Invited Paper TF+BI-ThA8
Preparation and Characterization of Amino Coatings for Peptide Arrays

Thursday, November 10, 2016, 4:40 pm, Room 104E

Amine-functionalized substrates are among the most commonly used materials in solid-phase peptide synthesis. Chemical stability and amine loading of the amino coating are two important properties that determine silane selection as a building layer in peptide synthesis. We synthesized three different amino coatings i.e., APTES (3-aminopropyltriethoxysilane), APDEMS (3-aminopropyldiethoxymethylsilane) and APDIPES (3-aminopropyldiisopropylethoxysilane), and determined their strengths and limitations as a building layer in peptide array synthesis. Here, amino coatings were synthesized via gas-phase deposition of the corresponding silanes on thermal oxide-terminated silicon substrates in a commercial chemical vapor deposition system. A 16-mer peptide coating was then synthesized on the amino surfaces and the chemical stability of the surface to highly acidic side chain deprotection (SCD) treatments was determined. After SCD, the coating thicknesses decrease to different degrees on the surfaces: it is greatest for the APDIPES surface, lowest for the APTES surface and intermediate for the APDEMS surface, which indicates that peptide-functionalized APTES and APDIPES surfaces are chemically most and least stable to SCD treatment, respectively. The effect of amine loading on peptide density and purity was also determined for the three amino surfaces. Four different trimers were synthesized on the amino surfaces, and the density and purity of these trimers for the three surfaces was determined. A positive correlation between the amine loadings and peptide densities was observed; peptide density was highest for the APTES surface and lowest for the APDIPES surface. However, high amine loading is found to have a negative impact on peptide purity; peptide purity is highest for the APDIPES surface and lowest for APTES surface. Coated surfaces were characterized by spectroscopic ellipsometry, contact angle goniometry, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), spectrophotometry, and MALDI-MS.