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.
Department of Biotechnology, Ajou University, Suwon 442749, Korea. hcyoon@ajou.ac.kr
Hyun C
HC
Yoon
Haesik
H
Yang
Sang Yo
SY
Byun
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