Development of surface chemistry for surface plasmon resonance based sensors for the detection of proteins and DNA molecules

Abstract

The immobilisation of biological recognition elements onto a sensor chip surface is a crucial step for the construction of biosensors. While some of the optical biosensors utilise silicon dioxide as the sensor surface, most of the biosensor surfaces are coated with metals for transduction of the signal. Biological recognition elements such as proteins can be adsorbed spontaneously on metal or silicon dioxide substrates but this may denature the molecule and can result in either activity reduction or loss. Self assembled monolayers (SAMs) provide an effective method to protect the biological recognition elements from the sensor surface, thereby providing ligand immobilisation that enables the repeated binding and regeneration cycles to be performed without losing the immobilised ligand, as well as additionally helping to minimise non-specific adsorption. Therefore, in this study different surface chemistries were constructed on SPR sensor chips to investigate protein and DNA immobilisation on Au surfaces. A cysteamine surface and 1%, 10% and 100% mercaptoundecanoic acid (MUDA) coatings with or without dendrimer modification were utilised to construct the various sensor surfaces used in this investigation. A higher response was obtained for NeutrAvidin immobilisation on dendrimer modified surfaces compared to MUDA and cysteamine layers, however, protein or DNA capture responses on the immobilised NeutrAvidin did not show a similar higher response when dendrimer modified surfaces were used.

Surface Plasmon Resonance Immunosensor for the Detection of Campylobacter jejuni

“…A 1:1 mixture of 100 mM NHS and 400 mM EDC, prepared fresh in deionized water, was injected (3 min at a flow rate of 25 µL·min −1 ) across the sensor surfaces to activate the surface. The mixture converts the carboxylic terminal groups of self-assembled monolayer (SAM) into the active ester of NHS [16]. Immediately, the different concentrations of rabbit polyclonal antibody against C. jejuni (50, 70, 100 and 150 µg·mL −1 ) were injected (3 min at a flow rate of 25 µL·min −1 ) on the parallel spots to determine the optimum concentration of the surface antibody.…”

“…Chemosensors 2017, 5, 16 12 of 15 use of nanoparticles for the enhancement of SPR-based detection of bacteria. SPR-based detection of bacteria is limited by the short penetration depth of the evanescent wave.…”

Electrochemical Reduction Potential Shifts of Graphene Oxide Employed in Thrombin Detection

“…NH 2 -terminated TBA (NH 2 -C 6 -5'TTT TTT TTT TTT TTT AGT CCG TGG TTG GTG TGG TTG GGG TGA CT-3') was immobilized onto GO/PEI/MPA/Au through the covalent coupling reaction. 18,19 Thrombin may be captured by TBA through forming G-quadruplex structure, which changes a chemical circumstance of GO, resulting in the different electrochemical behavior of GO (Scheme 1).…”

Effects of Interfacial Properties of a Surface Modified Surface Plasmon Resonance Chip on Protein Immobilization Performance

“…5 SPR has attracted interest for biosensing [6][7][8] especially with respect to biomolecular interactions. [9][10][11] By contrast with other reported analytical methods such as immunofluorescence, 12,13 chromatographic analysis 14,15 and mass spectrometry, 16,17 which usually require expensive equipment and complicated operation, biosensors based on the SPR process offer many superior advantages, including but not limited to label-free and real-time detection, low sample consumption, less time-consuming process, high sensitivity and efficiency, and the strong capability of anti-electromagnetism. 18,19 Therefore, SPR sensing has been widely used in applications in different fields e.g., medical diagnostics, biopharmaceutical, environmental monitoring and food security.…”

“…24 The resulting layer on the SPR chip surface may minimize nonspecific adsorption of the chip and improve the sensitivity of SPR response by introducing the additional functionality of added terminal attaching groups for specific binding with target species. For example, Tothill et al 10 have reported the investigation of protein and DNA immobilization on Au surfaces by constructing different surface chemistries on SPR sensor chips. Results showed that the immobilization on the chip surface modified with self-assembled mercaptoundecanoic acid improved the sensitivity and produced the highest SPR response.…”