PCL-HA composites functionalized with silver nanoparticles by supercritical CO2 for biomedical applications

LEONARDI, AGUSTINA B.A,*, DELL`ERBA IGNACIO E.A , JAEGER, PHILIPB , FANOVICH, M. ALEJANDRAA

Campinhas

Congreso; International Conference on Supercritical Fluids; 2019

PROSCIBA

Polycaprolactone (PCL) is a biodegradable and biocompatible semi-crystalline polyester and hydroxyapatite (HA) is the most frequently used calcium phosphate in bone tissue repair. Due to their individual properties, the combination of PCL and HA have a great potential for fabrication of functionalized scaffolds with silver nanoparticles (AgNPs). This composition (PCL/HA/AgNPs) can be designed to give rise to an antibacterial support with nano and micrometric structuring of great utility in the area of tissue engineering. Thus, it is possible to introduce new functionalities during PCL/HA composites processing with the help of supercritical carbon dioxide (scCO2).In this work, two approaches were carried out to disperse the AgNPs into poweredcomposite of PCL with 5 and 10%w/w of HA. One procedure (W1) consisted of mixedthe silver nanoparticles precursors (silver salt, glycerol and amino silane) with the corresponding amount of powered composite. In the other way (W2), the AgNPs were synthesized previously, and the resulted suspension mixed with the powered composite. The foaming process was carried out at 40ºC and 170bar in a high-pressure unit (Eurotechnica GmbH, Germany). The saturation time was 4 hour and after that, the pressure was released according to previous foaming studies.The samples were characterized by UV spectroscopy of solids, Scanning ElectronicMicroscopy (SEM), density and antibacterial assays. The photothermal effect of the scaffolds was measured using a 532 nm laser (Power close to 2W/cm2). The amount of AgNPs was determined by thermogravimetric analysis. Microstructural analyses from SEM images were made by using imageJ software tool.The materials obtained with the W1 method showed a homogeneous distribution of the AgNPsin comparison with the W2 method. The obtained scaffolds show a global porosity close to 80%, and an average pore size of 100 µm. The photothermal effect allowed an increase of 25ºC under 200 second of irradiation.