title: Protein-resistant self-assembled monolayers on gold with latent aldehyde functions.
abstract: In the present study, oligo(ethylene glycol) (OEG)-linked alkanethiols were synthesized which carry a vicinal diol on one end of the OEG chain. After self-assembled monolayer (SAM) formation on gold, the vicinal diols were converted into aldehyde functions by exposure to aqueous NaIO4, as previously used for SAMs with OEG chains buried in the center of the SAM [Jang et al. Nano Lett. 2003, 3, 691-694]. Mixed SAMs with latent aldehydes on 5% of the OEG termini showed high protein resistance, which greatly slowed the kinetics of protein coupling on the time scale of minutes. Small bioligands (such as biocytin hydrazide) or small heterobifunctional crosslinkers (maleimidopropionyl hydrazide, pyridyldithiopropionyl hydrazide) with hydrazide functions were efficiently bound to the aldehyde functions on the SAM, providing for specific capture of streptavidin or for fast covalent binding of proteins with free thiols or maleimide functions, respectively. In conclusion, OEG-terminated SAMs with latent aldehydes serve as protein-resistant sensor surfaces which are easily functionalized with small ligands or with heterobifunctional crosslinkers to which the bait molecule is attached in a subsequent step.
authors: Institute of Biophysics and Institute of Organic Chemistry, University of Linz, Altenberger Str. 69, A-4040 Linz, Austria.
authors: Martin
authors: M
authors: Hölzl
authors: Ali
authors: A
authors: Tinazli
authors: Christa
authors: C
authors: Leitner
authors: Christoph D
authors: CD
authors: Hahn
authors: Bernd
authors: B
authors: Lackner
authors: Robert
authors: R
authors: Tampé
authors: Hermann J
authors: HJ
authors: Gruber
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D015374:Biosensing Techniques; D003432:Cross-Linking Reagents / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D007700:Kinetics; D011092:Polyethylene Glycols / Q000737:chemistry*; D019809:Streptavidin / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D003432:Cross-Linking Reagents; D013438:Sulfhydryl Compounds; D011092:Polyethylene Glycols; D006046:Gold; D019809:Streptavidin