The Development and Standardization of a U-Bent LSPR Fiber Optic Biosensor to Screen for Parvovirus B19 IgM ^†

Introduction. Nearly 50% of the adult population has been exposed to parvovirus B19 (B19V). B19V has an elevated risk of transmission through blood and blood products as it is resistant to common inactivation procedures. Multiple studies have documented high IgM seroprevalence among blood donors that were recently exposed to B19V, which could pose a risk to blood safety programs. This study aimed to develop a lateral surface plasmon resonance (LSPR) U-Bent fiber optic biosensor (fob) that could screen B19V IgM.

Methods. A linear epitope against B19V was identified using Bepipred2.0 and commercially synthesized. The epitope was validated using ELISA against synthetic IgM control and then was tested against clinical B19V IgM samples. A label-free method was employed to mount the biotinylated epitope on the LSPR fob and then test the absorbance against B19V IgM. A bump in the spectral absorbance curve indicated that the sample was positive for B19V IgM. The fob was calibrated at each step, measuring the pre- and post-wash absorbance reading to accommodate the different buffers.

Results. The epitope demonstrated suitable reactivity against B19V IgM as demonstrated by ELISA. The label-free method was suitable in the identification of low levels of a synthetic B19V antibody with similar detection indices to B19V ELISA.

Discussion. Individuals who screen as B19V IgM-positive (that indicates recent infection) can then be screened for B19V DNA. The transfusion of B19V DNA-positive blood and blood products can lead to severe consequences for individuals who are hematologically stressed or immunocompromised. Multiple studies have documented the importance of screening for B19V especially among blood donors by the introduction of routine screening into their national blood safety programs. A sensitive and specific rapid test such as this LSPR fob would be very beneficial in the B19V screening.