Raman spectral signatures of human liver perfusates correlate with oxidation reduction potential

Biomarkers for the early detection of liver toxicity are crucial in drug development for assessing the safety of a new drug. Oxidation reduction potential (ORP) is an overall measure of the oxidative stress to which a biological component is subjected and correlates with organ dysfunction. Raman spectroscopy is a non-invasive method that we employed to analyze the perfusates of five normothermic human livers perfused with the known toxin α-naphthylisothiocyanate. Spectral signatures were generated using principle component analysis (PCA) coupled with stepwise linear regression of the first several PCA coefficients to the ORP. The Raman signatures correlated to the measured ORP with an r2 of 0.854. This study demonstrated the utility of this technique in determining the presence of liver toxicity as reflected by increasing ORP. Real-time, non-invasive monitoring of normothermic perfusates of human livers using processed Raman spectra has the potential to predict drug toxicity and organ viability for transplantation.