Detection of glutamate in the eye by Raman spectroscopy

• Published in: Journal of biomedical optics Vol. 8; no. 2; p. 167
• Main Authors: Katz, Al, Kruger, Erik F, Minko, Glenn, Liu, C H, Rosen, Richard B, Alfano, Robert R
• Format: Journal Article
• Language: English
• Published: United States 01.04.2003
• Subjects: Animals; Cornea - chemistry; Cornea - drug effects; Cornea - metabolism; Diabetic Retinopathy - chemically induced; Diabetic Retinopathy - metabolism; Eye - chemistry; Eye - drug effects; Eye - metabolism; Glaucoma - chemically induced; Glaucoma - metabolism; In Vitro Techniques; Lens, Crystalline - chemistry; Lens, Crystalline - drug effects; Lens, Crystalline - metabolism; Sodium Glutamate - administration & dosage; Sodium Glutamate - analysis; Sodium Glutamate - chemistry; Sodium Glutamate - metabolism; Spectrum Analysis, Raman - instrumentation; Spectrum Analysis, Raman - methods; Swine; Tissue Distribution; Vitreous Body - chemistry; Vitreous Body - drug effects; Vitreous Body - metabolism
• ISSN: 1083-3668
• DOI: 10.1117/1.1559726

Raman spectroscopy is used to detect glutamate in the eye. Glutamate, a by-product of nerve cell death, is an indicator of glaucoma and diabetic retinopathy. The Raman spectra of ex vivo whole porcine eyes and individual components (lens, cornea, vitreous) are measured and characterized. Monosodium glutamate is injected into the eyes to simulate disease conditions, and the contribution to the Raman spectrum due to the presence of glutamate is identified. The Raman spectra from the native eye is dominated by vibrational modes from proteins in the lens. An optical system is designed to optimize collection of signal from the vitreous, where the glutamate is located, and reduce the Raman from the lens. Two vibrational fingerprints of monosodium glutamate are detected at 1369 and 1422 cm(-1), although the concentrations are much above physiological concentrations.