SiM20 Posters

9 Sensors in Medicine 2020 Microfluidic paper device, depicted in Figure 2b, presents a first compartment for the incubation of MP-cAb/antigen/polyHRP-dAb with the fluorescent substrate, QuantaRed®. The mixture then flows towards a second cell, where a magnet retains the MB for in-chip detection. The microfluidic paper magneto-immunosensor displayed quadratic response between 0.78-25 ng mL -1 and LOD of 1.0 ng mL -1 , see Fig 4. Figure 4 a) Fluorescence signals and b) signal-to-noise ratios of Pf-LDH detection in diluted spiked PBS buffer by ELISA, classical approach and integrated single-step immunoassay into a µPDA. c) Pf-LDH detection in diluted spiked PBS buffer by µPDA. Standard 17 was the paper chosen whitin all different type of papers tested, because of its low autofluorescence. An integrated single-use microfluidic paper-based analytical device (µPDA) has been developed, capable to perform the incubation of the fluorescence substrate step and the tedious washing step, all into the paper. The developed device detected Pf-LDH in spiked PBS buffer in <15 min, providing an LOD of 1.0 ng mL -1 . The results show an enormous potential for paper microfluidics devices to be exploited to simplify magneto-immunoassay handling, taking MB closer to the requirements of POC testing. Acknowledgements. This work has been supported by grants (i) CPII18/00025, IFI18-00020 and DTS17/00145 (co-funded by Fondo de Investigaciones Sanitarias of the Instituto de Salud Carlos III, ISCIII, and the European Regional Development Fund, ERDF), (ii) 2017-SGR-908 (Generalitat de Catalunya) and (iii) KAA is supported by an INPhINIT fellowship (LCF/BQ/DI18/11660061) from ”La Caixa” Foundation (ID 100010434), with funding from European Union’s Horizon 2020 Marie Skłodowska Curie grant agreement No. 713673. Future Work. Fully integration of single-step magneto immunoassay directly into the microfluidic paper-based analytical device. Figure 3 a) Schematic process of the integrated device, where the incubation with the fluorescent substrate and the subsequent washing are performed directly into the device and b) Fluoresecent reader device. 3 Integrated incubation: - MB-cAb / PolyHRP-dAb / Antigen (Pf-LDH) - Fluorescent Substrate 5 min 4 Elution buffer and measure fluorescence Washing Remove unbound antigen and dAb 2 Single-step incubation: - MB-cAb - PolyHRP-dAb - Antigen (Pf-LDH) 5 min 1 =MB-cAb = PolyHRP-dAb = PF-LDH = QuantaRed 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 0.78 1.56 3.13 6.25 12.5 25 Signal-to-noise [Pf-LDH] ng mL-1 Integrated Microfluidic Device ELISA Classical Approach y = -59410x 2 + 523764x + 592978 R² = 0.8238 y = -76721x 2 + 684010x + 439808 R² = 0.7832 y = -50784x 2 + 431492x + 599608 R² = 0.9861 0 500000 1000000 1500000 2000000 2500000 0 1 2 3 4 5 6 7 Fluorescence Counts [Pf-LDH] ng mL -1 Integrated Microfluidic Device ELISA Classical Approach Results – Integrated single-step immunoassay into µPDA: Conclussions 0,0 0,78 1,6 3,1 6,3 12,5 25,0