The application of the platform as a virus biosensor was successfully demonstrated by accurately quantifying MS2 bacteriophage, showing a calculated LOD of ~1.0 pfu/mL, lower than most previously published intact viral biosensors. of ~1.0 pfu/mL. Tuneable nanochannel geometries constructed directly on sensing electrodes offer label-free, sensitive, and cost-efficient point-of-care biosensing platforms that could be applied for a wide range of viruses. phage. The current intensity values were normalised as follows: = (is the normalised current difference between where is the mean concentration of the blank and is the standard deviation of the blank [9,28]. The silica deposited electrode shows a theoretical LOD of 37 nanoparticles/mL. Open in a separate window Figure 4 (A) Model viral particle (biotinylated gold nanoparticle) concentration response curves for the biosensors. All the markers represent the electrodes treated with silica glancing angle deposition (filled) and without silica deposition (hollow). The red Ivachtin circles show the results for the streptavidin-modified electrode incubated with biotinylated gold nanoparticles. The blue squares represent first control with an anti-goat IgG modified electrode incubated with biotinylated gold nanoparticles. The green triangles depict the second control with a streptavidin-modified electrode incubated with PEG-COOH coated gold nanoparticles. (B) MS2 bacteriophage concentration response curves for the biosensors where the red circles represent the biosensor modified with anti-MS2 antibodies; and the blue hollow circles represent the first control where the electrode was modified with anti-goat IgG. The green hollow squares show the second control where the electrode was modified with anti-MS2 antibody and incubated with (= 47 nm) makes MS2 an ideal analyte to demonstrate the potential to apply this biosensor to intact virus detection. The electrode was modified with anti-MS2 antibody which has a diameter of ~10 nm, somewhat larger than the diameter of streptavidin (~2 nm). We also used two controls: one where the electrode was modified with anti-goat IgG antibody, and the other Ivachtin where the anti-MS2 antibody-modified electrode was tested against phage, which has a similar size and morphology to MS2 [31]. As shown in Figure 4B, a gradual increase in normalised current intensity was observed in the biosensor with increasing virus concentration, while neither of the controls showed a significant change in the normalised current, indicating that this biosensor successfully detected MS2 bacteriophage in the PBS buffer. The biosensor calibration curve equation of y = 0.0187x + 0.0459 (R2 = 0.992) had a lower sensitivity compared to the biotinylated gold nanoparticle analyte with the silica coated PS spheres. This could be due to biofouling effect caused by some undesirable biomolecules including protein fragments of host bacteria that remained in the solution. The calculated theoretical LOD for the developed MS2 immunosensor is ~1.0 pfu/mL, which is lower than most of those reported previously, lower than the numbers observed in optical and electrochemical MS2 biosensors based on porous silicon transducers (6 pfu/mL9, 2 SH3RF1 107 pfu/mL [32], and 4.9 0.8 pfu/mL [33], respectively), and lower than the numbers observed in porous alumina membranes (~7 pfu/mL) [34], and in sandwich-based immunosensors incorporating carbon nanotubes (9.3 pfu/mL) [35]. Partial passivation, with silica deposition, may Ivachtin have contributed to a new lower LOD for virus detection, as confinement of viral particle recognition to the nanochannels alone is absent on previously reported nanochannel-based sensors. 4. Conclusions An innovative approach to detect whole viral particles with a nanochannel-based electrochemical biosensor was investigated with a monolayer of PS spheres directly assembled on a gold surface. A highly sensitive and selective immunosensor for intact virus detection has been fabricated using nanochannel architecture based on the negative space between close-packed PS spheres assembled on a gold electrode with the help of glancing angle deposition of silica on the top surface, confining viral recognition only within the channels. The spaces between the close-packed PS spheres were partially blocked upon the incubation of the biosensor with.