When small molecules are incorporated into self-assembled monolayers (SAMs) as targets for recognition by larger biomolecules, the tethers used to extend the targets from the surface can often interfere with the recognition process. Moreover, even at low loading, the surface molecules may not disperse but instead phase-separate into clusters, thus creating steric hindrance and increasing the chances of nonspecific binding. Shuster et al. present a strategy to overcome these drawbacks in a search to identify yet unknown binding partners for serotonin. First they prepared alkane thiol SAMs on gold that were terminated with oligomers of ethylene glycol. Carboxyl-terminated thiols with twice the number of ethylene glycol repeats were then bound to defect sites in the SAMs and covalently capped with serotonin. Quartz crystal microbalance studies showed that these monolayers preferentially bound serotonin antibodies over those raised against dopamine and were also resistant to binding of bovine serum albumin. -- PDS
Adv. Mater. 10.1002/adma.200700082 (2007).
