Cells

The cell lines CHO-K1 (epithelial cells from Hamster ovary; kind gift by Dr. M. Zaccolo, Department of Physiology, Anatomy and Genetics, University of Oxford) and SH-SY5Y (from human neuroblastoma; kind gift by Dr. S. Guarnieri, Dipartimento di Scienze Mediche di Base ed Applicate, Università di Chieti-Pescara, Italy) were maintained in F-12 Nutrient Mixture—Ham—and DMEM media, respectively, both supplemented with 10% (v/v) heat-inactivated FBS (Foetal Bovine Serum), 10 u/ml penicillin and 10 μg/ml streptomycin, in a humidified atmosphere at constant temperature (37 °C) and CO₂ concentration (5% v/v). Two days before the electroporations, 2 × 10⁴ and 10⁴ cells/cm² were plated on chips for experiments with Trypan Blue and plasmids, respectively.

Wistar rats (Charles River) were maintained in the Animal Research Facility of the Department of Biomedical Sciences (University of Padua) under standard environmental conditions. All the procedures involving animals were realized according to Italian regulations for animal welfare (ethics approval from the Italian Ministry of Health, authorization number 522/2018-PR) and in compliance with the ARRIVE guidelines. Primary neurons were dissociated with papain from freshly dissected E18 rat embryos hippocampi as described previously⁴⁹. About 3 × 10⁴ neurons/cm² were plated on chips (pre-coated with 10 μg/ml poly-L-lysine; Sigma-Aldrich), maintained in NeuroBasal™ Medium supplemented with 2% B-27 and transfected at DIV6.

Culture media and transfection reagents, if not otherwise indicated, were purchased from Gibco™ (ThermoFisher Scientific).