Abstract
A compact endomicroscope is the only solution for transferring second harmonic generation (SHG) imaging into in vivo imaging and real time monitoring the content and structure of collagen. This is important for early diagnoses of different diseases associated with collagen change. A compact nonlinear endomicroscope using a double clad fiber (DCF) is newly employed in SHG imaging. The experiment shows the core of the DCF can maintain the linear polarization of the excitation laser beam in particular directions, and the degree of polarization of the excitation laser beam directly affects signal to noise ratio of SHG imaging. The nonlinear endomicroscope can display clear three dimensional (3D) SHG images of mouse tail tendon without the aid of contrast agents, which reveals the collagen fiber structure at different depths. The high resolution of SHG imaging from the endomicroscope shows that SHG imaging can reveal additional information about the orientation and degree of organisation of proteins and collagen fibers than two-photon-excited fluorescence imaging. Therefore SHG imaging offers endomicroscopy with additional channel of imaging for understanding more about biological phenomena.
Highlights
Second harmonic generation (SHG) is a process where two photons simultaneously interact with non-centrosymmetrical structures without absorption, producing radiation at exactly half of the excitation wavelength [1,2,3]
A compact endomicroscope is the only solution for transferring second harmonic generation (SHG) imaging into in vivo imaging and real time monitoring the content and structure of collagen
This is important for early diagnoses of different diseases associated with collagen change
Summary
Second harmonic generation (SHG) is a process where two photons simultaneously interact with non-centrosymmetrical structures without absorption, producing radiation at exactly half of the excitation wavelength [1,2,3]. The SHG excitation is a nonlinear process and the signal intensity is directly proportional to the square of the excitation intensity This provides SHG imaging with intrinsic confocality and deep sectioning in complex tissues. To date almost all research in SHG imaging has been carried out using a conventional bench top microscope system Such a system does not provide the adjustment flexibility needed for in vivo imaging, where specimens need to be mounted on the microscopy stage, limits the system’s use. Experimental results show that the core of a double clad fiber (DCF) which the endomicroscope uses has a “polarization maintaining” feature in particular directions Using this “polarization marinating” feature, the nonlinear endomicroscope can observe clear 3D collagen structure of a mouse tail tendon within a depth of 88 μm. High resolution SHG imaging from the endomicroscope has shown more micro-structure information of biological tissue than two-photon fluorescence imaging
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
