A fully Integrated Miniaturized Optical Biosensor for Fast and Multiplexing Plasmonic Detection of high- and Low-molecular Weight Analytes.

Optical biosensors based on plasmonic sensing schemes combine high sensitivity and selectivity with label-free detection. However, the use of bulky optical components is still hampering the possibility of obtaining miniaturized systems required for analysis in real settings. Here, we demonstrate a fully miniaturized optical biosensor prototype based on plasmonic detection that enables fast and multiplex sensing of analytes with high- and low-molecular weight (80 000 and 582 Dalton) as quality and safety parameters for milk: a protein (lactoferrin) and an antibiotic (streptomycin). The optical sensor is based on the smart integration of (i) miniatuirized organic optoelectronic devices used as light-emitting and -sensing elements and (ii) a functionalized nanostructured plasmonic grating for highly sensitive and specific localized surface plasmon resonance (SPR) detection. The sensor provides quantitative and linear response reaching a limit of detection of 10 -4 refractive index units once it is calibrated by standard solutions. Analyte-specific and rapid (15 minute-long) immunoassay-based detection was demonstrated for both targets. By using a custom algorithm based on principal-component analysis, a linear dose-response curve was constructed which correlated with a limit of detection (LOD) as low as 3.7 μg/mL for lactoferrin, thus assensing the miniaturized optical biosensor well-alined with the chosen reference benchtop SPR method. This article is protected by copyright. All rights reserved.