Search results for "Esters"
showing 10 items of 305 documents
Microstructural manipulation of electrospun scaffolds for specific bending stiffness for heart valve tissue engineering
2012
Biodegradable thermoplastic elastomers are attractive for application in cardiovascular tissue construct development due to their amenability to a wide range of physical property tuning. For heart valve leaflets, while low flexural stiffness is a key design feature, control of this parameter has been largely neglected in the scaffold literature where electrospinning is being utilized. This study evaluated the effect of processing variables and secondary fiber populations on the microstructure, tensile and bending mechanics of electrospun biodegradable polyurethane scaffolds for heart valve tissue engineering. Scaffolds were fabricated from poly(ester urethane) urea (PEUU) and the deposition…
Polyaspartamide-polylactide electrospun scaffolds for potential topical release of Ibuprofen.
2012
In this work, the production and characterization of electrospun scaffolds of the copolymer α,β-poly(N-2-hydroxyethyl)-DL-aspartamide-graft-polylactic acid (PHEA-g-PLA), proposed for a potential topical release of Ibuprofen (IBU), are reported. The drug has been chemically linked to PHEA-g-PLA and/or physically mixed to the copolymer before electrospinning. Degradation studies have been performed as a function of time in Dulbecco phosphate buffer solution pH 7.4, for both unloaded and drug-loaded scaffolds. By using an appropriate ratio between drug physically blended to the copolymer and drug-copolymer conjugate, a useful control of its release can be obtained. MTS assay on human dermal fi…
Integration of PCL and PLA in a monolithic porous scaffold for interface tissue engineering.
2016
A novel bi-layered multiphasic scaffold (BLS) have been fabricated for the first time by combining melt mixing, compression molding and particulate leaching. One layer has been composed by polylactic acid (PLA) presenting pore size in the range of 90-110µm while the other layer has been made of polycaprolactone (PCL) with pores ranging from 5 to 40µm. The different chemo-physical properties of the two biopolymers combined with the tunable pore architecture permitted to realize monolithic functionally graded scaffolds engineered to be potentially used for interface tissues regenerations. BLS have been characterized from a morphological and a mechanical point of view. In particular, mechanica…
Electrospun Polyhydroxyethyl-Aspartamide-Polylactic Acid Scaffold for Biliary Duct Repair: A Preliminary In Vivo Evaluation
2017
Abstract Tissue engineering has emerged as a new approach with the potential to overcome the limitations of traditional therapies. The objective of this study was to test whether our polymeric scaffold is able to resist the corrosive action of bile and to support a cell's infiltration and neoangiogenesis with the aim of using it as a biodegradable tissue substitute for serious bile duct injuries. In particular, a resorbable electrospun polyhydroxyethyl-aspartamide–polylactic acid (90 mol% PHEA, 10 mol% PLA)/polycaprolactone (50:50 w/w) plate scaffold was implanted into rabbit gallbladder to assess the in vivo effects of the lytic action of the bile on the scaffold structure and then as a tu…
Synthesis, characterization and foaming of PHEA-PLLA, a new graft copolymer for biomedical engineering
2014
Abstract In this study a chemical grafting procedure was set up in order to link high molecular weight poly L-lactic acid (PLLA) chains to the hydrophilic α,β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) backbone. A graft copolymer named PHEA-g-PLLA (or simply PHEA–PLLA) was obtained bearing a degree of derivatization of 1.0 mol.% of PLLA as grafted chain. This new hybrid derivative offers both the opportune crystallinity necessary for the production of scaffolds trough a thermally induced phase separation (TIPS) technique and the proper chemical reactivity to perform further functionalizations with bio-effectors and drugs. PHEA–PLLA porous scaffolds for tissue engineering applications were…
Modulation of physical and biological properties of a composite PLLA and polyaspartamide derivative obtained via thermally induced phase separation (…
2016
Abstract In the present study, blend of poly l -lactic acid (PLLA) with a graft copolymer based on α,β-poly(N-hydroxyethyl)- dl -aspartamide and PLA named PHEA-PLA, has been used to design porous scaffold by using Thermally Induced Phase Separation (TIPS) technique. Starting from a homogeneous ternary solution of polymers, dioxane and deionised water, PLLA/PHEA-PLA porous foams have been produced by varying the polymers concentration and de-mixing temperature in metastable region. Results have shown that scaffolds prepared with a polymer concentration of 4% and de-mixing temperature of 22.5 °C are the best among those assessed, due to their optimal pore size and interconnection. SEM and DSC…
Production of a Double-Layer Scaffold for the “On-Demand” Release of Fibroblast-like Limbal Stem Cells
2019
The production and characterization of a double layer scaffold, to be used as a system for the “on demand” release of corneal limbal stem cells are here reported. The devices used in the clinics and proposed so far in the scientific literature, for the release of corneal stem cells in the treatment of limbal stem cell deficiency, cannot control the in vivo space-time release of cells since the biomaterial of which they are composed is devoid of stimuli responsiveness features. Our approach was to produce a scaffold composed of two different polymeric layers that give the device the appropriate mechanical properties to be placed on the ocular surface and the possibility of releasing the stem…
Polylactide-based materials science strategies to improve tissue-material interface without the use of growth factors or other biological molecules
2018
In a large number of medical devices, a key feature of a biomaterial is the ability to successfully bond to living tissues by means of engineered mechanisms such as the enhancement of biomineralization on a bone tissue engineering scaffold or the mimicking of the natural structure of the extracellular matrix (ECM). This ability is commonly referred to as "bioactivity". Materials sciences started to grow interest in it since the development of bioactive glasses by Larry Hench five decades ago. As the main goal in applications of biomedical devices and tissue scaffolds is to obtain a seamless tissue-material interface, achieving optimal bioactivity is essential for the success of most biomate…
Characterization of the complete fiber network topology of planar fibrous tissues and scaffolds
2010
Understanding how engineered tissue scaffold architecture affects cell morphology, metabolism, phenotypic expression, as well as predicting material mechanical behavior has recently received increased attention. In the present study, an image-based analysis approach that provides an automated tool to characterize engineered tissue fiber network topology is presented. Micro-architectural features that fully defined fiber network topology were detected and quantified, which include fiber orientation, connectivity, intersection spatial density, and diameter. Algorithm performance was tested using scanning electron microscopy (SEM) images of electrospun poly(ester urethane)urea (ES-PEUU) scaffo…
Photocrosslinkable polyaspartamide/polylactide copolymer and its porous scaffolds for chondrocytes
2017
With the aim to produce, by a simple and reproducible technique, porous scaffolds potentially employable for tissue engineering purposes, in this work, we have synthesized a methacrylate (MA) copolymer of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) and polylactic acid (PLA). PHEA-PLA-MA has been dissolved in organic solvent at different concentrations in the presence of NaCl particles with different granulometry, and through UV irradiation and further salt leaching technique, various porous scaffolds have been prepared. Obtained samples have been characterized by scanning electron microscopy and their porosity has been evaluated as well as their degradation profile in aqueous medium in…