Research Highlights

MPS for the Detection of Influenza A Virus H1N1

In our ACS AMI paper, we have successfully demonstrated the feasibility of using a MPS system combined with the self-assembly of MNPs for rapid, sensitive, and wash-free detection of H1N1 virus.

The H1N1 nucleoprotein molecule has multiple epitopes that serve as binding sites for IgG polyclonal antibodies. Thus, each H1N1 nucleoprotein may be bound to more than one MNP, consequently assembling into clusters. In addition, each MNP functionalized with IgG antibodies specific to multiple epitopes of the H1N1 nucleoprotein enabling the particle to bind to multiple H1N1 nucleoprotein molecules. As a result, the cross-linking of MNPs and H1N1 nucleoproteins leads to different degrees of MNP self-assemblies depending on the number/concentration of H1N1 nucleoprotein molecules in the MNP ferrofluid.

Noticeable changes in the macroscopic magnetic responses of MNPs are detected by the MPS system when these ferrofluid samples are subjected to external oscillating magnetic fields. Herein, we have reported the 3rd harmonic, the 5th harmonic, and the harmonic ratio R35 as metrics for the detection of H1N1 nucleoprotein.

MPS for Blood Viscosity Measurement

In our APL paper, we proposed and demonstrated a Brownian relaxation-based method to test human serum viscosity. This method uses Brownian relaxation-dominated superparamagnetic nanoparticles, which are sensitive to variables of the liquid environment such as viscosity and temperature.

(Top) The real-time voltage signal of the 3rd harmonic for MNPs from nine mixtures of varying viscosities measured at 20 C. (Bottom) The 3rd harmonic amplitude drop in percentage vs. viscosity.

In this work, we proposed and demonstrated the feasibility of using a MPS system to test human serum viscosity in real-time. Glycerol and DI water mixtures were used to simulate in vitro viscosity test processes. It was found that the measurement of the voltage change percentage of the 3rd harmonic works well for the in vitro viscosity test. We tested and plotted the standard graphs that could be used to estimate the viscosity of any unknown liquids. We also tested the viscosity of a male human serum type AB by inserting the collected data into standard graphs. The estimated viscosity of this serum is 2.2 cp at 40 C and 1.8 cp at 20 C, compared to the real value of 1.35 cp and 1.74 cp, respectively.