway to extend Cars microscopy for not only cell biology applications, but also disease diagnostics and real-time surgical guidance.