Search results for " PLLA"

Sterilization of macroscopic poly(l-lactic acid) porous scaffolds withdense carbon dioxide: Investigation of the spatial penetration of thetreatment …

2016

Abstract In this work the sterilization with dense carbon dioxide of poly( l -lactic acid) (PLLA) porous scaffolds intended for tissue engineering applications was investigated with the main objective of confirming the three-dimensional efficacy of the treatment and of analysing the scaffold properties after CO2 treatment. For this purpose the scaffold was contaminated with a conventional bacterium (Escherichia coli) and with spores (Streptomyces coelicolor), a species more fascinating and difficult to inactivate. Contamination was performed in such a way to soak the whole matrix with bacteria and spores. The effect of pressure and treatment time on the efficacy of the sterilization was eva…

In vitro bioactivity study of composite scaffold prepared via thermally induced phase separation

Among porous materials suitable for Bone Tissue Engineering (BTE) scaffolds, bioactive ceramics (hydroxyapatite, HA) and bioactive glasses (BG) have been used for their excellent biocompatibility, bioactivity and efficient osteointegration (1). However, their major limitations are brittleness, low mechanical stability and low dissolution rate (2). Recent evidences suggest that composite scaffold based on biodegradable polymers (e.g. Poly-lacticacid (PLLA)) simultaneously loaded with HA and BG hold promising potential as efficient osteoconductive implants (3, 4). In this work we investigated the possibility to produce composite PLLA-HA-BG scaffolds via Thermally Induced Phase Separation (TIP…

BIOGLASS® integration in Poly-L-Lactic-Acid scaffolds produced via Thermally Induced Phase Separation (TIPS).

In this work, a method of integration of BG particles in polymeric scaffold was developed with a trial and error procedure. The main purpose was to obtain highly porous and mechanically stable bioactive devices.

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…

Characterization of PLLA scaffolds for biomedical applications

2017

The porosity and pore size distribution of three-dimensional scaffolds have direct implications on their biomedical applications (tissue engineering, drug delivery, and wound dressing). Accordingly, in this paper, a fast, facile, and conservative method relying on low-field nuclear magnetic resonance (LF-NMR) for the evaluation of mean pore size and pore size distribution of polymeric scaffolds is reported. The applicability of the technique is demonstrated on poly-L-lactic acid scaffolds fabricated using the thermal induced phase separation. Results obtained through LF-NMR are successfully compared to scanning electron microscope and X-ray microcomputed tomography micrographs.

POROUS SCAFFOLDS BASED ON PLLA/FUNCTIONALISED POLYMERS BLENDS PRODUCED BY THERMALLY INDUCED PHASE SEPARATION

2014

Tubular composite scaffolds produced via Diffusion Induced Phase Separation (DIPS) as a shaping strategy for anterior cruciate ligaments reconstructi…

Injuries of tendons and ligaments are common, especially among the young population. Anterior cruciate ligament (ACL) injuries do not heal due to its limited vascularization and hence, surgical intervention is usually required. The ideal scaffold for ligament tissue engineering (TE) should be biocompatible and possess mechanical and functional characteristics comparable to the native ACL. The Diffusion Induced Phase Separation (DIPS) technique allows the preparation of homogenous porous tubular scaffold with micro-pores using a rather simple procedure. Composites based on biodegradable polymers and bioglass have attracted much attention in tissue reconstruction and repair because of their b…

Biological characterization of Poly-L-lactic acid (PLLA)/Hydroxyapatite (HA)/Bioglass (BG) composite scaffolds made by Thermally Induced Phase Separa…

In the last few years, Tissue Engineering has focused on the favourable effects that composite scaffolds have on cell adhesion, growth and differentiation. In fact, composite scaffolds, usually composed of a synthetic polymer supplemented with naturally occurring components, display superior mechanical properties and bioconductivity than scaffolds consisting of a single component. Hydroxyapatite (HA) is the major inorganic component of bones. Bioglass (BG) is known to exert stimulatory effects on cells by ion release and hence, could be also advantageous for Bone Tissue Engineering. Poly-L-lactic acid (PLLA) is a versatile synthetic polymer combinable with HA and BG. The aim of this work wa…

Tubular scaffold for vascular tissue engineering application

2010

A critical obstacle in tissue engineering is the inability to maintain large masses of living cells upon transfer from the in vitro culture conditions into the host in vivo. Capillaries, and the vascular system, are required to supply essential nutrients, including oxygen, remove waste products and provide a biochemical communication “highway”. Another goal in this research field is the possibility to tune the biodegradability of the scaffold. After implantation, the scaffold has to be gradually replaced by cells and extra cellular matrix and it is crucial that this replacement takes place with an appropriate dynamics. A premature degradation, in fact, could lead to a collapse of the struct…

PLLA-BASED SCAFFOLDS FOR OSTEOCHONDRAL TISSUE REGENERATION VIA THERMALLY INDUCED PHASE SEPARATION TECHNIQUE

L’ingegneria tessutale (TE) è una scienza multidisciplinare che mira a progettare e sviluppare sostituti biologici per migliorare, riparare e/o sostituire i tessuti negli organismi umani. Sulla base della tipica triade dell’ingegneria tessutale è incentrato il primo capitolo Scaffold, Source and Signal; lo scaffold funge da struttura tridimensionale, le cellule rappresentano la source mentre il bioreattore fornisce gli adeguati segnali chimico/fisici. In questo lavoro di tesi sono stati presi in considerazione tutti e tre questi aspetti avendo come obiettivo la rigenerazione osteocondrale. La guarigione dei difetti osteocondrali, riguardanti le lesioni della cartilagine che si esten- dono f…