A monolithic silicon optoelectronic transducer as a real-time affinity biosensor.
An optical real-time affinity biosensor, which is based on a monolithic silicon optoelectronic transducer and a microfluidic module, is described. The transducer monolithically integrates silicon avalanche diodes as light sources, silicon nitride optical fibers, and p/n junction detectors and efficiently intercouples these elements through a self-alignment technique. The transducer surface is hydrophilized by oxygen plasma treatment, silanized with (3-aminopropyl)triethoxysilane and bioactivated through adsorption of the biomolecular probes. The use of a microfluidic module allows real-time monitoring of the binding reaction of the gold nanoparticle-labeled analytes with the immobilized probes. Their binding within the evanescent field at the surface of the optical fiber causes attenuated total reflection of the waveguided modes and reduction of the detector photocurrent. The biotin-streptavidin model assay was used for the evaluation of the analytical potentials of the device developed. Detection limits of 3.8 and 13 pM in terms of gold nanoparticle-labeled streptavidin were achieved for continuous- and stopped-flow assay modes, respectively. The detection sensitivity was improved by silver plating of the immobilized gold nanoparticles, and a detection limit of 20 fM was obtained after 20-min of silver plating. In addition, two different analytes, streptavidin and anti-mouse IgG, were simultaneously assayed on the same chip demonstrating the multianalyte potential of the sensor developed.
Misiakos
Konstantinos
K
Microelectronics Institute, NCSR Demokritos, 15310, Aghia Paraskevi, Attiki, Greece. misiakos@imel.demokritos.gr
Kakabakos
Sotirios E
SE
Petrou
Panagiota S
PS
Ruf
Hans H
HH
D000327:Adsorption; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D001710:Biotin; D002417:Cattle; D004867:Equipment Design; D006046:Gold; D036103:Nanotechnology / Q000295:instrumentation; D055095:Optics and Photonics; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000032:analysis; D012825:Silicon; D012834:Silver; D019809:Streptavidin; D013997:Time Factors; D014159:Transducers
D012710:Serum Albumin, Bovine; D012834:Silver; D001710:Biotin; D006046:Gold; D019809:Streptavidin; D012825:Silicon