Nano-PTV Using Confocal Microscopy

A conventional microscopy and confocal microscopy was used to enable nano-particle tracking using a three-dimensional (3-D) diffraction image pattern caused by an optical aberration. The Point Spread Function (PSF) of a particle image is known as a function of a defocus distance from a focal plane. Using the PSF of nano-particles, particle’s x and y positions as well as z-position can be obtained. A dry objective lens (40X, 0.75NA) is used to detect diffraction patterns of 500-nm fluorescent micro-spheres suspended in water solution inside a 100-μm square micro-tube. The purposes of this presented study are to investigate experimentally the 3-D PSF of fluorescent nano-particle in thick specimen and to develop the 3-D particle tracking technique using 3-D diffraction images of conventional microscopy and CLSM.