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A low-cost integrated biosensing platform based on SiN nanophotonics for biomarker detection in urine

Martens, D., Ramirez-Priego, P., Murib, M. S., Elamin, A. A., Gonzalez-Guerrero, A. B., Stehr, M., Jonas, F., Anton, B., Hlawatsch, N., Soetaert, P., Vos, R., Stassen, A., Severi, S., Van Roy, W., Bockstaele, R., Becker, H., Singh, M., Lechuga, L. M., Bienstman, P.
Analytical methods 2018 v.10 no.25 pp. 3066-3073
analytical methods, antigens, biomarkers, computer software, detectors, inflammation, instrumentation, interferometers, lab-on-a-chip technology, patients, point-of-care systems, polymers, prototypes, refractive index, silicon nitride, tuberculosis, urine
We present a low-cost integrated nanophotonic lab-on-a-chip platform suitable for point-of-care (POC) biomarker analysis. The sensor chip included in the platform contains multiplexed Mach–Zehnder interferometers with an on-chip optical spectral analyser consisting of an arrayed-waveguide grating. The sensor chip is fabricated in silicon nitride material, which makes it compatible with consumer-electronics-grade sources and detectors, leading to the possibility of low-cost instrumentation. The nanophotonic sensor chip exhibits a detection limit of 6 × 10⁻⁶ RIU (Refractive Index Units), which is in the same order of magnitude as the reported values for state-of-the-art evanescent wave sensors. The sensor chip is biofunctionalised with specific bioreceptors and integrated into a polymer microfluidic cartridge. The POC instrumentation platform contains optical excitation and read-out sub-systems and dedicated on-board software for real-time analysis of patient samples. To demonstrate the versatility of the platform, we present results both on the detection of an antigen related to tuberculosis directly in urine samples using a laboratory prototype and on the detection of a protein biomarker (CRP) related to inflammation using the integrated instrument.