Vibrational spectroscopic study of newly developed self-forming lipids and nanovesicles.

We present the first experimental study of self-forming synthetic nanovesicles, trademarked as QuSomes{\texttrademark}, using vibrational spectroscopic techniques namely near-infrared (NIR) and laser tweezers Raman spectroscopy. Raman spectra of these new artificial nanovesicles suspended in Phosphate Buffered Saline (PBS) have been obtained by using an inverted confocal laser-tweezers-Raman-microscopy system in the spectral range of 3100 to 500 cm$^{-1}$. This spectrometer works with an 80 mW diode-pumped solid-state laser, operating at a wavelength of 785 nm in the TEM$_{00}$ mode. The laser is used both for optical trapping and Raman excitation. Similarly, NIR absorption spectra of these novel nanovesicles have been recorded in the spectral range of 9000-4800 cm$^{-1}$ by using a new miniaturized micro-mirror spectrometer based on micro-optical-electro-mechanical systems (MOEMS) technology. In this work, we have found that the most prominent bands in the studied spectral region of Raman spectra are dominated by vibrational modes arising from C-C and CH$_{2}$ bonds. Similarly, NIR spectra are primarily assigned as first and second overtone of C-H stretching mode and second overtone of C=O stretching mode. These spectroscopic techniques have proven to be an excellent tool to establish the fingerprint region revealing the molecular structure and conformation of QuSomes{\texttrademark} nanoparticles.