Label-free assaying of testosterone and growth hormones in blood using surface-enhanced Raman spectroscopy

This work reports the potential use of surface-enhanced Raman spectroscopy (SERS) in rapid, label-free assaying of testosterone (TE) and growth hormone (GH) in whole blood. Biomarker SERS spectral bands from the two hormones (TE and GH) in intentionally spiked water for injection and in male Sprague-Dawley (SD) rat’s blood are reported. These concentration-sensitive Raman bands as deduced through Principal Component Analysis (PCA) and Analysis of Variance (ANOVA), were centered around 1490 and 1510 cm⁻¹ for GH, 1614 and 1636 cm⁻¹ for TE; and 684 cm⁻¹ for the hormone mixture (GH+TE) in blood. These bands exhibited significant intensity changes with the concentration of GH and TE hormones in blood. They were tentatively assigned to C-C stretching (684, 786, 856, 1614 and 1636 cm⁻¹), CH₂ bending (1490 cm⁻¹) and CH₂ stretching (1510 cm⁻¹). These bands may be used in SERS assaying of the respective hormones in blood using a customized and calibrated Raman system thus utilizing the strengths of the SERS method that include, being label-free, rapid (<1 min), chemically specific, minimal sample preparation among others. Besides, the method may potentially be used in detecting abuse of TE and GH in sports where they are often abused concurrently.