Search results for " Materials Science"
showing 10 items of 7414 documents
Mapping brain activity with flexible graphene micro-transistors
2016
arXiv:1611.05693v1.-- et al.
Silver nanoparticle based coatings enhance adipogenesis compared to osteogenesis in human mesenchymal stem cells through oxidative stress.
2020
Silver nanoparticle (AgNP) based antibacterial surfaces were fabricated using plasma polymerization technology and their effects on differentiation of human bone-marrow derived mesenchymal stem cells (hMSCs) were investigated in this study. The results showed that AgNP coated surfaces do not affect the initial adhesion, spreading and proliferation of hMSCs. Furthermore, the silver coated surface promoted adipogenic differentiation of hMSCs as demonstrated by more accumulation of lipid droplets and upregulation of adipogenesis-related genes such as peroxisome proliferator activated receptor gamma (PPAR gamma), adipocyte determination and differentiation factor (ADD1) and CCAAT/enhancer bindi…
Single nanogranules preserve intracrystalline amorphicity in biominerals.
2015
We revisit the ultrastructural features of different calcareous biominerals and identify remarkable similarities: taxonomically very distant species show a common nanogranular structure, even if different extracellular secretion patterns are employed or calcium carbonate polymorphs formed. By these analyses, we elucidate the locus of the small fraction of intracrystalline organic matrix revealing its intergranular character and localize the intracrystalline amorphous calcium carbonate moiety commonly found in mesocrystalline biominerals and provide a first explanation for the pathway by which it is preserved.
Nanoscale Engineering of Designer Cellulosomes.
2016
Biocatalysts showcase the upper limit obtainable for high-speed molecular processing and transformation. Efforts to engineer functionality in synthetic nanostructured materials are guided by the increasing knowledge of evolving architectures, which enable controlled molecular motion and precise molecular recognition. The cellulosome is a biological nanomachine, which, as a fundamental component of the plant-digestion machinery from bacterial cells, has a key potential role in the successful development of environmentally-friendly processes to produce biofuels and fine chemicals from the breakdown of biomass waste. Here, the progress toward so-called "designer cellulosomes", which provide an…
The collagen type I segment long spacing (SLS) and fibrillar forms: Formation by ATP and sulphonated diazo dyes.
2016
The collagen type I segment long spacing (SLS) crystallite is a well-ordered rod-like molecular aggregate, ∼300nm in length, which is produced in vitro under mildly acidic conditions (pH 2.5-3.5) in the presence of 1mM ATP. The formation of the SLS crystallite amplifies the inherent linear structural features of individual collagen heterotrimers, due to the punctate linear distribution and summation of the bulkier amino acid side chains along the length of individual collagen heterotrimers. This can be correlated structurally with the 67nm D-banded collagen fibril that is found in vivo, and formed in vitro. Although first described many years ago, the range of conditions required for ATP-in…
Polyphosphate as a Bioactive and Biodegradable Implant Material: Induction of Bone Regeneration in Rats
2016
Inorganic polyphosphate (polyP) is a naturally occurring polymer that is bioresorbable and anabolically active on bone forming cells in vitro. In order to demonstrate if polyP also shows morphogenetic activity in vivo, animal studies are performed applying the rat calvarial defect model. Poly(D,L-lactide-co-glycolide) (PLGA) microspheres with a narrow size distribution (≈820 μm) are prepared, containing either encapsulated polyP or β-tricalcium phosphate (β-TCP), used as a reference material. Discs are prepared from the microspheres and inserted into 10 mm large defects created in the calvaria of rats. Both the formation of COL-I and the expression of ALP is upregulated, as well as the exte…
Vaccination with trifunctional nanoparticles that address CD8+ dendritic cells inhibits growth of established melanoma
2016
Aim: We wanted to assess the potency of a trifunctional nanoparticle (NP) that targeted and activated CD8+ dendritic cells (DC) and delivered an antigen to induce antitumor responses. Materials & methods: The DC targeting and activating properties of ferrous NPs conjugated with immunostimulatory CpG-oligonucleotides, anti-DEC205 antibody and ovalbumin (OVA) as a model antigen to induce antigen-specific T-cell responses and antitumor responses were analyzed. Results: OVA-loaded NP conjugated with immunostimulatory CpG-oligonucleotides and anti-DEC205 antibody efficiently targeted and activated CD8+ DC in vivo, and induced strong OVA-specific T-cell activation. Vaccination of B16/OVA tum…
Silver Atomic Quantum Clusters of Three Atoms for Cancer Therapy: Targeting Chromatin Compaction to Increase the Therapeutic Index of Chemotherapy
2018
Nanomaterials with very low atomicity deserve consideration as potential pharmacological agents owing to their very small size and to their properties that can be precisely tuned with minor modifications to their size. Here, it is shown that silver clusters of three atoms (Ag3 -AQCs)-developed by an ad hoc method-augment chromatin accessibility. This effect only occurs during DNA replication. Coadministration of Ag3 -AQCs increases the cytotoxic effect of DNA-acting drugs on human lung carcinoma cells. In mice with orthotopic lung tumors, the coadministration of Ag3 -AQCs increases the amount of cisplatin (CDDP) bound to the tumor DNA by fivefold without modifying CDDP levels in normal tiss…
Proteins as Functional Units of Biocalcification – An Overview
2016
High-throughput approaches such as genomics, transcriptomics and proteomics have led to the discovery of a larger set of biomineralization genes than previously foreseen. These gene lists are often difficult to decode in light of the current models of calcification. Here we overview the proteins available in UniProt (Universal Protein Resource), that were identified directly in metazoan calcium carbonate mineralized structures or known to have direct key-functions in calcification processes. Functional annotation of the protein datasets using Gene Ontology reveals that functions like carbohydrate binding, structural and catalytic activities (e.g. hydrolase) are commonly represented across t…
Evidence-Based Clinical Use of Nanoscale Extracellular Vesicles in Nanomedicine
2016
collaboration au projet H2020 European Cooperation in Science and Technology (COST) program European Network on Microvesicles and Exosomes in Health and Disease (ME-HAD); International audience; Recent research has demonstrated that all body fluids assessed contain substantial amounts of vesicles that range in size from 30 to 1000 nm and that are surrounded by phospholipid membranes containing different membrane microdomains such as lipid rafts and caveolae. The most prominent representatives of these so-called extracellular vesicles (EVs) are nanosized exosomes (70-150 nm), which are derivatives of the endosomal system, and microvesicles (100-1000 nm), which are produced by outward budding…