Whole blood screening of antibodies using label-free nanoparticle biophotonic array platform

Abstract

A gold nanoparticle, localised plasmon array biosensor using light scattering has been employed in the detection of allergen-specific antibodies in whole blood and sera. The array sensor was functionalized with four different allergens, cat dander (Fel d1), dust mite (Der p1), peanut allergen (Ara h1) and dog dander (Can f1) and immuno-kinetic assay was performed to detect their respective anti-allergen IgG antibodies. Specific positive responses to antibodies at a concentration of 25 nM were observed for Fel d1, Der p1, and Ara h1 allergens, while the Can f1 channel served as a reference control. The sensitivity was further enhanced using a secondary anti-IgG detection antibodies to give a limit of detection of 2 nM. The results indicate the potential for nanoparticle scattering multiplexed arrays to screen unprepared blood samples at point-of-care for assays of complex samples such as the whole blood.

Label-free Fab and Fc affinity/avidity profiling of the antibody complex half-life for polyclonal and monoclonal efficacy screening

“…The active sensor surface is a set of nanoparticles with average radius 120 nm, and the assay kinetics is monitored in real time following the light scattered from each array element. Fbr is used as the reference channel and subtracted from the data to correct for changes in temperature, refractive index of the medium and the intensity field of the illuminating LED [24][25][26]14]. Examples for pAb (BSA)-BSA and pAb (CRP)-protein A/G are shown in Figs.…”

Accuracy and precision analysis for a biophotonic assay of C-reactive protein

“…The CRP assay was performed on an in-house immuno-kinetic assay platform using sensing light scattering from an array of bio-functionalised gold nanoparticles; Light Scattering Array Reader (LiScAR), a benchtop device described in detail elsewhere [13][14][15][26][27][28] . Briefly, ca.…”

“…The localised particle plasmon field has a penetration depth of 63 nm 16 , consequently the light scattering properties are sensitive to the refractive index local to the nanoparticle surface. The nanoparticles are functionalised with a self-assembled monolayer 13,28 to allow EDC-NHS coupling of biomolecules to the surface. The array is returned to the printer for functionalisation with the target assays: The immuno-kinetic assay is performed in three steps: (i) capture of the analyte from a diluted whole blood sample flowing over the surface; (ii) a running buffer wash step to remove the non-specifically bound material from the sensor surface; and (iii) an injection of detection antibody at fixed concentration, to complete a sandwich assay as shown in Figure 1.…”

“…A two-step sandwich assay provides sensitivity and specificity to the target analyte and video capture of the array spot brightness changes produces an immuno-kinetic assay with results in 8 minutes. The conversion to array reading technique into a technology requires the sensor platform to be robust in complex, biologically relevant media [11][12][13][14][15][16][17][18] with patient-topatient variability whilst preserving the accuracy and precision needed for regulatory approval and clinical diagnosis. Manufacture under regulatory control and subsequent production requires a set of quality control (QC) metrics defining the figures-of-merit of the assay that can be monitored during batch production.…”

Nanocomposite biosensors for point-of-care—evaluation of food quality and safety

“…Evaluations of IgE-based hypersensitivity due to peanut protein Ara h1 using AuNPs localized plasmon array have been studied up to a detection limit of 2 nM (Olkhov et al, 2012).…”