Spectroscopic analysis of the oxygenation state of hemoglobin using coherent anti-Stokes Raman scattering

Abstract

Abstract.A method for noninvasively determining blood oxygenation in individual vessels inside bulk tissue would provide a powerful tool for biomedical research. We explore the potential of coherent anti-Stokes Raman scattering ͑CARS͒ spectroscopy to provide this capability. Using the multiplex CARS approach, we measure the vibrational spectrum in hemoglobin solutions as a function of the oxygenation state and observe a clear dependence of the spectral shape on oxygenation. The direct extraction of the Raman line shape from the CARS data using a maximum entropy method phase retrieval algorithm enables quantitative analysis. The CARS spectra associated with intermediate oxygenation saturation levels can be accurately described by a weighted sum of the fully oxygenated and fully deoxygenated spectra. We find that the degree of oxygenation determined from the CARS data agrees well with that determined by optical absorption. As a nonlinear optical technique, CARS inherently provides the 3-D imaging capability and tolerance to scattering necessary for biomedical applications. We discuss the challenges in extending the proof of principle demonstrated to in vivo applications.

Real‐time molecular assessment on oxidative injury of single cells using Raman spectroscopy

“…However, improvement might be potentially achieved with the introduction of coherent or resonant enhancement techniques that have been well demonstrated in selected biological systems. [27] …”

Chemoselective imaging of mouse brain tissue via multiplex CARS microscopy

“…CARS has been applied in a large field of medical applications ranging from the identification of microbial cells, high resolution imaging of human aorta-tissue, time resolved observations of HELA cells, up to real time monitoring of blood oxygenation level [3–7]. In spite of its success, CARS has been used only rarely for the identification of pathologic tissue alterations [8–10].…”

Raman Spectroscopy of Blood and Blood Components

“…The oxygenation of hemoglobin has continued to be of interest, and enhancement Raman spectroscopy techniques other than RRS have been applied. Coherent anti-Stokes Raman scattering (CARS) acquired quantitative measurements of oxygen saturation that agreed well with optical absorption analyses, 37 and one of the most highly cited hemoglobin studies was a SERS experiment that obtained spectra from single hemoglobin molecules attached to 100 nm sized immobilized silver particles. 38 Raman Spectroscopy Studies of Intact Red Blood Cells Intracellular Hemoglobin.…”