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 27 min, which can hopefully widen the
detection window for Zika viremia and is therefore promising in worldwide Zika fever control.