SERS analysis on exosomes using super-hydrophobic surfaces

Exosomes are very small vesicles that are shed from a variety of cell types. They are present in body fluids comprising blood, urine and ascites, and they hold the potential to serve as indicators in the diagnosis, prognosis and surveillance of a variety of health conditions. In consideration of this, there is broad interest worldwide in deriving and understanding their biochemical composition. Here, small drops of solutions containing exosomes, isolated from either healthy (CCD841-CoN) or tumor (HCT116) colon cells, were manipulated using super-hydrophobic surfaces (SHSs) decorated with nano-geometry based photonics structures. SHSs are surfaces with superior properties, including a reduced friction coefficient, on account of which they can be used to control diluted solutions of biological or medical interest. The combination of this technology with optical resonance phenomena, open up terrific opportunities in the detection, analysis or characterization of biological compounds. Therefore, exosomes were conveniently concentrated and conveyed onto the Surface Enhanced Raman Spectroscopy (SERS) active areas of the substrate, whereby they were analyzed and characterized with extreme precision. Results indicate a difference in the concentration of some biological compounds, and namely: exosomes derived from healthy cells exhibit higher intensities of the peaks corresponding to lipids vibrations, while exosomes extracted from tumor cell lines exhibit a richer RNA content.