University of California Davis Health
Developers: Richard Levenson, Farzad Fereidouni, and Stavros Demos
MUSE microscopy (microscopy with ultraviolet surface excitation) is based on two properties of 280 nm UV light: (1) UV light in this range penetrates tissue specimens to a depth of no more than about 10 microns, a thickness only slightly greater than that of a standard histology slide tissue section; and (2) UV light at this wavelength can excite, and cause to emit in the visible range, a large variety of inexpensive fluorescent stains that can mimic (and extend) the tissue specificity of hematoxylin and eosin (H&E) stain. The low penetration depth limits excitation to a thin layer and removes the usual requirement for tissue sectioning. Using color conversion algorithms, the resulting fluorescent images can be converted, in real time, to resemble that seen with conventional pathology microscopy.
The design is based on UV LEDs, conventional glass (not UV-transparent) objectives, and color cameras. There is no need for lasers, emission or excitation filters, or the computational input required by other methods. Sample preparation is straightforward, consisting of a brief (seconds) stain of tissue and a brief wash.
Light microscopy for tissue diagnostics, the industry standard, typically relies on thin-sectioned formalin-fixed specimens and absorbance-based stains (such as H&E) that are useful for general morphological visualizations. But those stains provide only a limited color gamut that reveals little about the molecular constitution of the sample. Moreover, thin-cut specimens on slides represent a narrow and flat planar slice of a complicated 3D sample. MUSE overcomes both of these limitations. First, a number of rapidly applied fluorescent tissue stains can generate multiple and potentially useful color signals that convey more information than is available with H&E. Secondly, since MUSE views the surfaces of tissues, it can capture 2.5-dimensional topographical information.
There is no substitute for tissue sampling (biopsies) followed by histopathology. The light microscopy methods used to examine these biopsies have not changed significantly in over a century. MUSE can replicate, and in some cases improve upon, conventional transmission light microscopy, but its ability to eliminate the need for histological slide-preparation is likely to be of greater significance. MUSE has the potential to fundamentally change how diagnostic microscopy is practiced.