Gqf100 50 7

Quartz capillaries (GQF100-50-7.5,
World Precision Instruments, U.K.) with an outer diameter of 1.0 mm
and an inner diameter of 0.5 mm with an inner filament were plasma-cleaned
(Harrick Plasma) and then pulled by a laser-based pipette puller (Sutter
Instrument, P-2000). Nanopipettes used in all nanopore experiments
were fabricated through a two-line protocol: (1) HEAT = 825, FIL =
4, VEL = 30, DEL = 130, PUL = 80 and (2) HEAT = 850, FIL = 3, VEL
= 20, DEL = 127, PUL = 185. It should be noted that these parameters
are instrumentally specific and were optimized to yield nanopore openings
of 12 ± 2 nm.

All the nanopipettes were fabricated by pulling quartz capillaries (GQF100-50-7.5, World Precision Instruments, UK) using a laser-assisted pipette puller (Sutter Instrument, P-2000, USA) as per protocol reported previously by our group^{33 (link),62 (link)}. Prior to pulling, the capillaries (inner diameter: 0.5 mm, outer diameter: 1.0 mm, length: 7.5 cm) were cleaned thoroughly for approximately 30 min using a plasma cleaner (Harrick Plasma) to remove any organic residues or contaminants on the quartz surface. A capillary was then set up on the capillary holder of the puller and pulled using an optimised two-line protocol: (1) HEAT: 775; FIL: 4; VEL: 30; DEL: 170; PUL: 80, (2) HEAT: 825; FIL: 3; VEL: 20; DEL: 145; PUL: 180. Nanopipettes generated using this protocol have pore size averaged at 22 ± 3 nm (n = 5), according to the SEM characterisation and conductance calculation, Supplementary Figs. 1 and 2. It is important to be aware that the pulling protocols are specific to the instrument and are very sensitive to environmental conditions such as humidity and temperature.