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

Abstract

We report a flow-injection biosensor system with a capacitive transducer for assay and quality control of human immunoglobulin G (hIgG). The sensing platform is based on self-assembled monolayers (SAMs) of carboxylic acid terminated alkyl-thiols with covalently attached concanavalin A. The electrochemical characteristics of the sensor surface were assessed by cyclic voltammetry using a permeable redox couple (potassium ferricyanide). The developed biosensor proved capable of performing a sensitive label-free assay of hIgG with a detection limit of 1.0 microg mL(-1). The capacitance response depended linearly on hIgG concentration over the range from 5.0 to 100 microg mL(-1), in a logarithmic plot. Typical measurements were performed in 15 min and up to 18 successive assays were achieved without significant loss of sensitivity using a single electrode. In addition, the biosensor can detect hIgG aggregates with concentrations as low as 0.01% of the total hIgG content (5.0 microg mL(-1)). Hence, it represents a potential post-size-exclusion chromatography-UV (post-SEC-UV) binding assay for in-process quality control of hIgG, which cannot be detected by SEC-UV singly at concentrations below 0.3% of the total hIgG content.

Microcontact-BSA imprinted capacitive biosensor for real-time, sensitive and selective detection of BSA

“…Proper insulation of the electrode surface is an important step in the capacitive biosensor assay [40], [41], [42], [43], [44], [45], [46], [47]. Cyclic voltammetry (CV) is the generally used method in the presence of a permeable redox couple to evaluate the degree of insulation of the electrode surface.…”

“…Capacitive biosensors are the electrochemical sensors that measure changes in the dielectric properties when an analyte interacts with a biorecognition element on the sensor surface, causing a decrease in the capacitance [36], [37], [38], [39], [40], [41]. Capacitive biosensors have been used for the detection of various analytes like antigens, antibodies, proteins and heavy metal ions [42], [43], [44], [45], [46], [47]. These types of biosensors have a lot of advantages like inherent rapidity, high sensitivity, simplicity, low cost, easy manipulation and real-time measurement without labeling.…”

A novel competitive capacitive glucose biosensor based on concanavalin A-labeled nanogold colloids assembled on a polytyramine-modified gold electrode

“…They are particularly sensitive electrochemical tools, which have been employed extensively for various applications, including antibodybased detection of proteins and polysaccharides [24,25]. Recently, we introduced a new concept, using the capacitive biosensor to quantitatively study low molecular weight analytes in a competitive manner [26]. It is generally accepted that small molecules introduced to the capacitive transducer per se are not able to increase the thickness of the dielectric layer in order to induce a measurable signal.…”

HIV Diagnostics: Challenges and Opportunities

“…These sensors are able to detect various biotargets of interest [133][134][135][136], and sensitivities in the subattomolar range were demonstrated [137]. Also in commercial development are sensors that recognize antibody-antigen binding and DNA hybridization using surface plasmon resonance [33].…”