Surface enhanced Raman scattering (SERS) is a powerful biosensing technique allowing direct detection of target molecules thanks to their vibrational fingerprint Raman spectra. SERS is usually performed on nano roughened plamonic planar substrates/colloidal nanoparticles. However, the irregularities of plasmonic nanostructures lead to measurement reliability limitations. We have recently demonstrated that SERS-probes based on opto-fluidic photonic crystal fiber (PCF) composed of a silica-core surrounded by large air channels are remarkable sensing platforms leading to tremendous SERS sensitivity and excellent measurement reliability (98% in reproducibility and 95% in repeatability). However, a major limitation occurs when looking for highly reliable and easy-to-use biosensing platform. Actual SERS biosensors (planar substrate or fiber probe) require their alignment under a microscope, which could restrict on-field practical use. Here, we address this issue by developing a tapered opto-fluidic PCF allowing excellent reliability, efficient and easy coupling through a Plug-&-Play type modality. This novel type of SERS probe realized by reducing the fiber diameter, which increases the SERS sensitivity while enabling efficient light coupling to the Raman spectrometer with a relative standard deviation (RSD) of only 3.5% in reproducibility and 3.84% in repeatability. We demonstrate this easy Plug-&-Play type coupling based on a simple bare fiber connector, with a RSD of 4.5% in reproducibility measurements (i.e. removing and reconnecting the fiber SERS-probe to the Raman spectrometer without any additional alignment). We envision that this easy-to-use platform can be translated to - clinically viable SERS probes for liquid biopsy.
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