2.1. Chemicals

Liquid detergent Decon 90 (Decon Laboratories™ Decon 90™) was provided by Fisher Scientific (Göteborg, Sweden). Sodium chloride (NaCl, purity 99.5%), sodium phosphate monobasic and dibasic (purity 99.0%) and ethylenediaminetetraacetic acid (purity 99.0%) were provided by Sigma-Aldrich (St. Louis, MO, USA), while trans 1, 2-bis-(4-pyridyl)-ethene (BPE) was purchased from Sigma-Aldrich (Schnelldorf, Germany). Other chemicals were of analytical grade purity. Squared glass coverslips were provided by Carl Roth GmbH +Co. KG, (Karlsruhe, Germany).

In the preparation of saline buffers and cleaning of coverslips, ultrapure distilled water (18.2 MΩ·cm) was used, here named dd-water and produced by a Millipore Milli-Q water purification system (Molsheim, France).