Surface virus detection

The possibility to use the YI sensor for virus detection was explored by monitoring the interaction between a-HSV-1 gG antibody and HSV-1 virus particles. To this end, channel 1 was coated with protein pA as described in Sect. 10.4.2 followed by the immobilization of a a-HSV-1 gG layer on the sensing surface of channel 1. Channel 4 was used as a reference channel. Finally a solution with HSV-1 virus particles at a concentration of 105 particles/ml was added to channel 1. Figure 10.2 shows the phase change measured between channel 1 and reference channel 4, clearly demonstrating the detection of virus particles by the YI sensor (Fig. 10.15). 

Fig. 10.15 Virus detection test. Sensor signal (phase change) measured between channel 1 and the reference channel for the immobilization of anti HSV 1 glycoprotein G monoclonal antibody layer on the sensing surface of channel 1 (A HSV i gG) and the binding of HSV 1 particles to this layer (A IISV i). Reprinted from Ref. 28 with permission. 2008 American Chemical Society...

This diverse set of biosensing experimental demonstrations illustrates the flexibility of the OFRR device. Nearly any biomolecular recognition event can be detected. The examples illustrated with the previously described experiments include DNA sequence detection and virus detection through surface proteins. Additional biosensing examples for which the OFRR is well-suited include site-specific cleavage, protein-protein interactions, and cell genotype/phenotype identification through receptors. Furthermore, as shown by the theory outlined above, the OFRR can be accurately and precisely quantitative. 

Fig. 10 Herpes simplex virus detection. Validation for specific detection of herpes simplex virus using REVS a 500000 HSV (gD+) virions incubated on a surface coated with an HSV receptor (anti-gD monoclonal antibody), b the same number of HSV virions on a surface with a receptor to which HSV does not bind (control bovine IgG), c genetically modified HSV (gD ) on HSV receptor surface, d HSV on a soluble gD-blocked HSV receptor surface, e HSV in blocking solution (anti-gD monoclonal antibody) on HSV receptor surface. The traces have been displaced from zero on the y-axis for clarity...

As an example of the use of antibodies labeled with alkaline phosphatase for detection of in situ hybridization, an infection with BNYVV virus in sugar beet is shown in Fig. 3C. Lectins labeled with an avidin-biotin fluorescein conjugate was used to visualize a-galactosyl groups on the surface of S. pombe in Fig. 3D. 

The detection of flu viruses via a fluorescent sandwich immunoassay was reported by Bucher.(10) However, the method sensitivity was too low for direct detection of the virus. A novel sandwich immunoassay was described by Ogcr((lff7 for the detection of Botulinum Toxin A. Antibodies specific for Clostridium botulinum were covalently attached to the surface of a tapered fiber. After the capture of the antigen, a sandwich was formed with a rhodamine-labeled anti-toxin IgG, and the evanescent wave was measured. The assay was highly specific with detection limits near 5 ppb. 

The first spike proteins can be detected at the cell surface about 2 hours after infection (Birdwell and Strauss, 1974 K riainen et al., 1980). It takes about 1 hour more before mature viral particles are released extracellularly. The virus is released from the cell by a budding outward of the cell membrane. In this process the nucleocapsid binds to the plasma membrane which wraps around the nucleocapsid and the bud is expelled from the cell (Acheson and Tamm, 1967). 

Polythiophenes functionalized with monosaccharides have been evaluated for their ability to detect the influenza virus and E. coli (Baek et al. 2000). Copolymers of thiophene acetic acid 10 and carbohydrate-modified thiophenes 11 have been prepared via iron(III) chloride mediated polymerization. Addition of influenza virus to a sialic acid containing copolymer resulted in a blue shift of the polymer absorption maximum, resulting in an orange to red chromatic transition. Mannose-containing polythiophenes underwent color changes upon the addition of the lectin ConA or E. coli cells that contain cell surface mannose-binding receptors. A similar biotinylated pol5hhiophene afforded a streptavidin responsive material (Paid and Leclerc 1996). 

Enzyme activity on the surface of influenza virus was first detected by Hirst [23], who observed that red blood cells once agglutinated by influenza virus... 

Microcantilevers can be coated with DNA or antibodies to respond to biological molecules or even a single virus.1-2-3 Bound material can be detected by the change in resonant frequency, as above, or by measuring nanometer-scale static bending, shown at the left, caused by stress on the surface of the cantilever when molecules bind. 

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