Description
Surface enhanced Raman spectroscopy (SERS) is a promising method for accessing the wealth of information carried by extracellular vesicles (EVs). However, ensuring analyte adsorption onto the enhancing nanostructure and concentration in local electromagnetic hot-spots is a critical aspect of a functional SERS device. The exact deposition dynamics are largely governed by substrate wettability, which itself is determined by: nanostructure geometry, material properties, and post-fabrication treatment. For nanostructured surfaces, the most pertinent wetting states are the well documented Wenzel and Cassie-Baxter regimes. Precise control of these properties can yield vastly improved Raman signal enhancement. For example, hybrid-wetting surfaces exploit a wettability differential to trap molecules in hot-spot regions, and fully superhydrophobic surfaces reduce the substrate analyte contact area, thus, spatially confining said analyte after evaporation.
To our knowledge, this study is the first to investigate the interplay between nanostructure wettability and SERS enhancement for a complex biological analyte on laser induced periodic surface structures (LIPSS). LIPSS are fabricated and functionalized for use as SERS devices as described in our previous publication. EVs from a choriocarcinoma cell line (JEG-3) are then stained with Aco-600™ (Acoerela) fluorescent dye and deposited onto the substrate. A Nikon Eclipse 80i fluorescence microscope allows for ‘in-situ’ imaging of stained EVs on the LIPSS nanostructure. By correlating these images with contact angle measurements and other microscopy techniques, we aim at determining the relationship between LIPSS morphology, substrate wettability, and EV deposition location. It is hoped that these deposition mechanisms can then be correlated to the maximum achievable SERS enhancement of EVs. Ultimately, this investigation aims to improve reliability and reduce the detection limit of EVs using our nano-plasmonic sensor which is being developed as a non-invasive method for determining the health of human embryo during in-vitro fertilisation (IVF) treatment
| I am the presenting author | Yes |
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