Search results for " composites"

Polymeric hepatitis C virus non-structural protein 5A nanocapsules induce intrahepatic antigen-specific immune responses

2016

Targeting antigen combined with adjuvants to hepatic antigen-presenting cells (APCs) is essential for the induction of intrahepatic T cellular immunity controlling and resolving viral infections of the liver. Intravenous injection of antigen-loaded nanoparticles is a promising approach for the delivery of antigens to liver APCs. Accordingly, polymeric nanocapsules (NCs) synthesized exclusively of hepatitis C virus non-structural protein 5A (NS5A) and the adjuvant monophosphoryl lipid A (MPLA) adsorbed to the nanocapsule surface were developed. Aim of the present study was the evaluation of the in vitro and in vivo behavior of MPLA-functionalized NS5A-NCs regarding the interaction with liver…

Cohesive Model for the Simulation of Crack Initiation and Propagation in Mixed-Mode I/II in Composite Materials

2019

A cohesive element able to connect and simulate crack growth between independently modeled finite element subdomains with non-matching meshes is proposed and validated. The approach is based on penalty constraints and has several advantages over conventional FE techniques in disconnecting two regions of a model during crack growth. The most important is the ability to release portion of the interface that are smaller than the local finite element length. Thus, the growth of delamination is not limited to advancing by releasing nodes of the FE model, which is a limitation common to the methods found in the literature. Furthermore, it is possible to vary the penalty parameter within the cohes…

Binding and neurotoxicity mitigation of toxic tau oligomers by synthetic heparin like oligosaccharides.

2018

Well-defined heparin like oligosaccharides up to decasaccharides were synthesized. It was discovered for the first time that heparin oligosaccharides, as short as tetrasaccharides, can bind with the most toxic tau species, i.e., tau oligomers with nM KD. The binding significantly reduced the cellular uptake of toxic tau oligomers and protected the cells from tau oligomer induced cytotoxicity.

Bi-layered polyurethane – Extracellular matrix cardiac patch improves ischemic ventricular wall remodeling in a rat model

2016

As an intervention to abrogate ischemic cardiomyopathy, the concept of applying a temporary, local patch to the surface of the recently infarcted ventricle has been explored from a number of design perspectives. Two important features considered for such a cardiac patch include the provision of appropriate mechanical support and the capacity to influence the remodeling pathway by providing cellular or biomolecule delivery. The objective of this report was to focus on these two features by first evaluating the incorporation of a cardiac extracellular matrix (ECM) component, and second by evaluating the impact of patch anisotropy on the pathological remodeling process initiated by myocardial …

Monocyte preseeding leads to an increased implant bed vascularization of biphasic calcium phosphate bone substitutes via vessel maturation

2016

The present study analyzes the influence of the addition of monocytes to a biphasic bone substitute with two granule sizes (400-700 μm and 500-1000 μm). The majority of the added monocytes was detectable as mononuclear cells, while also low amounts of (chimeric) multinucleated giant cells (MNGCs) were found. No increase in the total number of MNGCs was established, but a significantly increased percent vascularization. Altogether, the results show that the added monocytes become involved in the tissue response to a biomaterial without marked changes in the overall reaction. Monocyte addition enables an increased implant bed vascularization especially via induction of vessel maturation and, …

Heterogeneity of biomaterial-induced multinucleated giant cells: Possible importance for the regeneration process?

2015

Biomaterial-associated multinucleated giant cells (BMGCs) have been found within the implantation beds of many different biomaterials. However, their exact differentiation and their involvement in the inflammatory and healing events of the foreign body response still remain mostly unclear. Silk fibroin (SF) scaffolds, which induces a tissue reaction involving both macrophages and BMGCs, was implanted in the subcutaneous connective tissue of four CD-1 mice for 15 days using an established subcutaneous implantation model. Analysis of macrophage polarization and BMGCs was performed by immunohistochemcial detection of pro- (cyclooxygenase-2 (COX-2), C-C chemokine receptor type 7 (CCR7), nuclear…

The development of a tissue-engineered tracheobronchial epithelial model using a bilayered collagen-hyaluronate scaffold

2016

Today, chronic respiratory disease is one of the leading causes of mortality globally. Epithelial dysfunction can play a central role in its pathophysiology. The development of physiologically-representative in vitro model systems using tissue-engineered constructs might improve our understanding of epithelial tissue and disease. This study sought to engineer a bilayered collagen-hyaluronate (CHyA-B) scaffold for the development of a physiologically-representative 3D in vitro tracheobronchial epithelial co-culture model. CHyA-B scaffolds were fabricated by integrating a thin film top-layer into a porous sub-layer with lyophilisation. The film layer firmly connected to the sub-layer with del…

In vitroassessment of the biological response of Ti6Al4V implants coated with hydroxyapatite microdomains

2016

Dental implantology is still an expanding field of scientific study because of the number of people that receive dental therapies throughout their lives worldwide. Recovery times associated to dental surgery are still long and demand strategies to improve integration of metallic devices with hard tissues. In this work, an in vitro ceramic coating is proposed to improve and accelerate osseointegration of titanium surfaces conceived to be used as dental implants or hip or knee prosthesis, shaped either as dishes or screws. Such coating consists of hydroxyapatite microdomains on the implant surfaces obtained in vitro by immersion of titanium alloy samples (Ti6Al4V) in a simulated body fluid. T…

2017

We have engineered polymer-based microenvironments that promote vasculogenesis both in vitro and in vivo through synergistic integrin-growth factor receptor signalling. Poly(ethyl acrylate) (PEA) triggers spontaneous organization of fibronectin (FN) into nanonetworks which provide availability of critical binding domains. Importantly, the growth factor binding (FNIII12-14) and integrin binding (FNIII9-10) regions are simultaneously available on FN fibrils assembled on PEA. This material platform promotes synergistic integrin/VEGF signalling which is highly effective for vascularization events in vitro with low concentrations of VEGF. VEGF specifically binds to FN fibrils on PEA compared to …

Asymmetric synthesis of 3,3′-pyrrolidinyl-dispirooxindoles via a one-pot organocatalytic Mannich/deprotection/aza-Michael sequence

2016

Chemical communications 52, 2249-2252 (2016). doi:10.1039/C5CC10057G