A plasmonic biosensor based on light-diffusing fibers functionalized with molecularly imprinted nanoparticles for ultralow sensing of proteins

Plasmonic bio/chemical sensing based on optical fibers combined with molecularly imprinted nanoparticles (nanoMIPs), which are polymeric receptors prepared by a template assisted synthesis, has been demonstrated as a powerful method to attain ultra-low detection limits, particularly when exploiting soft nanoMIPs, that are known to deform upon analyte binding [1]. This work, presents the development of a surface plasmon resonance (SPR) sensor in silica light-diffusing fibers (LDFs) functionalized with a specific nanoMIP receptor, entailed for the recognition of the protein human serum transferrin (HTR). Despite their great versatility, to date LDF-SPR were just reported functionalized with antibodies. Here, the innovative combination of a SPR-LDF platform and nanoMIPs led to the development of a sensor with an ultra-low limit of detection (LOD), equal to about 4 fM, and selective for its target analyte HTR. Worth to note, the SPR-LDF-nanoMIP sensor was mounted within a specially designed 3D-printed holder yielding to a measurement cell suitable for a rapid and reliable setup, easy for the scaling up of the measurements. [2]