Detection of bioanalytes by a fluorescence-based innovative platform

A stand-alone platform was developed for the detection of bioanalytes for point of care applications. The heart of the platform is a polymethylmethacrylate (PMMA) multichannel chip which has immobilised the necessary chemistry for the implementation of the assay on its surface. The present chip is equipped with thirteen channel 10mm long, 500 μm wide and 50 μm high. A laser source emitting at 635 nm is used to scan all the microchannels. The selected wavelength depends on the label chosen in the immunoassays, which is the fluorophore DY647, characterised by absorption and emission peaks centred at 635 nm and 675 nm respectively. The anisotropic fluorescence emitted at the liquid/PMMA interface is preferably coupled to suitable optical waveguides embedded in the plastic chip. An optical fibre collects the fluorescence on the lateral side of the chip and send it to a photodetector. A fluidic system takes care to pump into the microchannels the proper solutions. Sandwich assay on sample serum were implemented for the determination of procalcitonin (PCT) and C-reactive protein (CRP). Limit of detections of 20 ng/mL and 10 ng/ml were achieved for PCT and CRP, respectively.