Nanofibrous scaffolds containing conductive nanoparticles

F. MONTINI BALLARÍN; F. BUFFA; G.A. ABRAHAM

Rosario, Santa Fé, Argentina

Taller; 1º Taller de Órganos Artificiales, Biomateriales e Ingeniería de Tejidos (BIOOMAT); 2009

UNR, CAIC y SLABO

Nanofibrous polymeric scaffolds have biomimetic features and can create an extracellular matrix architecture in a nanoscale way. Recognizing the importance of electrical and mechanical properties for several tissue reconstruction, conductive nanofibrous scaffolds are interesting candidates for tissue engineering and biotechnological applications. In this work we report the development of polyurethane-based nanocomposite scaffolds with conductive properties obtained by electrospinning. Electrospun polyurethane scaffolds containing single-walled carbon nanotubes (SWCNT) or polyaniline (PANI) 0.5, 1, 1.5 and 2% wt, were prepared. Medical-grade aliphatic polyurethane (Tecoflex 60D) was dissolved in dimethylformamide. The polyurethane solutions were mixed with suspended nanoparticle in tetrahydrofuran and the mixture sonicated until complete homogenization. The content and dispersion of nanoparticles played an important role in the electrospinnability of the solutions. The processing conditions were optimized in order to obtain uniform bead-free nanofibrous membranes. The residual solvent was completely removed under vacuum and the morphology of the prepared membranes was examined by SEM. An effect in the microstructure was found,: the mean diameter of the nanofibers decreased with the increase in the nanoparticle content. For 1.5% wt SWCNT a mean diameter of 464 nm was measured, while in the case of the same concentration of PANI a 430 nm in diameter was observed. In all cases, a unimodal diameter distribution was obtained. Conductivity measurements were performed by four-probe method, and by impedance mesuarements using a LCR meter. The scaffolds showed an increase in the conductivity, both a.c and d.c. conductivity, with an increase in the nanoparticles concentration. However, with both types of composites the nanoparticle content exhibited an upper limit, above which the conductivity decreased. The scaffolds containing polyaniline nanotubes presented significant higher conductivity values. Further studies on the nanoparticle dispersion-aggregation in the nanofiber and nanofiber roughness are under progress.