Meo peg nhs

Cover slips and objective slides were cleaned by bath sonication in 1 M KOH and exposure to plasma (FEMTO plasma cleaner, Diener Electronic GmbH, Germany). Surfaces were then silanized by sonication in 3.9 mM N1-[3-(trimethoxysilyl) propyl] diethylenetriamine (Sigma-Aldrich) and 1.7 mM acetic acid, and baked for 20 min at 120 °C. PEG/PEG-Biotin functionalization of silanized surfaces was carried out by incubation with 20 mM PEG-NHS (MeO-PEG-NHS, IRIS Biotech GmbH, PEG1165), 0.2 mM Biotin-PEG-NHS (IRIS Biotech, PEG1057) and 20 mM KOH in 100 mM H₃BO₃ solution for 1 h at room temperature. Excess PEG was removed by 1 min sonication in H₂O. Cover slips were dried at 60 °C and stored under vacuum. For TIRF experiments, flow chambers were generated by combining objective slides and cover slips with double-sided sticky tape.

Coverslips and objective slides were sonicated in 1 M KOH for 10 min, cleaned in plasma cleaner (FEMTO plasma cleaner, Diener Electronic GmbH), silanized in 3.9 mM N1-[3-(trimethoxysilyl)propyl] diethylenetriamine (Sigma-Aldrich) and 1.7 mM acetic acid for 5 min and baked for 20 min at 110 °C. They were covered with 20 mM PEG-NHS (MeO-PEG-NHS, IRIS Biotech GmbH, PEG1165), 0.2 mM Biotin-PEG-NHS (IRIS Biotech GmbH, PEG1057) in 100 mM H₃BO₃ for 1 h at room temperature, washed with H₂O to remove excess of PEG, dried at 50 °C and stored under vacuum. Flow chambers were assembled by attaching cover slips on objective slides with double-sided sticky tape.