The Sharma Raman Lab published their work “Direct Surface Enhanced Raman Spectroscopic Detection of Cortisol at Physiological Concentrations” in Analytical Chemistry.
Josh Moore is the first author on this piece and recently earned his PhD in the Chemistry program.
Cortisol is an important steroid hormone in vertebrate physiology and plays a role in acute and chronic stress response. Current methods for determination of cortisol concentrations in biofluids require extensive sample preparation and long run times. Raman spectroscopy is an attractive alternative because analysis is rapid and non-destructive to the sample.
The Sharma Lab has developed a surface-enhanced Raman spectroscopy (SERS)-based method for detection of cortisol in ethanol that shows a sigmoidal concentration response and a limit of detection of 177 nanomolar, which is in the physiologically relevant range. The method can be applied to more complex solvent environments through the use of multivariate analysis techniques, where principal components analysis (PCA) demonstrates a linear separation according to cortisol concentration in a serum mimic. “We are, to our knowledge, the first group to report on the detection of cortisol using label-free SERS, which does not require a Raman reporter molecule to obtain signal,” Moore said.
The Sharma Lab published their work “Surface-enhanced spatially-offset Raman spectroscopy (SESORS) for detection of neurochemicals through the skull at physiologically relevant concentrations” in Analyst.
Detection techniques for neurotransmitters that are rapid, label-free, and non-invasive are needed to move towards earlier diagnosis of neurological disease. Surface-enhanced Raman spectroscopy (SERS) allows for sensitive and selective detection of target analytes. The combination of SERS with spatially offset Raman spectroscopy (SORS) in a technique termed surface enhanced spatially offset Raman spectroscopy (SESORS) permits a sensitive and selective detection of neurotransmitters through the skull.
In this piece, the group presents the SESORS detection of individual neurotransmitters and mixtures of neurotransmitters at physiologically relevant concentrations, while also establishing limits of detection.