We report for the first time on neuronal signaling for the evaluation of interactions between native plasmamembrane and polyamidoamine (PAMAM) dendrimers. Generation 5 polycationic (G5-NH2), novel β-D-glucopyranose- conjugated G5-NH2 and generation 4.5 polyanionic (G4.5-COONa) polyamidoamine (PAMAM) dendrimers (1-0.0001 mg/ml) were applied in acute brain slices. Functional toxicity assessments-validated by fluorescence imaging of dead cells-were performed by employing electrophysiological indicators of plasma membrane breakdown and synaptic transmission relapse. Irreversible membrane depolarization and decrease of membrane resistance predicted substantial functional neurotoxicity of unmodified G5-NH2, but not of the G4.5-COONa PAMAM dendrimers. Model calculations suggested that freely moving protonated NH2 groups of terminal monomeric units of PAMAM dendrimers may be able directly destroy the membrane or inhibit important K+ channel function via contacting the positively charged NH2. In accordance, conjugation of surface amino groups by β-D-glucopyranose units reduced functional neurotoxicity that may hold great potential for biomedical applications.
- Functional neurotoxicity indicators
- Imaging cell death
- Molecular simulation
- Polycationic and polyanionic PAMAM dendrimers