Electrochemical signal amplification for immunosensor based on 3D interdigitated array electrodes.
Anal Chem
; 86(12): 5991-8, 2014 Jun 17.
Article
em En
| MEDLINE
| ID: mdl-24842332
ABSTRACT
We devised an electrochemical redox cycling based on three-dimensional interdigitated array (3D IDA) electrodes for signal amplification to enhance the sensitivity of chip-based immunosensors. The 3D IDA consists of two closely spaced parallel indium tin oxide (ITO) electrodes that are positioned not only on the bottom but also the ceiling, facing each other along a microfluidic channel. We investigated the signal intensities from various geometric configurations Open-2D IDA, Closed-2D IDA, and 3D IDA through electrochemical experiments and finite-element simulations. The 3D IDA among the four different systems exhibited the greatest signal amplification resulting from efficient redox cycling of electroactive species confined in the microchannel so that the faradaic current was augmented by a factor of â¼100. We exploited the enhanced sensitivity of the 3D IDA to build up a chronocoulometric immunosensing platform based on the sandwich enzyme-linked immunosorbent assay (ELISA) protocol. The mouse IgGs on the 3D IDA showed much lower detection limits than on the Closed-2D IDA. The detection limit for mouse IgG measured using the 3D IDA was â¼10 fg/mL, while it was â¼100 fg/mL for the Closed-2D IDA. Moreover, the proposed immunosensor system with the 3D IDA successfully worked for clinical analysis as shown by the sensitive detection of cardiac troponin I in human serum down to 100 fg/mL.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Imunoensaio
/
Técnicas Biossensoriais
/
Eletrodos
Tipo de estudo:
Guideline
Idioma:
En
Revista:
Anal Chem
Ano de publicação:
2014
Tipo de documento:
Article