Adhesion and proliferation of fibroblasts on cluster-assembled nanostructured carbon films: the role of surface morphology

Zeolitic imidazolate framework-derived porous carbon enhances methanogenesis by facilitating interspecies electron transfer: Understanding fluorimetric and electrochemical responses of multi-layered extracellular polymeric substances

Modulating microbial electron transfer during anaerobic digestion can significantly improve syntrophic interactions for enhanced biogas production. As a carbonaceous conductive material, zeolite imidazolate framework-67 (ZIF-67)-derived porous carbon (PC) was hypothesized to act as a microbial electron transfer highway and assessed with respect to understanding the fluorimetric and electrochemical responses of multilayered extracellular polymeric substances (EPS). The highest biomethane yield (614.0 mL/g) from ethanol was achieved in the presence of 100 mg/L PC prepared at a carbonization temperature of 800 °C (PC-800), which was 28.2% higher than that without PC addition. Electrochemical analysis revealed that both the redox peak currents and conductivity of the methanogenic sludge increased, while the free charge transfer resistance decreased with PC-800 addition. The conductive PC-800 potentially functioned as an abiotic electron conduit to promote direct interspecies electron transfer, thereby resulting in decreased expression of functional genes associated with electrically conductive pili (e-pili) and hemeproteins. Additionally, PC-800 stimulated the secretion of redox-active humic substances (HSs), and excitation emission matrix spectra analysis indicated that the largest increase in percent fluorescence response of HSs occurred in the tightly bound EPS (TB-EPS) with addition of PC-800. This was attributed to the strong complexation ability of PC-800 particles to hydroxyl/carboxylic/phenolic moieties of HSs contained in the TB-EPS. Microbial analysis revealed that syntrophic/exoelectrogenic bacteria such as Pelotomaculum and Syntrophomonas, as well as hydrogenotrophic/electrotrophic methanogens such as Methanoculleus and Methanobacterium, were enriched in methanogenic sludge with adding PC-800. This study provided comprehensive insights for understanding the interactions among ZIF-derived PC, methanogenic microorganisms and their multilayered EPS.

Bisepoxide-Jeffamine microgel synthesis and application toward heterogeneous surface morphology for differential neuronal/non-neuronal cell responses in vitro

Herein, a new non-vinylic type of cationic microgels (MG) was readily prepared from ethylene glycol diglycidyl ether and Jeffamine T-403 in water. The MG was responsive to both temperature and pH, and oxidatively stable as demonstrated by the hydrogen peroxide study. Using glass as a model substrate, its surface was easily imparted with a heterogeneous morphology by simply adsorbing MG dispersed in basic solution. Specifically, the morphology features patches made of a monolayer of connected yet individually recognizable MG. Through in vitro cell studies, we show that a mere change of the extent of surface coverage by such a patchy morphology can strike a balance in promoting adhesion and differentiation of neuron-like PC-12 cells and primary cortical neurons of chick embryo, without soliciting proliferative response from non-neuronal cells of NIH3T3 fibroblast and CTX astrocyte. This simple yet unconventional surface morphology created by MG could be leveraged in the future as an alternative strategy for neural interface engineering.

Biofunctionalized 3-D Carbon Nano-Network Platform for Enhanced Fibroblast Cell Adhesion

Carbon nanomaterials have been investigated for various biomedical applications. In most cases, however, these nanomaterials must be functionalized biologically or chemically due to their biological inertness or possible cytotoxicity. Here, we report the development of a new carbon nanomaterial with a bioactive phase that significantly promotes cell adhesion. We synthesize the bioactive phase by introducing self-assembled nanotopography and altered nano-chemistry to graphite substrates using ultrafast laser. To the best of our knowledge, this is the first time that such a cytophilic bio-carbon is developed in a single step without requiring subsequent biological/chemical treatments. By controlling the nano-network concentration and chemistry, we develop platforms with different degrees of cell cytophilicity. We study quantitatively and qualitatively the cell response to nano-network platforms with NIH-3T3 fibroblasts. The findings from the in vitro study indicate that the platforms possess excellent biocompatibility and promote cell adhesion considerably. The study of the cell morphology shows a healthy attachment of cells with a well-spread shape, overextended actin filaments, and morphological symmetry, which is indicative of a high cellular interaction with the nano-network. The developed nanomaterial possesses great biocompatibility and considerably stimulates cell adhesion and subsequent cell proliferation, thus offering a promising path toward engineering various biomedical devices.

The basement membrane of the isolated rat colonic mucosa. A light, electron and atomic force microscopy study

Basement membranes (BM) are structures of the extracellular matrix (ECM), which are involved in epithelial barriers, but also play an important role in processes such as cell adhesion, cell growth and tissue healing. The aim of this study was to investigate possible effects of cell removal on the structure of the BM of the colonic mucosa. The superficial epithelium was removed with EDTA and the samples were then mechanically fixed for immunohistochemistry, TEM, SEM and AFM. For SEM and AFM, some samples were also prepared according to the OTO method. BM marker proteins were detected after cell removal by immunohistochemistry, indicating that BM remains. However, a lamina lucida (LL) was no longer visible in TEM, it disappeared and the BM became slightly thinner. The surface topography of the BM is characterized by the presence of globules, fenestrations and pore-like structures, which were visualized with SEM and AFM. Noteworthy is the visualization for the first time with AFM of a 3D network of fine fibers and filaments ("cords"), which very much resembled that described with TEM by Inoue (1994). An unresolved question is whether the pore-like structures observed in this study, especially with SEM, actually correspond to the pores of the BM whose existence has been demonstrated functionally. In conclusion, the structural patterns and changes described could be considered as a reference to evaluate the effects of other decellularization protocols on BMs, such as those used in tissue engineering.