“…1 1/2-22 mm square coverslips (Corning Inc., Corning, New York, USA) were sonicated 30 minutes in the following solutions to make squeaky clean coverslips: hot tap water with Versa Clean detergent (Fisher Scientific, Hampton, New Hampshire, USA), hot tap water, distilled water, double distilled water, 1 mM EDTA solution (Fisher Scientific, Hampton, New Hampshire, USA), 70% ethanol in water and 100% ethanol. An adaptation of a protocol to functionalize coverslips with glutaraldehyde was used [40,41]. Cleaned coverslips were soaked in a 3:1 sulfuric acid (Fisher Scientific, Hampton, New Hampshire, USA):30% hydrogen peroxide (Fisher Scientific, Hampton, New Hampshire, USA) solution for one hour, washed with double distilled water and placed in 10 mL of 1% aminopropyltriethylsilane (APTES) (Fisher Scientific, Hampton, New Hampshire, USA) in 10 mM acetic acid for two hours.…”