Microchannel chips for the multiplexed analysis of human immunoglobulin G–antibody interactions by surface plasmon resonance imaging

Abstract

We report the multiplexed, simultaneous analysis of antigen-antibody interactions that involve human immunoglobulin G (IgG) on a gold substrate by the surface plasmon resonance imaging method. A multichannel, microfluidic chip was fabricated from poly(dimethylsiloxane) (PDMS) to selectively functionalize the surface and deliver the analyte solutions. The sensing interface was constructed using avidin as a linker layer between the surface-bound biotinylated bovine serum albumin and biotinylated anti-human IgG antibodies. Four mouse anti-human IgG antibodies were selected for evaluation and the screening was achieved by simultaneously monitoring protein-protein interactions under identical conditions. Antibody-antigen binding affinities towards human immunoglobulin were quantitatively compared by employing Langmuir adsorption isotherms for the analysis of SPRi responses obtained under equilibrium conditions. We were able to identify two IgG samples with higher affinities towards the target, and the determined binding kinetics falls within the typical range of values reported in the literature. Direct measurement of proteins in serum samples by SPR imaging was achieved by developing methods to minimize nonspecific adsorption onto the avidin-functionalized surface, and a limit of detection (LOD) of 6.7 nM IgG was obtained for the treated serum samples. The combination of SPR imaging and multichannel PDMS chips offers convenience and flexibility for sensitive and label-free measurement of protein-protein interactions in complex conditions and enables high-throughput screening of pharmaceutically significant molecules.

A multipurpose capacitive biosensor for assay and quality control of human immunoglobulin G

“…Biosensors have attracted wide-spread attention in recent years for many reasons such as simple instrumentation, fast operation, and high sensitivity and selectivity. In parallel, several biosensors have been developed for measurement of hIgG, including piezoelectric (Chen et al, 2007;Li et al, 2003;Liu et al, 2003;Lu et al, 2000) and piezomagnetic biosensors (Ogi et al, 2006), surface plasmon resonance biosensors (Dong et al, 2008;Suzuki et al, 2002), and electrochemical biosensors such as amperometric biosensors (Bian et al, 2005;Dutra et al, 2000;Messina et al, 2005;Wilson and Nie, 2006), potentiometric biosensors (Li and Gao, 2008), and field-effect transistors (Cid et al, 2008;Kim et al, 2008). Furthermore, several online immuno-monitoring systems were successfully developed for the measurement of hIgG based on turbidimetric assays (Fenge et al, 1991;Middendorf et al, 1993), and fluorescence measurements (Reif et al, 1994).…”

Antibody immobilization on to polystyrene substrate—on-chip immunoassay for horse IgG based on fluorescence

“…The value of detection limit obtained from our system for horse IgG as a model analyte is comparable to that of some reported microfluidic systems. The present detection limit is found to be lower than that of a multiplexed microfluidic immunoassay system for human IgG (1 μg/ml) based on avidin-biotin bridge for antibody immobilization on to poly(dimethylsiloxane) by surface plasmon resonance imaging (Dong et al 2008) and a microfluidic system integrated with two-dimensional surface plasmon resonance phase imaging system for rabbit IgG (0.1 μg/ml) based on covalently immobilized antibody on to a SAM on gold (Lee et al 2007). Furthermore, the present detection limit is found to be higher than those of previously reported microfluidic systems, for instance, the obtained detection limit is higher than that of a polydimethylsiloxane microfluidic immunoassay system for sheep IgG (15 ng/ml) might be due to the fact that they used different detection strategies where enzyme tracers were involved (Eteshola and Leckband 2001) and that of a screen-printed microfluidic electrochemical immunoassay for mouse IgG (10 ng/ml) might be due to the different set up and detection strategy (Dong et al 2007).…”

A Sensitive and Disposable Graphene Oxide Electrochemical Immunosensor for Label-free Detection of Human Immunoglobulin G

“…5 Recently, IgG has been markedly realized as a potential biomarker for several types of diseases, including cancers, 6 Alzheimer's disease, 7 inflammatory bowel disease, 8 and autoimmune disease. 9 Resulting from the crucial role played by IgG as well as the sensitivity and selectivity resulting from the high affinity binding of the Ig to the antigen, significant efforts have been put into developing immunoassays for IgG detection, such as radioimmunoassay, enzyme-linked immunosorbent assay (ELISA), 10 chemiluminescence immunoassays, 11 surface plasmon resonance (SPR), 12 and label-free immunoassay based on an organic field-effect transistor. 13 However, these methods are time-consuming, expensive and require highly trained persons to operate.…”