Para nitrophenol

Laminaribiose, cello-, xylo- and acetyl-chitooligosaccharides were obtained from Megazyme (Wicklow, Ireland). Sodium acetate, laminarin from Laminaria digitata, xylan from birch wood, para-nitrophenol and all para-nitrophenyl-β-d-glycosides were purchased from Sigma-Aldrich (St. Louis, Mo). All other chemicals were of molecular biology or analytical grades and purchsed from VWR International (Stockholm, Sweden).

Vinyltrichlorosilan (VTCS) was obtained from abcr GmbH (Karlsruhe, Germany) and stored under nitrogen.Coverslips of size 26 × 76 mm were purchased from Menzel (Braunschweig, Germany) and para-aminophenol, para-nitrophenol and sodium borohydride were obtained from Sigma-Aldrich (St.Louis, MO, USA) and used as received. The holes in the glass slides were drilled using a KL450 ultrasonic drill (AQUARUS, Pappenheim, Germany). Sputtering targets (Mo, Pt, Ni, Cu, Au) were obtained from BALTIC Preparation e.K (Wetter, Germany). Sputtering was conducted with a CCU-010 HV coating unit (Safematic, Zizers, Switzerland). BLAUBRAND^® intraMARK (Brandt GMBH, Wertheim, Germany) 5 µL capillaries were purchased from the University of Zurich supply shop. An IPC high-precision multichannel dispenser (ISM930C) was used as peristaltic pump (Ismatec, Wertheim, Germany). Double distilled water was from a glass double distillery apparatus (GFL, Burgwedel, Germany) and was used to treat the slides prior to coating (SNFs, bagels); all other solutions were prepared from ultrapure water (Simplicity^® UV system) (Millipore, Billerica, MA, USA). SEM images were taken on a 450 Zeiss Gemini (Zeiss, Jena, Germany). TEM was performed using a FEI Tecnai G2 Spirit (FEI company, Hillsboro, OR, USA).

Zinc acetate dihydrate (Zn(CH₃CO₂)₂·2H₂O), Ammonium hydroxide (NH₄OH), graphite powder, potassium permanganate (KMnO₄), sulfuric acid (98% H₂SO₄), hydrogen peroxide solution (H₂O₂), sodium borohydride (NaBH₄), dilute hydrochloric acid (5% HCl), ethanol, para-nitrophenol (PNP) were obtained from Sigma Aldrich (now Merck Life Sciences, UK) and used without further purification. Deionized water (DI) was used throughout the experiments.