Plasmonics and Super-Hydrophobicity: A New Class of Nano-Bio-Devices

Early detection of diseases has great importance in terms of success of the disease treatment. In fact, it has a profound positive influence on the response provided by the patient, leading to shorter and less invasive treatment regimes. We consider here the Raman detection of low (atto-molar) concentrates of molecules by applying nanofabrication techniques in the fabrication of plasmonic devices fulfilling the requirement of superhydrophobicity. Plasmonic resonances will have the effect of substantially increasing the local electric field around the fabricated nano-device which, in turn, will positively affect the Raman signal. Similarly, the superhydrophobicity will play the crucial role in localizing the few molecules of the analyte around the plasmonic device, therefore allowing their detection in a manner otherwise impossible in diffusion-based devices. We will theoretically explain the concept of superhydrophobicity by providing also a roadmap for defining the optimal superhydrophobic device, then we will introduce the fabrication process to realize such a device and, finally, we will provide the Raman counting of a series of analytes together with electromagnetic simulations illustrating the role of the electric field in the formation of the Raman signal.