Smart polyaniline nanoparticles with thermal and photothermal sensitivity

C. A. BARBERO; S. BONGIOVANNI ABEL; M.A. MOLINA; E.I. YSLAS; C. R. RIVAROLA; M. J. KOGAN; M. C. MIRAS

Congreso; Frontiers in Polymer Science; 2015

Different methods for the synthesis of conducting polymer (polyaniline (PANI)) nanoparticles colloids are investigated. Among them: i) in-situ oxidative polymerization (ISOP) of aniline in the presence of polymeric stabilizers;[1] ii) solvent displacement (SD) from PANI solutions in N-methylpyrrolidone in the presence of polymeric stabilizers and iii) loading of polymeric hydrogel nanoparticles with PANI. In the latter case, polymeric hydrogel nanoparticles were synthesized in solution by controlled nucleation-growth process.[2] The nanoparticles are characterized by dynamic light scattering, turbidimetry, transmission electron microscopy and UV-visible spectroscopy. The size of the nanoparticles could be controlled by the nature of the polymeric stabilizer (ISOP) and/or the ratio of good/poor solvent and stabilizer concentration (SD). The polymer loading of preformed hydrogel nanoparticles could be made by ISOP or SD of PANI inside the particles. Using as polymeric stabilizers or hydrogel materials which suffer conformational changes due to thermal changes, (poly(N-isopropylacrylamide), [3] hidroxypropylcellullose) the nanoparticle dispersions become thermosensitive and aggregate upon heating. Illumination of polyaniline colloids with a near infrared laser (780 nm) also induces aggregation. The light absorbed by the polyaniline core heats up the particles inducing the conformational change of the polymeric stabilizers and triggering the aggregation. Since PANI is a conducting polymer, the same effect can be obtained by irradiation with microwaves. The biocompatibility of PANI nanoparticles is also evaluated for their application in photothermal tumor therapy.[4] References [1] S. Fedorova, J.Stejskal, Langmuir, 18 (2002)5630?5632, [2] M A Molina, C R Rivarola, M C Miras, D Lescano, C.A. Barbero, Nanotechnology 22 (2011) 245-253 [3] R. Cruz-Silva, L. Arizmendi, M. Del-Angel, J. Romero-Garcia, Langmuir, 23(2007)8?12. [4] L.E. Ibarra, E.I. Yslas, M.A. Molina, C.R. Rivarola, S. Romanini, C.A. Barbero, V.A. Rivarola, M.L. Bertuzzi, Laser Phys. 23 (2013) 066004