Nest building behavior has been intensely applied as a parameter for severity assessment in mice. In contrast, only a limited number of studies have reported nest building data from rats. Here, we assessed nest building in rats in two different facilities addressing the hypotheses that the vendor, previous experience with the nesting material as well as sex of the rats has an impact on the performance. Data from two study sites and three raters were compared to obtain information about the robustness of nest complexity scoring. The findings demonstrate a generally poor nest building performance in rats with a pronounced day-to-day fluctuation, and site-specific differences. Application of a newly developed scoring system resulted in an intermediate inter-rater reliability. Previous experience with the nesting material did not exert a consistent impact on nest complexity scores. Sex differences proved to depend on vendor and animal facility without consistent findings supporting a superior performance in female or male rats. In conclusion, our findings argue against a robust and consistent influence of sex and familiarity with the nesting material. The comparison between facilities suggests that local conditions need to be considered as influencing factors, which should be explored in more detail by future multicenter approaches. Considering the day-to-day fluctuation and the intermediate inter-rater reliability, we highly recommend to base nest complexity evaluation on means from several subsequent days analyzed by a group of experienced raters.

Nongenetic optical control of neurons is a powerful technique to study and manipulate the function of the nervous system. This research has benchmarked the performance of organic electrolytic photocapacitor (OEPC) optoelectronic stimulators at the level of single mammalian cells: human embryonic kidney (HEK) cells with heterologously expressed voltage‐gated K+ channels and hippocampal primary neurons. OEPCs act as extracellular stimulation electrodes driven by deep red light. The electrophysiological recordings show that millisecond light stimulation of OEPC shifts conductance‐voltage plots of voltage‐gated K+ channels by ≈30 mV. Models are described both for understanding the experimental findings at the level of K+ channel kinetics in HEK cells, as well as elucidating interpretation of membrane electrophysiology obtained during stimulation with an electrically floating extracellular photoelectrode. A time‐dependent increase in voltage‐gated channel conductivity in response to OEPC stimulation is demonstrated. These findings are then carried on to cultured primary hippocampal neurons. It is found that millisecond time‐scale optical stimuli trigger repetitive action potentials in these neurons. The findings demonstrate that OEPC devices enable the manipulation of neuronal signaling activities with millisecond precision. OEPCs can therefore be integrated into novel in vitro electrophysiology protocols, and the findings can inspire in vivo applications.

Successful treatment of glioblastoma multiforme (GBM), the most lethal tumor of the brain, is presently hampered by (i) the limits of safe surgical resection and (ii) “shielding” of residual tumor cells from promising chemotherapeutic drugs such as Gemcitabine (Gem) by the blood brain barrier (BBB). Here, the vastly greater GBM cell‐killing potency of Gem compared to the gold standard temozolomide is confirmed, moreover, it shows neuronal cells to be at least 104‐fold less sensitive to Gem than GBM cells. The study also demonstrates the potential of an electronically‐driven organic ion pump (“GemIP”) to achieve controlled, targeted Gem delivery to GBM cells. Thus, GemIP‐mediated Gem delivery is confirmed to be temporally and electrically controllable with pmol min−1 precision and electric addressing is linked to the efficient killing of GBM cell monolayers. Most strikingly, GemIP‐mediated GEM delivery leads to the overt disintegration of targeted GBM tumor spheroids. Electrically‐driven chemotherapy, here exemplified, has the potential to radically improve the efficacy of GBM adjuvant chemotherapy by enabling exquisitely‐targeted and controllable delivery of drugs irrespective of whether these can cross the BBB.

No abstract

Co1–xMnxFe2O4 ferrite nanoparticles have been synthesized by employing a microwave‐stimulated technique under non‐hydrolytic conditions. Structural, chemical, and morphological characterizations were carried out by XRD, SEM‐EDS, and TEM techniques. The stability of the nanoparticles and their tendency to form agglomerates were investigated by dynamic light scattering, exploiting the effect of different biological environments and protein stabilization. It was shown that bovine serum albumin adsorption was dependent upon the concentration and chemical composition of the nanaoparticle, showing higher affinities with increasing Co2+ content. The cytotoxicities of the nonsurface‐blocked Co1–xMnxFe2O4 nanoparticles were assessed for three cell lines: phagocytic murine macrophage (J774.E), cancer fibroblast human osteosarcoma (HTB), and mesenchymal stem cells derived from human adipose tissue (ASCs). The results indicate that the cytotoxic response strongly depends on the particle concentration as well as the type of cell line.