NOVEL NEAR INFRARED CONFOCAL MICROSCOPY FOR 3D IMAGING OF THICK BIOLOGICAL TISSUE

Abstract

By extending the traditional visible light confocal imaging into the near infrared window (NIR window, 600-1700nm), greater penetration depths can be achieved, owing to low autofluorescence within this optical range and reduced scattering of long wavelength photons. This thesis discloses the implementations and applications of two different types of novel NIR confocal laser scanning microscopes. First, we elaborate on the development of a NIR based upconversion confocal microscope, which is suitable for cellular imaging with lanthanide-based upconverting nanoparticles (UCNPs) with NIR-II excitation and NIR-I emission. A penetration depth of 570 μm can be achieved in a skin mimicking scattered tissue phantom. Secondly, we present a novel design of a confocal microscope tailored for imaging in the NIR-II window. The outstanding penetration depth (up to 800 μm) and high sensitivity of our confocal setup have been demonstrated with a series of bioimaging experiments.