Structural and physical characteristics of the dermal decellularized structures evaluation

Introduction: Decellularized biomaterials derived from the biological tissues are ideal for tissue engineering applications because they mimic the biochemical composition of the native tissue. The physical and structural properties of the scaffold are important in the fields of tissue engineering and regenerative medicine. Material and methods: Study material was 20 decellularized dermal grafts. 10 samples were obtained from piglets slaughtered in the slaughterhouse. Other tissues (n=10) were received from the donor from the Human Tissue and Cell Bank of the Republic of Moldova. Extracellular matrices were obtained by decellularization with 0.5% sodium dodecyl sulfate/0.1% EDTA solution. The evaluation of the structural characteristics was carried out by the histological examination with hematoxylin and eosin, scanning electron microscopy and the quantification of the amount of deoxyribonucleic acids. Assessment of the physical characteristics included analysis of extracellular matrix volume porosity, density, and swelling rate. Results: Histological examination revealed fewer cells in decellularized tissues compared to non-decellularized ones. More than 80.5% of nucleic acids were removed from porcine matrix and 82.5% of genetic material – from decellularized human dermal structures. A mean correlation and inverse dependence of -0.43 was shown between porosity and swelling rate of decellularized dermis. Conclusions: The decellularization process significantly (P<0.05) removed the cellular components while preserving the connective three-dimensional structure of the dermal matrices clearly shown by quantification of the amount of DNA and microscopic examination of the structures

The effectiveness of the tissue engineering in the obtaining of the biological materials from the extracellular matrix

Background: The present work describes the possibility of manufacturing biomaterials from the extracellular matrix for the treatment of the skin wounds. Biomedical collagen-based materials are clinically effective. Collagen is the most abundant and major component of the skin. Porcine collagen is almost similar to the human collagen, it is not immunogenic when used for the therapeutic purposes. Biomaterials can be obtained from the decellularized dermis, being a matrix rich in the collagen and glycoproteins. Material and methods: 3 parallel groups of biomaterials were established and the average value was calculated. To ensure the effectiveness of the decellularization process, the decellularized porcine dermis was compared with the intact sample using qualitative and quantitative criteria. Results: Histologically, the decellularized tissues revealed the presence of fewer cells. As a result, were removed approximately 80.5% of the genetic material from porcine dermal structures, demonstrated by the spectrophotometric quantification of deoxyribonucleic acid. In vitro graft degradation study in 0.01 M phosphate buffer pH 7.4 combined with collagenase, demonstrated a significant (p < 0.05) loss of collagen sponge mass by 100% over one hour in the group II compared to the decellularized dermis in group I which decreased in the weight by 91.3% during 35 hours. Conclusions: Acellular biomaterials are immunologically inert, have hydrophilic and biodegradable properties, thus they can play a key role in the wound care, exerting the transfer of the bioactive molecules and drugs directly into the wound

Sensitivity of human pluripotent stem cells to insulin precipitation induced by peristaltic pump-based medium circulation: Considerations on process development

Controlled large-scale production of human pluripotent stem cells (hPSCs) is indispensable for their envisioned clinical translation. Aiming at advanced process development in suspension culture, the sensitivity of hPSC media to continuous peristaltic pump-based circulation, a well-established technology extensively used in hydraulically-driven bioreactors, was investigated. Unexpectedly, conditioning of low protein media (i.e. E8 and TeSR-E8) in a peristaltic pump circuit induced severe viability loss of hPSCs cultured as aggregates in suspension. Optical, biochemical, and cytological analyses of the media revealed that the applied circulation mode resulted in the reduction of the growth hormone insulin by precipitation of micro-sized particles. Notably, in contrast to insulin depletion, individual withdrawal of other medium protein components (i.e. bFGF, TGFβ1 or transferrin) provoked minor reduction of hPSC viability, if any. Supplementation of the surfactant glycerol or the use of the insulin analogue Aspart did not overcome the issue of insulin precipitation. In contrast, the presence of bovine or human serum albumin (BSA or HSA, respectively) stabilized insulin rescuing its content, possibly by acting as molecular chaperone-like protein, ultimately supporting hPSC maintenance. This study highlights the potential and the requirement of media optimization for automated hPSC processing and has broad implications on media development and bioreactor-based technologies. © 2017 The Author(s).Horizon 2020/Marie Skłodowska-Curie Individual Fellowship POSEIDONDFG/EXC/REBIRTHDFG/EXC62/3DFG/ZW64/4-1BMBF/13N12606BMBF/13N14086StemBANCCH2020/TECHNOBEATHannover Medical School internal program (HiLF)Joachim Herz Stiftun

Advanced Hybrid GaN/ZnO Nanoarchitectured Microtubes for Fluorescent Micromotors Driven by UV Light

The development of functional microstructures with designed hierarchical and complex morphologies and large free active surfaces offers new potential for improvement of the pristine microstructures properties by the synergistic combination of microscopic as well as nanoscopic effects. In this contribution, dedicated methods of transmission electron microscopy (TEM) including tomography are used to characterize the complex hierarchically structured hybrid GaN/ZnO:Au microtubes containing a dense nanowire network on their interior. The presence of an epitaxially stabilized and chemically extremely stable ultrathin layer of ZnO on the inner wall of the produced GaN microtubes is evidenced. Gold nanoparticles initially trigger the catalytic growth of solid solution phase (Ga1– xZnx)(N1– xOx) nanowires into the interior space of the microtube, which are found to be terminated by AuGa-alloy nanodots coated in a shell of amorphous GaOx species after the hydride vapor phase epitaxy process. The structural characterization suggests that this hierarchical design of GaN/ZnO microtubes could offer the potential to exhibit improved photocatalytic properties, which are initially demonstrated under UV light irradiation. As a proof of concept, the produced microtubes are used as photocatalytic micromotors in the presence of hydrogen peroxide solution with luminescent properties, which are appealing for future environmental applications and active matter fundamental studies. © 2019 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Aero-Ga2O3 Nanomaterial Electromagnetically Transparent from Microwaves to Terahertz for Internet of Things Applications

In this paper, fabrication of a new material is reported, the so-called Aero-Ga2O3 or Aerogallox, which represents an ultra-porous and ultra-lightweight three-dimensional architecture made from interconnected microtubes of gallium oxide with nanometer thin walls. The material is fabricated using epitaxial growth of an ultrathin layer of gallium nitride on zinc oxide microtetrapods followed by decomposition of sacrificial ZnO and oxidation of GaN which according to the results of X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS) characterizations, is transformed gradually in β-Ga2O3 with almost stoichiometric composition. The investigations show that the developed ultra-porous Aerogallox exhibits extremely low reflectivity and high transmissivity in an ultrabroadband electromagnetic spectrum ranging from X-band (8-12 GHz) to several terahertz which opens possibilities for quite new applications of gallium oxide, previously not anticipated

Ultrafast Third-Order Nonlinear Optical Response Excited by fs Laser Pulses at 1550 nm in GaN Crystals

The ultrafast third-order optical nonlinearity of c-plane GaN crystal, excited by ultrashort (fs) high-repetition-rate laser pulses at 1550 nm, wavelength important for optical communications, is investigated for the first time by optical third-harmonic generation in non-phase-matching conditions. As the thermo-optic effect that can arise in the sample by cumulative thermal effects induced by high-repetition-rate laser pulses cannot be responsible for the third-harmonic generation, the ultrafast nonlinear optical effect of solely electronic origin is the only one involved in this process. The third-order nonlinear optical susceptibility of GaN crystal responsible for the third-harmonic generation process, an important indicative parameter for the potential use of this material in ultrafast photonic functionalities, is determined

Viability and proliferation of endothelial cells upon exposure to GaN nanoparticles

Nanotechnology is a rapidly growing and promising field of interest in medicine; however, nanoparticle–cell interactions are not yet fully understood. The goal of this work was to examine the interaction between endothelial cells and gallium nitride (GaN) semiconductor nanoparticles. Cellular viability, adhesion, proliferation, and uptake of nanoparticles by endothelial cells were investigated. The effect of free GaN nanoparticles versus the effect of growing endothelial cells on GaN functionalized surfaces was examined. To functionalize surfaces with GaN, GaN nanoparticles were synthesized on a sacrificial layer of zinc oxide (ZnO) nanoparticles using hydride vapor phase epitaxy. The uptake of GaN nanoparticles by porcine endothelial cells was strongly dependent upon whether they were fixed to the substrate surface or free floating in the medium. The endothelial cells grown on surfaces functionalized with GaN nanoparticles demonstrated excellent adhesion and proliferation, suggesting good biocompatibility of the nanostructured GaN