We report on a novel fabrication approach to build multilayered optical tissue phantoms that serve as independently validated test targets for axial resolution and contrast in scattering measurements by depth-resolving optical coherent tomography (OCT) with general applicability to a variety of 3D optical imaging platforms. We implement a combinatorial bottom-up approach to prepare monolayers of light-scattering microspheres with interspersed layers of transparent polymer. A dense monolayer assembly of monodisperse microspheres is achieved via a combined methodology of polyelectrolyte multilayers (PEMs) for particle-substrate binding and convective particle flux for two-dimensional crystal array formation on a glass substrate. Modifications of key parameters in the layer-by-layer (LBL) polyelectrolyte deposition approach are applied to optimize particle transfer from a glass substrate onto an elastomer while preserving the relative axial positioning in the particle monolayer. Varying the dimensions of the microspheres and the thickness of the intervening polymer layers enables different spatial frequencies to be realized in the transverse dimension of the solid phantoms. Step-wise determination of the phantom dimensions are performed independently of the optical systems for precise spatial calibration and independent validation.
Citation: Biomedical Optics Express
Pub Type: Journals
calibration, optical coherence tomography, particle assembly, phantom, polyelectrolytes, resolution, scattering