Covalent biofunctionalization of silicon nitride surfaces.
Covalently attached organic monolayers on etched silicon nitride (SixN4; x >/= 3) surfaces were prepared by reaction of SixN4-coated wafers with neat or solutions of 1-alkenes and 1-alkynes in refluxing mesitylene. The surface modification was monitored by measurement of the static water contact angle, XPS, IRRAS, AFM, and ToF-SIMS, and evidence for the formation of Si-C bonds is presented. The etching can be achieved by dilute HF solutions and yields both Si-H and N-H moieties. The resulting etched SixN4 surfaces are functionalized by terminal carboxylic acid groups in either of two ways: (a) via attachment of a 10-undecenoic acid 2,2,2-trifluoroethyl ester (trifluoro ethanol ester) and subsequent thermal acid hydrolysis; (b) through attachment of a photocleavable ester, and subsequent photochemical cleavage, as this would allow photopatterned functionalized SixN4. The carboxylic acids are successfully used for the attachment of oligopeptides (aspartame) and complete proteins using EDC/NHS chemistry. Finally, an amino-terminated organic monolayer can be formed by reaction of HF-treated SixN4 surfaces with a N-(omega-undecylenyl)phthalimide, which yields an amino-terminated surface upon deprotection with hydrazine.
Arafat
Ahmed
A
Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
Giesbers
Marcel
M
Rosso
Michel
M
Sudhölter
Ernst J R
EJ
Schroën
Karin
K
White
Richard G
RG
Yang
Li
L
Linford
Matthew R
MR
Zuilhof
Han
H
D000327:Adsorption; D000818:Animals; D015374:Biosensing Techniques; D002417:Cattle; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D066298:In Vitro Techniques; D018625:Microscopy, Atomic Force; D009842:Oligopeptides / Q000737:chemistry; D011506:Proteins / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry*; D018629:Spectrometry, Mass, Secondary Ion; D013057:Spectrum Analysis; D013499:Surface Properties; D014965:X-Rays
D020099:Coated Materials, Biocompatible; D009842:Oligopeptides; D011506:Proteins; D017655:Silicon Compounds; C032734:silicon nitride