Combined confocal Raman and quantitative phase microscopy system for biomedical diagnosis

Abstract

We have developed a novel multimodal microscopy system that incorporates confocal Raman, confocal reflectance, and quantitative phase microscopy (QPM) into a single imaging entity. Confocal Raman microscopy provides detailed chemical information from the sample, while confocal reflectance and quantitative phase microscopy show detailed morphology. Combining these intrinsic contrast imaging modalities makes it possible to obtain quantitative morphological and chemical information without exogenous staining. For validation and characterization, we have used this multi-modal system to investigate healthy and diseased blood samples. We first show that the thickness of a healthy red blood cell (RBC) shows good correlation with its hemoglobin distribution. Further, in malaria infected RBCs, we successfully image the distribution of hemozoin (malaria pigment) inside the cell. Our observations lead us to propose morphological screening by QPM and subsequent chemical imaging by Raman for investigating blood disorders. This new approach allows monitoring cell development and cell-drug interactions with minimal perturbation of the biological system of interest.

Biomedical applications of holographic microspectroscopy [Invited]

“…Nonetheless, the use of additional exogenous agents, such as microspheres and nanoparticles, can be advantageous in these applications [110][111][112]143,144]. Polarization-sensitive imaging [145,146] or Raman spectroscopy [147] also can be employed in holographic microspectroscopy as an additional modality to include birefringence imaging contrast in addition to optical dispersion.…”

Raman spectroscopy: techniques and applications in the life sciences

“…Atomic force microscopy [152] and quantitative phase microscopy [153] have been used to measure the thicknesses of cells. Angle-resolved elastic scattering has been used to measure the sizes of sub-cellular organelles [154,155].…”

A simple and rapid detection of tissue adhesive-induced biochemical changes in cells and DNA using Raman spectroscopy

“…The intracellular information about nucleic acids, proteins and other components, as well as their conformation, can be probed using variations in spectral shape or intensity [11][12][13][14][15]. Therefore, Raman spectroscopy can distinguish between samples, and has been explored for the analysis of disease with multivariate statistical analysis, which has shown high sensitivity and specificity for diagnostic applications [16][17][18][19]. More recently, Huang et al employed a novel image-guided Raman endoscopy technique developed for the Raman measurement of in vivo gastric tissue within 0.5 sec during clinical endoscopic examination [20].…”