Despite the obvious advantages of gold nanoparticles for biomedical applications, controversial and incomplete toxicological data hamper their widespread use. Here, we present the results from an in vivo toxicity study using gold nanoparticles coated with polyethylene glycol (PEG-AuNPs). The pharmacokinetics and biodistribution of PEG-AuNPs were examined in the rat’s liver, lung, spleen, and kidney after a single i.v. injection (0.7 mg/kg) at different time intervals. PEG-AuNPs had a relatively long blood circulation time and accumulated primarily in the liver and spleen, where they remained for up to 28 days after administration. Increased cytoplasmic vacuolation in hepatocytes 24 h and 7 days after PEG-AuNPs exposure and apoptotic-like cells in white splenic pulp 24 h after administration has been detected, however, 28 days post-exposure were no longer observed. In contrast, at this time point, we identified significant changes in lipid metabolism, altered levels of liver injury markers, and elevated monocyte count, but without marked biological relevance. In blood cells, no DNA damage was present in any of the studied time intervals, with the exception of DNA breakage transiently detected in primary kidney cells 4 h post-injection. Our results indicate that the tissue accumulation of PEG-AuNPs might result in late toxic effects.

Data suitable for assembling a physiologically-based pharmacokinetic (PBPK) model for nanoparticles (NPs) remain relatively scarce. Therefore, there is a trend in extrapolating the results of in vitro and in silico studies to in vivo nanoparticle hazard and risk assessment. To evaluate the reliability of such approach, a pharmacokinetic study was performed using the same polyethylene glycol-coated gold nanoparticles (PEG-AuNPs) in vitro and in vivo. As in vitro models, human cell lines TH1, A549, Hep G2, and 16HBE were employed. The in vivo PEG-AuNP biodistribution was assessed in rats. The internalization and exclusion of PEG-AuNPs in vitro were modeled as first-order rate processes with the partition coefficient describing the equilibrium distribution. The pharmacokinetic parameters were obtained by fitting the model to the in vitro data and subsequently used for PBPK simulation in vivo. Notable differences were observed in the internalized amount of Au in individual cell lines compared to the corresponding tissues in vivo, with the highest found for renal TH1 cells and kidneys. The main reason for these discrepancies is the absence of natural barriers in the in vitro conditions. Therefore, caution should be exercised when extrapolating in vitro data to predict the in vivo NP burden and response to exposure.

We hereby report a successful design strategy for n-type semiconductor materials based on an analogy with efficient p-type semiconductors, by introducing electron-withdrawing groups while maintaining the symmetry of the molecules upon omitting one thiophene unit on each side of the oligoaryl core. Two series of dithienylnaphthalenes and quaterthiophenes substituted with various electron-withdrawing groups have been synthesised using Suzuki or Stille cross-coupling, and Knoevenagel condensation as key steps. The comparison of theoretical and experimental molecular properties related to the effect of electron-withdrawing groups is presented. Both the DFT-calculated and experimentally determined values of the energy gap between frontier orbitals have shown a decreasing trend in the order of perfluoroalkyl, acyl, perfluoroacyl, nitro, alkyldicyanovinyl and perfluoroalkyldicyanovinyl in both series. The X-ray analysis of five derivatives revealed almost planar geometry of the oligoaryl core with a herringbone or lamellar packing motif. The crystal structures of quaterthiophenes exhibited an s-cis conformation between the outer thiophenes in the crystals, in contrast to the theoretical prediction. Carbonyl-based compounds showed n-type behaviour as an active layer in OFET devices with an electron mobility of up to 0.57 cm² V⁻¹ s⁻¹.