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Because of the serological cross-reactivity among the flaviviruses, molecular detection methods, such as reverse-transcription polymerase chain reaction (RT-PCR), play an important role in the recent Zika outbreak. However, due to the limited sensitivity, the detection window of RT-PCR for Zika viremia is only about one week after symptom onset. By combining loop-mediated isothermal amplification (LAMP) and AC susceptometry, we demonstrate a rapid and homogeneous detection system for the Zika virus oligonucleotide. Streptavidin-magnetic nanoparticles (streptavidin-MNPs) are premixed with LAMP reagents including the analyte and biotinylated primers, and their hydrodynamic volumes are dramatically increased after a successful LAMP reaction. Analyzed by a portable AC susceptometer, the changes of the hydrodynamic volume are probed as Brownian relaxation frequency shifts, which can be used to quantify the Zika virus oligonucleotide. The proposed detection system can recognize 1 aM synthetic Zika virus oligonucleotide in 20% serum with a total assay time of 27min, which can hopefully widen the detection window for Zika viremia and is therefore promising in worldwide Zika fever control., (Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.)

Simultaneous detection of Salmonella enterica, Listeria monocytogenes and Escherichia coli based on triple-tagging multiplex PCR and electrochemical magneto genosensing on silica magnetic particles is reported. A set of tagging primers were selected for the specific amplification of yfiR (375 bp), hlyA (234 bp) and eaeA (151bp), being one of the primers for each set labelled with fluorescein, biotin and digoxigenin coding for S. enterica, L. monocytogenes and E. coli, respectively. Afterwards, electrochemical magneto genosensing of the bacteria was achieved by using silica magnetic particles as a carrier and three different electrochemical reporters, specific for each pathogen. This method was able to clearly distinguish among the pathogenic bacteria tested within 50 min, with detection limits ranging from 12 to 46 pg μL(-1)., (Copyright © 2015 Elsevier B.V. All rights reserved.)

We present novel solutions to surpass current analytic limitations of Magneto-Optical Surface Plasmon Resonance (MOSPR) assays, concerning both the chip structure and the method for data analysis. The structure of the chip is modified to contain a thin layer of Co-Au alloy instead of successive layers of homogeneous metals, as currently used. This alloy presents improved plasmonic and magnetic properties, yet a structural stability similar to Au-SPR chips, allowing for bioaffinity assays in saline solutions. Analyzing the whole reflectivity curve at multiple angles of incidence instead of the reflectivity value at a single incidence angle provides a high signal-to-noise ratio suitable for detection of minute analyte concentrations. Based on assessment of solutions with known refractive indices as well as of a model biomolecular interaction (i.e. IgG-AntiIgG) we demonstrate that the proposed structure of the MOSPR sensing chip and the procedure of data analysis allows for long-time assessment in liquid media with increased sensitivity over standard SPR analyses., (Copyright © 2014 Elsevier B.V. All rights reserved.)