Selfassembled monolayers (SAMs) of chemisorbed thiols on gold play an important role as platforms for biosensors. Ordered SAMs and multilayers can also be prepared by noncovalent adsorption of amphiphiles. The pH controlled amphiphile adsorption- desorption is rapid, allowing repeated assembly-test-disassembly of the layer structure for regeneration of e.g. a sensor interface after use.  By introducing biologically active ligands such as biotin we have shown that a fully reversible biosensor platform can be achieved with this system with multiple tuning opportunities using one single substrate. The multilayer system was subsequently used for sensing applications e.g. detecting HSA using biotinylated anti-HSA or PSA using biotinylated anti-PSA. In both systems very low detection limits were achieved i.e. 70 pM for HSA and 40 fM for PSA, outperforming corresponding biosensors relying on irreversible chemisorbed SAMs.  The enhanced sensitivity we attribute to a more optimal packing and orientation of the proteins docked to the reversible sensor platform.

Ultrasensitive biosensors via reversible mixed SAMs

243rd National Meeting (2012)

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