A compact and rapid aptasensor platform based on surface plasmon resonance

Abstract

Aptamers are synthetic single-stranded oligonucleotides which bind specifically to their target. They offer several advantages over antibodies. For example, aptamers can be produced under unphysiological conditions against almost any target, including toxic or pathological substances. They are also quicker and cheaper produced than antibodies, and are easy to modify without loss of activity. Furthermore, they exhibit high stability under a width range of conditions. Consequently, they make excellent receptors for the use in biosensors. This article describes the evaluation of a novel aptasensor based on the Surface Plasmon Resonance (SPR)-system developed by the Fraunhofer Institute for Applied Optics and Precision Engineering IOF (Jena, Germany) using a thrombin–aptamer interaction as a model system. The biotin-tagged aptamer was attached to the sensor's gold surface by means of its interaction with streptavidin. Thrombin solutions of different concentrations were pumped over this surface, and the interaction was measured under buffer flow. The binding signals for the thrombin–aptamer interaction were compared to those arising from a control random-oligonucleotide of the same size and bearing the same modifications. Using this approach, we were able to obtain reproducible, significant and stable signals with a limit of detection of about 26 nmol/L

Gating Hysteresis as an Indicator for Silicon Nanowire FET Biosensors

“…In particular, the previous fluorescence based bioanalytic assays have confirmed the binding of thrombin on TBA surfaces, prepared with identical functionalization approach [31]. Furthermore, the additional surface-regeneration step for this aptamer-target system aimed to separate the two biorecognition partners in an efficient manner [49,59] was implemented using NaOH in quartz crystal microbalance technique (QCM, Figure S2), and obtaining saturation levels after 270 nM thrombin, in agreement with previous findings [31] and other publications [60,61].This important step could be further integrated into the SiNW FET concept to increase the lifetime of the microchips by recycling.…”

“…A randomized control sequence (RDM, 3 -CATCCAACTGTCTCACAC-(CH 2 ) 6 -NH 2 -5 ) was immobilized on another NW FET as a nonspecific control test. After the removal of loosely attached strands, covalently bound DNA was incubated with 10 mM Tris buffer (pH 7.4) containing K + ions to promote the proper folding of the aptamer structure [48][49][50]. Further, 1 mM pure sodium phosphate buffer (SPB) buffer at pH 5.7 was injected into the channel prior to detection experiments to establish the reference baseline for further experiments.…”

Improving the sensitivity of optical biosensors by means of Bloch surface waves

“…It has been applied to different applications such as DNA hybridization [7] as well as protein sensing recently [8]. The optical system relies on disposable, injection moulded polymer chips and quasi monochromatic illumination.…”

BiotecVisions 2012, February

“…The platform is intended to be used as a low‐cost biosensor, which is robust, easy to transport, and demonstrates sensitive and label‐free detection of target molecules, such as peptides, proteins, nucleotides and whole virus particles. /ug [8]…”