| Description |
Modern medicine would benefi t from the pursuit of new, more speci fic and easier to implement diagnosis tools. In recent years, Raman scattering, surface-enhanced Raman scattering and fluorescence spectroscopy have proven to be successful diagnostic techniques for a wide range of diseases including atherosclerosis, kidney stones, bone diseases, diabetes, and a wide collection of neoplasms. Optical spectroscopy has several advantages over more traditional diagnostic methods (i.e., histopathology, quantitative PCR, etc.) such as faster data analysis, nonspecifi c sample preparation, nonspecifi c labels/reagents/antibodies usage requirements, and immediate on-site implementation. In the present work, label-free in vitro fluorescence and surface enhanced Raman scattering (SERS) spectroscopy have been used to di fferentiate between blood cells of patients aff ected with myeloproliferative neoplasms (MPN) and those of healthy subjects. The SERS technique has also been applied to hemoglobin variants as well as to serum obtained from patients affected with chronic heart failure who positively or negatively responded to the seasonal influenza vaccine. We found that spectral ratios of the background fluorescence intensity that accompanies the SERS spectra of granulocytes serve as excellent markers for the presence of MPNs. In addition, we also found expression dysregulation of two hypoxia induced factor regulated genes, which correlates with our results obtained by SERS spectroscopy assay in MPN patients and supports the presence of the Warburg e ffect in MPNs. We hypothesize that SERS measures metabolic change in granulocytes through two possible mechanisms: (i) Changes in dielectric properties of the environment surrounding the silver-cell interface; and (ii) changes in flavinadenine dinucleotide concentrations, which in turn changes the relative contribution of the auto uorescence to the emission spectrum. These hypotheses are supported by SERS measurement of 2-deoxy-D-glucose incubated granulocytes, where the emission spectra show a similar behavior as observed in the SERS spectra of controls and patients. Using SERS spectroscopy in combination with multivariate analysis (e.g., principal component analysis) and classi fication algorithms (e.g., support vector machines), we are able to distinguish among hemoglobin variants S, C and E and traits FS and FE, as well as seasonal infuenza vaccine responders and nonresponders within a population of patients su ffering from chronic heart failure. The results presented here may have an extraordinary impact on the diagnostics of patients having Myeloproliferative Neoplasms, as well as on the health care management of patients aff ected with hemoglobinopathies and chronic heart failure. |
