Search results for "tissue engineering"

Composites poly-lactic acid - hydroxyapatite scaffolds prepared via Thermally Induced Phase Separation

2013

Preparation of Poly(l-lactic acid) Scaffolds by Thermally Induced Phase Separation: Role of Thermal History

2018

Abstract Poly-L-Lactic Acid (PLLA) scaffolds for tissue engineering were prepared via thermally induced phase separation of a ternary system PLLA/dioxane/tetrahydrofurane. An extension to solution of a previously developed method for solidification from the melt was adopted, the technique being based on a Continuous Cooling Transformation (CCT) approach, consisting in recording the thermal history of rapidly cooled samples and analysing the resulting morphology. Different foams were produced by changing the thermal history, the dioxane to THF ratio (50/50, 70/30, 90/10 v/v) and the polymer concentration (2, 2.5, 4 ° wt) in the starting ternary solution. Pore size, porosity, melting and crys…

Biocompatibility evaluation of PLLA scaffolds for vascular tissue engineering

2015

Poly-L-lactic acid (PLLA), a hemicrystalline material, has been extensively studied in applications of engineered tissues, because it is biodegradable, absorbable and it supports cell attachment and growth. The purpose of this study is to evaluate tissue/ material interactions, neovascularization and the biocompatibility of PLLA by optical and scanning electron microscopy in a model of animal implant. PLLA porous disks were implanted into the dorsal subcutis of BALB/C mice for 1, 2, 3, and 8 weeks. The bioptic samples of excised PLLA and the surrounding tissue were evaluated for inflammatory response and tissue ingrowth. The samples were divided in two halves: one was fixed in neutral buffe…

Preparation and characterization of PCL/GO-g-PEG biocomposite nanofiber scaffolds

2016

Biocomposite nanofiber scaffolds of polycaprolactone (PCL) with different graphene oxide surface grafted with poly(ethylene glycol) (GO-g-PEG) concentrations were prepared by electrospinning. Morphological, mechanical as well as wettability characterization were carried out. Results showed that the average diameter of PLA/GO-g-PEG electrospun nanofibers increased by increasing the filler content. GO-g-PEG enhanced the electrospun PCL hydrophilicity as well as the Young modulus, in particular at low GO-g-PEG concentrations.

Joining Two Natural Motifs: Catechol-Containing Poly(phosphoester)s.

2017

Numerous catechol-containing polymers, including biodegradable polymers, are currently heavily discussed for modern biomaterials. However, there is no report combining poly(phosphoester)s (PPEs) with catechols. Adhesive PPEs have been prepared via acyclic diene metathesis polymerization. A novel acetal-protected catechol phosphate monomer was homo- and copolymerized with phosphoester comonomers with molecular weights up to 42000 g/mol. Quantitative release of the catechols was achieved by careful hydrolysis of the acetal groups without backbone degradation. Degradation of the PPEs under basic conditions revealed complete and statistical degradation of the phosphotri- to phosphodiesters. In …

In situ forming hydrogels of hyaluronic acid and inulin derivatives for cartilage regeneration.

2014

An in situ forming hydrogel obtained by crosslinking of amino functionalized hyaluronic acid derivatives with divinylsulfone functionalized inulin (INU-DV) has been here designed and characterized. In particular two hyaluronic acid derivatives bearing respectively a pendant ethylenediamino (EDA) portion (HA-EDA) and both EDA and octadecyl pendant groups (HA-EDA-C18) were crosslinked through an azo-Michael reaction with INU-DV. Gelation time and consumption of DV portions have been evaluated on hydrogel obtained using HA-EDA and HA-EDA-C18 derivatives with a concentration of 3% w/v and a ratio 80/20 w/w respect to the crosslinker INU-DV. The presence of pendant C18 chains improves mechanical…

Polyphosphate: A Morphogenetically Active Implant Material Serving as Metabolic Fuel for Bone Regeneration

2015

The initial mineralization centers during human bone formation onto osteoblasts are composed of CaCO3 . Those bioseeds are enzymatically formed via carbonic anhydrase(s) in close association with the cell surface of the osteoblasts. Subsequently, the bicarbonate/carbonate anions are exchanged non-enzymatically by inorganic phosphate [Pi ]. One source for the supply of Pi is polyphosphate [polyP] which is a physiological polymer, formed in the osteoblasts as well as in the platelets. The energy-rich acid anhydride bonds within the polyP chain are cleaved by phosphatase(s); during this reaction free-energy might be released that could be re-used, as metabolic fuel, for the maintenance of the …

Poly-l-Lactic Acid (PLLA)-Based Biomaterials for Regenerative Medicine: A Review on Processing and Applications

2022

Synthetic biopolymers are effective cues to replace damaged tissue in the tissue engineering (TE) field, both for in vitro and in vivo application. Among them, poly-l-lactic acid (PLLA) has been highlighted as a biomaterial with tunable mechanical properties and biodegradability that allows for the fabrication of porous scaffolds with different micro/nanostructures via various approaches. In this review, we discuss the structure of PLLA, its main properties, and the most recent advances in overcoming its hydrophobic, synthetic nature, which limits biological signaling and protein absorption. With this aim, PLLA-based scaffolds can be exposed to surface modification or combined with other bi…

Polybutylene Succinate Processing and Evaluation as a Micro Fibrous Graft for Tissue Engineering Applications

2022

A microfibrous tubular scaffold has been designed and fabricated by electrospinning using poly (1,4-butylene succinate) as biocompatible and biodegradable material. The scaffold morphology was optimized as a small diameter and micro-porous conduit, able to foster cell integration, adhesion, and growth while avoiding cell infiltration through the graft’s wall. Scaffold morphology and mechanical properties were explored and compared to those of native conduits. Scaffolds were then seeded with adult normal human dermal fibroblasts to evaluate cytocompatibility in vitro. Haemolytic effect was evaluated upon incubation with diluted whole blood. The scaffold showed no delamination, and mech…

Tailoring PLLA scaffolds for tissue engineering applications: Morphologies for 2D and 3D cell cultures

2009

PLLA scaffold suitable for dermis regeneration were realized by Thermally Induced Phase Separation (TIPS) starting from a ternary solution PLLA/dioxane/water. The reconstruction of a complex tissues as the dermis implies the use of different cellular types (coculture), with different growth behaviour (2D vs. 3D). The scaffolds present an homogeneous porous surface to allow the keratinocytes 2D growth and a porous internal structure for the fibroblasts 3D growth. Our results show that the porosity of the surface can be tuned by changing the chemical nature of the sample holder (aluminium, teflon, polypropylene). A large variety of morphologies, in terms of average pore size and interconnecti…