Surface-enhanced Raman spectroscopy signatures of an RNA molecule: An aptamer that binds to α_vβ₃ integrin

Raman spectroscopy is a useful technique for identifying molecules by their unique vibrational signatures. Surface-Enhanced Raman Spectroscopy (SERS) is capable of routinely amplifying the Raman signal by a factor of >10 ⁷ through the use of a plasmon-generating substrate. This study investigated the SERS spectrum of Apt-α_vβ₃, an 85-base long RNA molecule generated specifically for binding to the α_vβ₃ integrin on cellular membranes. The Ag nanorod (AgNR) SERS substrate used in this study was fabricated using oblique angle deposition (OAD). Apt-α_vβ₃ at 4 μM concentration was imaged on a patterned multiwell AgNR SERS chip using a Renishaw Ramascope 2000 spectrometer with 2.3 mW power and 514 nm excitation wavelength. The majority of the peaks lie in the 800-1600 cm^-1 range consistent with previously published RNA/DNA Raman spectra. Peaks corresponding to vibrational modes of guanine, cytosine, adenine and uracil can all be identified. These results demonstrate the effectiveness of the AgNR SERS substrate in obtaining the Raman spectra of biological samples. Additionally, the unique Raman signature of Apt-α_vβ₃ was determined.