Simultaneous label-free autofluorescence multi-harmonic microscopy (SLAM) is a new intravital microscopy (IVM) technique that offers real-time imaging of living tissue without the use of chemical stains or dyes. IVM was first demonstrated in the late 1800s and has been widely used along with molecular markers, but now after a label-free IVM technique has been demonstrated, the technology offers significant potential not only for pathology, diagnosis and disease monitoring but for surgical applications as well.

SLAM was developed and demonstrated by researchers at the University of Illinois. They published their study “Intravital imaging by simultaneous label-free autofluorescence-multiharmonic microscopy” in Nature Communications.

They developed SLAM using a custom-designed, single-excitation source centered at 1,110 nm, with an ultra-fast pulse rate of 10 MHz. They demonstrated the versatility and efficiency of SLAM as they were able to track a range of cellular events in vivo including vesicles, tumor cells and other living tissue.

SLAM offers high-resolution, real-time imaging of living tissue. The advantages of this label-free IVM technique include:

• The ability to simultaneously excite and capture both auto-fluorescence and harmonic generation from a range of living tissues
• Long-term observation is now possible due to the use of longer wavelength excitations and the lower average incident power estimated at only 14 mW