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

摘要

The immobilisation of biological recognition elements onto a sensor chip surfaceis a crucial step for the construction of biosensors. While some of the opticalbiosensors utilise silicon dioxide as the sensor surface, most of the biosensorsurfaces are coated with metals for transduction of the signal. Biologicalrecognition elements such as proteins can be adsorbed spontaneously on metal orsilicon dioxide substrates but this may denature the molecule and can result ineither activity reduction or loss. Self assembled monolayers (SAMs) provide aneffective method to protect the biological recognition elements from the sensorsurface, thereby providing ligand immobilisation that enables the repeatedbinding and regeneration cycles to be performed without losing the immobilisedligand, as well as additionally helping to minimise non-specific adsorption.Therefore, in this study different surface chemistries were constructed on SPRsensor chips to investigate protein and DNA immobilisation on Au surfaces. Acysteamine surface and 1%, 10% and 100% mercaptoundecanoic acid (MUDA) coatingswith or without dendrimer modification were utilised to construct the varioussensor surfaces used in this investigation. A higher response was obtained forNeutrAvidin immobilisation on dendrimer modified surfaces compared to MUDA andcysteamine layers, however, protein or DNA capture responses on the immobilisedNeutrAvidin did not show a similar higher response when dendrimer modifiedsurfaces were used.