Fig. 4

Desorption characteristic of BDNF from BDNF-PAMAM and PEG-ylated BDNF-PAMAM nanoparticles with differently charged dendrimer core in cell culture lysates and supernatant under carriers loading of protein concentrations equal to 0.1 mgL⁻¹. BDNF detection by ELISA over 24 h in cells incubated with PAMAM 5.5 (no BDNF), PAMAM 5.5- BDNF, PAMAM 5.5- BDNF-PEG, PAMAM 6 (no BDNF), PAMAM6—BDNF, PAMAM 6- BDNF-PEG. The data represent means ± SD for five experiments. Data distribution was tested using Shapiro–Wilk test. To compare two analysed datasets the unpaired t-test was used. The analysis of variances between different time-points was performed using one-way ANOVA. *—p < 0.05, **—p < 0.01, ***—p < 0.001.In supernatants from control cells BDNF, was released at the concentration of 4 ngL⁻¹. Interestingly, we observed that the application of positively as well as negatively charged dendrimers (6 and 5.5 generation, respectively) to the cell culture significantly decreased BDNF concentration in cells supernatant (Fig. 4). There was no detectable BDNF concentration in cell lysates, neither in controls nor after treating PAMAM 5.5 or PAMAM 6 dendrimers. We also observed that BDNF concentration in cell supernatant was significantly lower in the case of PAMAM5.5- compared to the PAMAM6-based nanoparticles