Search results for "Biomaterial"

Electrospinning of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide-graft-polylactic acid to produce a fibrillar scaffold

2010

Abstract α,β-Poly( N -2-hydroxyethyl)- dl -aspartamide grafted with polylactic acid (PHEA- g -PLA) is a biocompatible and biodegradable amphiphilic copolymer that has been already employed to prepare a drug delivery system. In this study we have prepared for the first time a fibrillar scaffold from PHEA- g -PLA by the electrospinning of a solution of this copolymer in a mixture of N , N -dimethyl formamide (DMF) and acetone (80:20 vol/vol). The average diameter and the morphology of electrospun fibers were detected by scanning electron microscopy. Chemical degradation studies in phosphate buffer solution pH 7.4 have been performed until 15 days in order to obtain a preliminary information a…

Field-induced nanolithography for high-throughput pattern transfer.

2009

Flexible diphenylsulfone versus rigid dibenzothiophene-dioxide as acceptor moieties in donor-acceptor-donor TADF emitters for highly efficient OLEDs

2020

DG acknowledges funding from the ERDF PostDoc project No. 1.1.1.2/VIAA/1/16/177 . This research is/was funded by the European Regional Development Fund according to the supported activity ‘ Research Projects Implemented by World-class Researcher Groups ’ under Measure No. 01.2.2-LMT-K-718 . Ministry of Science and Technology (MOST), Taiwan , Grant No. MOST 106-2923-E-155-002-MY3 . This work was also supported by the Ministry of Education and Science of Ukraine (projects no. 0117U003908 and 0118U003862 ), and by the Olle Engkvist Byggmästare foundation (contract No. 189-0223 ). The quantum-chemical calculations were performed with computational resources provided by the High Performance Comp…

Ettringite surface chemistry: Interplay of electrostatic and ion specificity

2011

International audience; This paper presents a detailed experimental study combined with Monte Carlo (MC) simulations within the primitive model of the physical chemistry at the ettringite-water interface over a wide range of pH and bulk conditions for which ettringite exists thanks to its solubility in aqueous solutions. Ettringite, which is an important phase in hydrated cement-based systems, bears a permanent and positive structural charge. In contrast with previous studies, electrokinetic measurements together with the careful chemical analysis of the equilibrium solutions of the dispersions have brought strong support to designate sulfate as being the ion determining the potential. Simu…

Dielectrophoretic trapping of DNA origami.

2008

In this thesis three-dimensional tube-shaped DNA-origamis were dielectrophoretically trapped within lithographically fabricated nanoelectrodes. The origamis had been premade while the electrodes were fabricated specifically for these experiments with two different gapsizes, 150 nm and 400 nm. The aim of the work was to capture individual nanotubes in the gap between the electrodes by utilizing the dielectrophoretic forces present in the structure when a solution containing the origamis was put onto the electrodes and a voltage was applied. It was observed during the experiments that the success of the dielectrophoretic trapping depended strongly on the trapping conditions. This caused the t…

Novel molluskan biomineralization proteins retrieved from proteomics: a case study with upsalin.

2012

12 pages; International audience; The formation of the molluskan shell is regulated by an array of extracellular proteins secreted by the calcifying epithelial cells of the mantle. These proteins remain occluded within the recently formed biominerals. To date, many shell proteins have been retrieved, but only a few of them, such as nacreins, have clearly identified functions. In this particular case, by combining molecular biology and biochemical approaches, we performed the molecular characterization of a novel protein that we named Upsalin, associated with the nacreous shell of the freshwater mussel Unio pictorum. The full sequence of the upsalin transcript was obtained by RT-PCR and 5'/3…

Theoretical and experimental study of the role of cell-cell dipole interaction in dielectrophoretic devices: application to polynomial electrodes

2013

BACKGROUND: We aimed to investigate the effect of cell-cell dipole interactions in the equilibrium distributions in dielectrophoretic devices. METHODS: We used a three dimensional coupled Monte Carlo-Poisson method to theoretically study the final distribution of a system of uncharged polarizable particles suspended in a static liquid medium under the action of an oscillating non-uniform electric field generated by polynomial electrodes. The simulated distributions have been compared with experimental ones observed in the case of MDA-MB-231 cells in the same operating conditions. RESULTS: The real and simulated distributions are consistent. In both cases the cells distribution near the elec…

Engineering in-plane mechanics of electrospun polyurethane scaffolds for cardiovascular tissue applications

2021

Effective cardiovascular tissue surrogates require high control of scaffold structural and mechanical features to match native tissue properties, which are dependent on tissue-specific mechanics, function heterogenicity, and morphology. Bridging scaffold processing variables with native tissue properties is recognized as a priority for advancing biomechanical performance of biomedical materials and, when translated to the clinical practice, their efficacy. Accordingly, this study selected electrospinning on a rotating cylindrical target as an apparatus of broad application and mapped the relationship between key processing variables and scaffold mechanics and structure. This information was…

Bioengineered vascular scaffolds: the state of the art

2014

To date, there is increasing clinical need for vascular substitutes due to accidents, malformations, and ischemic diseases. Over the years, many approaches have been developed to solve this problem, starting from autologous native vessels to artificial vascular grafts; unfortunately, none of these have provided the perfect vascular substitute. All have been burdened by various complications, including infection, thrombogenicity, calcification, foreign body reaction, lack of growth potential, late stenosis and occlusion from intimal hyperplasia, and pseudoaneurysm formation. In the last few years, vascular tissue engineering has emerged as one of the most promising approaches for producing …

In vitro methodologies to evaluate biocompatibility: status quo and perspective

2005

Abstract The increasing use of biomaterials in clinical medicine to augment or replace failing organ function has heightened the need to apply relevant test systems to study the safety and efficacy of new medical devices. This becomes all the more important as the field of "tissue engineering" develops, in which the aim is to reconstruct tissue and organ function, for example, by using the patient's own cells seeded on to a three-dimensional (3-D) scaffold structure. In the biomaterial research field, there has been a necessary expansion of the concept of biocompatibility to address not only the biosafety issue, that is, the exclusion of cytotoxic and other deleterious effects of biomateria…