Tropoelastin coated PLLA-PLGA scaffolds promote vascular network formation

The robust repair of large wounds and tissue defects relies on blood flow. This vascularization is the major challenge faced by tissue engineering on the path to forming viable thick, implantable tissue constructs. Without the presence of this vascular network, oxygen and nutrients cannot reach the cells located far from host blood vessels. To create viable constructs, tissue engineering takes advantage of the mechanical properties of synthetic materials, while combining them with extracellular matrix (ECM) proteins to create a natural environment for the tissue-specific cells. Tropoelastin, the precursor of the elastin, is the ECM protein responsible for elasticity in all elastic tissues in the body, including robust blood vessels. We seeded human adipose microvascular endothelial cells (HAMECs) combined with mesenchymal stem cells (MSCs) on poly(L-lactic acid)/poly(lactide-co-glycolide) (PLLA/PLGA) scaffolds treated with tropoelastin, and examined the morphology, expansion and maturity of the newly formed vessels. Our in vitro results demonstrate that the treated scaffolds show a more expanded, complex and developed vascularization, in comparison to the untreated control group. To further explore the benefits of tropoelastin-treated scaffolds, we implanted pre-vascularized constructs within the mouse abdominal wall muscle by replacing a piece of the muscle with the engineered constructs. Within 12 days after implantation, we saw enhanced perfusion by host blood vessels. These results point to the great potential of these combined materials in promoting the vascularization of implanted tissue engineered constructs

Potential involvement of F0F1-ATP(synth)ase and reactive oxygen species in apoptosis induction by the antineoplastic agent erucylphosphohomocholine in glioblastoma cell lines: A mechanism for induction of apoptosis via the 18 kDa mitochondrial translocator protein

Erucylphosphohomocholine (ErPC3, Erufosine™) was reported previously to induce apoptosis in otherwise highly apoptosis-resistant malignant glioma cell lines while sparing their non-tumorigenic counterparts. We also previously found that the mitochondrial 18 kDa Translocator Protein (TSPO) is required for apoptosis induction by ErPC3. These previous studies also suggested involvement of reactive oxygen species (ROS). In the present study we further investigated the potential involvement of ROS generation, the participation of the mitochondrial respiration chain, and the role of the mitochondrial FOF1-ATP(synth)ase in the pro-apoptotic effects of ErPC3 on U87MG and U118MG human glioblastoma cell lines. For this purpose, cells were treated with the ROS chelator butylated hydroxyanisole (BHA), the mitochondrial respiration chain inhibitors rotenone, antimycin A, myxothiazol, and the uncoupler CCCP. Also oligomycin and piceatannol were studied as inhibitors of the FO and F1 subunits of the mitochondrial FOF1-ATP(synth)ase, respectively. BHA was able to attenuate apoptosis induction by ErPC3, including mitochondrial ROS generation as determined with cardiolipin oxidation, as well as collapse of the mitochondrial membrane potential (Δψm). Similarly, we found that oligomycin attenuated apoptosis and collapse of the Δψm, normally induced by ErPC3, including the accompanying reductions in cellular ATP levels. Other inhibitors of the mitochondrial respiration chain, as well as piceatannol, did not show such effects. Consequently, our findings strongly point to a role for the FO subunit of the mitochondrial FOF1-ATP(synth)ase in ErPC3-induced apoptosis and dissipation of Δψm as well as ROS generation by ErPC3 and TSPO

Scientific, sustainability and regulatory challenges of cultured meat

Producing meat without the drawbacks of conventional animal agriculture would greatly contribute to future food and nutrition security. This Review Article covers biological, technological, regulatory and consumer acceptance challenges in this developing field of biotechnology. Cellular agriculture is an emerging branch of biotechnology that aims to address issues associated with the environmental impact, animal welfare and sustainability challenges of conventional animal farming for meat production. Cultured meat can be produced by applying current cell culture practices and biomanufacturing methods and utilizing mammalian cell lines and cell and gene therapy products to generate tissue or nutritional proteins for human consumption. However, significant improvements and modifications are needed for the process to be cost efficient and robust enough to be brought to production at scale for food supply. Here, we review the scientific and social challenges in transforming cultured meat into a viable commercial option, covering aspects from cell selection and medium optimization to biomaterials, tissue engineering, regulation and consumer acceptance

Microstructure and morphology evolution in chemical solution deposited semiconductor films: 3. PbSe on GaAs vs. Si substrate

The microstructure and morphology evolution in nanocrystalline PbSe films chemically deposited on GaAs(100) and GaAs(111) substrates were compared to PbSe films on Si(100) under the same conditions. On GaAs substrates, dense and continuous PbSe films were obtained. We show that the temperature dependent morphological changes on GaAs substrates occurred as a result of increased sample thickness due to higher reaction rates. Notably, the deposition of PbSe on Si(100) did not lead to continuous films and no preferred orientation was observed. The improved wetting between PbSe and GaAs appears to be a key factor responsible for the differences observed on the two substrates

Microstructure and morphology evolution in chemical solution deposited PbSe films on GaAs(100)

We have studied the microstructure and morphology evolution in PbSe films chemically deposited on GaAs(100) substrates. The films consisted of a single phase of nanocrystalline rocksalt PbSe. The deposition temperature was found to be an important parameter which strongly influences the film morphology. A gradual transition to strong (111) texture was obtained with increasing deposition temperature, accompanied by a significant increase in crystallite size. Transmission electron microscopy (TEM) cross-sections showed two distinct regions. A layer of small, rounded crystals near the GaAs/PbSe interface above which a second region composed of columnar, $\langle$111$\rangle$ oriented crystallites was observed. High resolution TEM and Fourier analysis showed that the first layer of crystallites are in epitaxial registry with the GaAs substrate, in spite of the large (8%) lattice mismatch and the presence of a thin, amorphous interfacial layer