Playing “Nano -Lego ”: VNPs as Building Blocks for the Construction of Multi -Dimensional Arrays - Viral Nanoparticles: Tools for Materials Science and Biomedicine - page 198

driven by low pH and results in release of the genomic information into the
cytoplasm. This mechanism has been utilized to trigger fusion of enveloped
VNPs with lipid membranes on solid supports and beads, where surface is
coated with a lipid bilayer followed by low-pH-catalyzed fusion. Systems
with stably immobilized Rubella VLPs and Influenza A/PR8 viruses

3

have

been developed (Fischlechner ., 2006).

Such virus-coated beads have been used as diagnostic tools for the
detection of virus-specific antibodies. To highlight an example,

et al ., 2006, 2007; Toellner et al

Rubella

VLPs or A/PR8 viruses were stably embedded onto beads coated

with lipid bilayers. First, the beads were coated with the polyelectrolytes
poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS).
Next, a lipid mixture of phosphatidylserine (PS) and phosphatidylcholine
(PC) was bound. When

Influenza

A/PR8 viruses were added
to these beads at low pH, the particles fused with the lipid bilayer and, as
a result, the VLPs were stably and firmly incorporated in the supported
membrane (Fischlechner

Rubella VLPs or Influenza

., 2007). To demonstrate the feasibility of such
VLP-coated beads in a diagnostic assay to detect virus-specific antibodies,
two different sets of beads were immobilized on a surface to create a
“sensor-on-a-chip” device. Microcontact printing was used to assemble
Rubella

et al

VLP-coated beads and Influenza A/PR8 virus-coated beads on a chip

(Fig. 7.22) (Fischlechner VLPs served as a negative

control and were labeled in green by fluorescent dye incorporation;
Influenza

et al ., 2007). Rubella

A/PR8 virus-coated beads were not color-coded. The device was
then exposed to polyclonal sera against A/PR8 virus. Detection

was carried out using phycoerythrin-labeled secondary antibodies (red)
(Fig. 7.22) (Fischlechner

Influenza

., 2007). Immunofluorescent imaging showed
high specificity, as indicated by the presence of very few yellow spots
(yellow spots result from an overlay of red and green fluorescence and are
false positive). The beads were further tested using flow cytometry; the
data were consistent, confirming high selectivity (Fischlechner

et al

., 2007).
The methods established could be applied to other pathogens and may lead
to the development of a range of devices for use in diagnostics.

et al

3

viruses are the infectious agents causing the disease influenza, commonly referred
to as the flu.

Influenza

Influenza viruses belong to the family Orthomyxoviridae , and affects birds and

mammals. The strain utilized is A/PR8 (H1N1), which has been isolated in Puerto Rico.

The virions have a complex structure and are enveloped. Virions are spherical to pleomorphic
and around 80-120 nm in diameter and 200-300 nm in length.

Influenza

A/PR8 (H1N1) has a
segmented genome consisting of eight segments of linear, negative-sense, single-stranded RNA
[from the Database of the International Committee on taxonomy on Viruses (ICTV; http://www.
ncbi.nlm.nih.gov/ICTVdb)].

Influenza