Ferritin immunosensing on microfabricated electrodes based on the integration of immunoprecipitation and electrochemical signaling reactions.
A signal registration strategy from micropatterned immunosensors that converts antigen-antibody binding reactions into electrochemical signals was demonstrated. An array-type micropatterned gold electrode on a silicon wafer was fabricated, containing two electrode geometries of rectangular (100 microm x 500 microm) and circular (r. 50 microm) types, exhibiting electrochemical characteristics of bulk and micro-electrodes, respectively. Ferritin was employed as a model analyte for immunosensing because it has an advantageous molecular structure for functionalization to the sensing interface, and is regarded as a general marker protein for tumors and cancer recurrence. With the fabricated and ferritin-functionalized immunosensors, biospecific interactions were performed with antiferritin antiserum and secondary antibody samples, followed by electrochemical signaling via an immunoprecipitation reaction by the label enzyme. Under the optimized affinity-surface construction steps and reaction conditions, both types of microfabricated electrodes exhibited well-defined calibration results as a function of the protein concentration in antiserum samples. Furthermore, circular-type micropatterned immunoelectrodes exhibited voltammetric characteristics of microelectrodes, which is advantageous in terms of sensor operation under a fixed potential and low signal drift during the signaling reaction compared with the bulk-type electrodes. The results support that the employed signaling method with the proposed immunosensor configuration is fit for sensor miniaturization and integration to future biomicrosystems.
Yoon
Hyun C
HC
Department of Biotechnology, Ajou University, Suwon 442749, Korea. hcyoon@ajou.ac.kr
Yang
Haesik
H
Byun
Sang Yo
SY
D000937:Antigen-Antibody Reactions; D015374:Biosensing Techniques; D004563:Electrochemistry; D005293:Ferritins / Q000032:analysis*; D006046:Gold; D047468:Immunoprecipitation / Q000295:instrumentation / Q000379:methods*; D008839:Microelectrodes
D006046:Gold; D005293:Ferritins