Microscópio hiperespectral com aplicações em biomateriais

Abstract

Hyperspectral Imaging (HI) is a technique used to obtain the spectral signature of a sample with spatial resolution, allowing the identification of one or more spectra from the sample. HI is widely used on macroscopic scale for characterization and study in a wide range of applications, from remote sensing of the planet's surface to art conservation and restoration. Recently, the development of HI on a microscopic scale has been achieved, that is, images with spatial resolution about micrometers and with spectral resolution. The application of optical techniques associated to microscopic imaging is a subject of interest for the study of biological materials, especially applications as acessorial tools for pathological diagnosis. Currently, diagnostic methods are mainly based on tissue visual evaluation, which leads to the need for sample preparation procedures that imply financial costs and time for staining and preparing microscopic slides. The literature points out advantages in the use of optical techniques, especially optical spectroscopy, as a possible tool for diagnosing pathologies. In particular, the possibility of using optical spectroscopy associated to microscopic imaging for pre-cancer diagnosis, the stage close to the beginning of cancer development where the tissue morphology does not present observable alterations by the methods widely used for diagnosis. The aim of this work is to present the development of a Hyperspectral Microscope (HM) and its applications for analysis of biological materials. HM is a custom-made microscope coupled to a birefringent-based interferometer used to perform Fourier Transform Spectroscopy (FTS). We present a review of the physical processes that allow the use of birefringent elements in an FTS. We show the experimental details, such as spatial and spectral resolution and calibration routines. We also present results for calibration samples, test samples and the application in histological sections of prostate tissue biopsy.