Observations of Immuno-Gold Conjugates on Influenza Viruses Using Waveguide-Mode Sensors

Abstract

Gold nanoparticles were conjugated to an antibody (immuno-AuNP) against A/Udorn/307/1972 (H3N2) influenza virus to detect viruses on a sensing plate designed for an evanescent field-coupled waveguide-mode sensor. Experiments were conducted using human influenza A/H3N2 strains, and immuno-AuNP could detect 8×105 PFU/ml (40 pg/µl) intact A/Udorn/307/1972 and 120 pg/µl A/Brisbane/10/2007. Furthermore, increased signal magnitude was achieved in the presence of non-ionic detergent, as the virtual detection level was increased to 8×104 PFU/ml A/Udorn/307/1972. Immuno-AuNPs were then complexed with viruses to permit direct observation, and they formed a ring of confined nanodots on the membrane of both intact and detergent-treated viruses as directly visualized by scanning electron microscopy. With this complex the detection limit was improved further to 8×103 PFU/ml on anti-rabbit IgG immobilized sensing plate. These strategies introduce methods for observing trapped intact viruses on the sensing plates generated for optical systems.

Investigation on Optimally Performing Sensor Substrates through Bio-fouling of Immunoglobulin-Conjugated Gold Nanoparticles

“…Similar to the SEM analyses, UV-Vis-NIR spectrophotometry revealed hierarchical differences with regard to reflective changes following AuNP-IgG binding as Au Investigation on Optimally Performing Sensor Substrates Through Bio-fouling of Immunoglobulin… the suitability of SiO 2 for sensing applications and the requirement of anti-fouling agents when using Au as a substrate. These results are in agreement with previous reports of higher fouling on Au and Au-based nanostructures in various biosensing applications [5,8,34]. In this regard, AuNP-based colorimetric assays have been designed based on the non-specific attachment of nucleic acids and its dissociation upon binding with the target [35].…”

“…In this respect, there are various kinds of sensors and sensing substrates that are employed for the detection of biomolecules under optimized conditions [6][7][8][9]. Among these substrates, gold (Au) and silica (SiO 2 ) are commonly utilized for sensor development due to their biocompatibility [10][11][12][13][14][15][16][17][18][19][20][21][22].…”

“…Among available biological probes, special attention has been focused on the use of antibodies alone or conjugated with gold nanoparticles (AuNP) [8,31]. In this regard, immunoglobulin G (IgG) is routinely labelled with AuNP [7,31].…”

Gold Nanoparticles in Biosensing Analyses

“…To create an ideal biosensing configurations on AuNP, two potential biomolecules, namely aptamer and antibody as the probes are very commonly in use [10][11][12]26]. These molecules can be conjugated with AuNP through thiol-linker ( Fig.…”

“…Several different materials are also used to support AuNPs such as optical fibres, ITO glass, sol-gel matrix for the detection of human IgG [50], streptavidin [51], interleukin-1β [52] and propanethiol [53]. Similarly, waveguide-mode sensor, which mimic the principle of SPR, has been generated with higher sensitive sensing using AuNP conjugation for the detection of influenza viruses [10][11][12].…”