Covalent biofunctionalization of silicon nitride surfaces

Langmuir. 2007 May 22;23(11):6233-44. doi: 10.1021/la7007045. Epub 2007 Apr 25.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Animals
  • Biosensing Techniques
  • Cattle
  • Coated Materials, Biocompatible / chemistry
  • In Vitro Techniques
  • Microscopy, Atomic Force
  • Oligopeptides / chemistry
  • Proteins / chemistry
  • Silicon Compounds / chemistry*
  • Spectrometry, Mass, Secondary Ion
  • Spectrum Analysis
  • Surface Properties
  • X-Rays


  • Coated Materials, Biocompatible
  • Oligopeptides
  • Proteins
  • Silicon Compounds
  • silicon nitride