INVESTIGADORES
ABRAHAM gustavo Abel
congresos y reuniones científicas
Título:
Electrospun scaffolds of segmented polyurethanes based on PEG-PLLA-PTMC
Autor/es:
R.B. TRINCA; M.I. FELISBERTI; G.A. ABRAHAM
Lugar:
Rosario
Reunión:
Congreso; VIII Congreso Latinoamericano de Órganos Artificiales, Biomateriales e Ingeniería de Tejidos (VIII COLAOB); 2014
Institución organizadora:
SLABO
Resumen:
Polyurethanes
(PU) are an important and versatile class of polymers characterized by a broad
spectrum of compositions, molecular architectures, properties and applications.
The chemical nature, structure and content of diisocyanates, polyols and chain
extenders allow controlling the PU properties. By choosing all bifunctional compounds,
linear block copolymers, named segmented polyurethanes (SPU), are obtained.
A
set of SPU based on low-molecular mass (2 kDa) poly(ethylene glycol) (PEG),
poly(l-lactide) (PLLA) and poly(trimethylene carbonate) (PTMC), was synthesized.
PLLA and PTMC homopolymers were obtained by ring-opening polymerization (ROP)
from l-lactide and trimethylene carbonate monomers, using 1,4-butanediol as
initiator. For SPU synthesis, a single vessel methodology with two reaction
steps was adopted, a pre-polymer synthesis using 1,6-hexane diisocyanate followed
by a pre-polymer extension using 1,4-butanediol. All SPU were characterized in
terms of thermal and mechanical properties, composition and morphology.
A
wide range of compositions (between PEG, PLLA and PTMC) were investigated.
Mechanical and thermal properties, as well as swelling degree, are shown to be
directly related to the composition for all bi- and tri- component SPU. PLLA
takes the major contribution in means of dimensional stability and mechanical
properties, PTMC content lead to elastomeric behavior and enhance of mechanical
properties, while PEG is responsible for
the hydrophilicity of SPU, which are
related to mechanisms of cell adhesion.
Selected
formulations of SPU (e.g. 10 % PEG, 60 % PLLA and 30 % PTMC, SPU-10-60-30) were
subjected to electrospinning processing seeking the obtaining of fibrous scaffolds
for tissue engineering applications. A typical electrospinning setup consisting
of a high-voltage power supply, a single nozzle and a static flat collector,
was used. Electrospun micro/nanofibrous structures with fiber diameter ranging
from 650 nm to up micrometric dimensions were obtained by varying the applied
voltage, needle tip-to-collector distance and flow rate. Mechanical and thermal
properties shown to be dependent on either the SPU films were obtained by solvent
cast or electrospinning, glass transition relaxation events of electrospun or
solvent casted films of the SPU-10-60-30 presents no significant variation in
meanings of temperature range, while the magnitude of such transitions present
some level of variation. In mechanical meanings, electrospun films are softer
and show an elastomeric behavior and stretching recovery. In order to study the
influence of the nanofibrous surface on cell adhesion and proliferation, cell
viability assays are under progress.