Electroactivity and stability of polylactide/polypyrrole composites.
Electrically conductive biodegradable composites are useful in biomedical engineering to mediate electrical interactions between cells and electrical components. Because conductive polymers are often subjected to progressive oxidative deterioration and dedoping, their electrical stability in aqueous environment is, therefore, critical. We used cyclic voltammetry (CV) to investigate the electroactivity and stability of conductive membranes made of only 5% conductive polypyrrole (PPy) particles blended with 95% insulating polylactide (PLLA). During 1000 CV scans, the electroactivity of the composite membranes revealed a period of initial activation, followed by a relatively stable period and subsequent slow deterioration process. PPy membranes doped with heparin, a cell-adhesive polysaccharide and polyanion, displayed electrical stability superior to that of PPy membranes doped with chlorine anions. The latter, however, recorded a higher initial electroactivity during the first ca. 150 scans. XPS analysis showed that the deterioration of the electroactivity was likely due to the oxidation of the PPy. ATR-FT-IR and SEM were also used to characterize the materials. The PLLA/PPy membranes were thus electroactive and maximum electroactivity was achieved through an activation process. The heparin-doped PPy composite was electrically stable and may, thus, be used for multiple long-term electrical stimulations.
Département de Chirurgie, Faculté de Médecine, Université Laval, Centre de Recherche Hôpital Saint-François d'Assise, CHUQ, 10 rue de l'Espinay, local E0-165, Québec, QC, Canada G1L 3L5.
Linli
L
Zhang
Shiyun
S
Meng
Ze
Z
Zhang
D004553:Electric Conductivity; D006493:Heparin / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D023822:Tissue Engineering / Q000379:methods
D011091:Polyesters; D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; C033616:poly(lactide); D006493:Heparin