Parallel fluorescence interrogation of multichannel chips for rapid point-of-care testing

The development of rapid and reliable point-of-care testing (POCT) devices requires optical platforms capable of combining fast readout, sensitivity, and robustness. In this work, a fully integrated optoelectronic platform for fluorescence detection in multichannel microfluidic chips is presented, based on a parallel optical interrogation strategy. The platform employs a diffractive optical element (DOE) to achieve simultaneous excitation of multiple microchannels and an array of waveguide absorption filters (WAFs) for parallel fluorescence collection and efficient rejection of excitation light. This configuration eliminates mechanical scanning and enables optical interrogation within a few seconds. The platform is integrated with a microfluidic handling system and dedicated control software, allowing automated execution of immunoassays. Stability and reproducibility were demonstrated through repeated chip loading experiments, showing low variability across microchannels. As a proof of concept, a fluorescence sandwich immunoassay for C-reactive protein (CRP) was implemented in plasma, achieving a limit of detection of 0.32 µg mL⁻¹ with good intra- and inter-chip reproducibility. The proposed approach demonstrates the potential of parallel optical architectures for the development of rapid, scalable, and reliable fluorescence-based POCT platforms.