RESUMEN

Previously uncharacterized poly(N-isopropylacrylamide-acrylamide-allylamine)-coated magnetic nanoparticles (MNPs) were synthesized using silane-coated MNPs as a template for radical polymerization of N-isopropylacrylamide, acrylamide, and allylamine. Properties of these nanoparticles such as size, biocompatibility, drug loading efficiency, and drug release kinetics were evaluated in vitro for targeted and controlled drug delivery. Spherical core-shell nanoparticles with a diameter of 100 nm showed significantly lower systemic toxicity than did bare MNPs, as well as doxorubicin encapsulation efficiency of 72%, and significantly higher doxorubicin release at 41°C compared with 37°C, demonstrating their temperature sensitivity. Released drugs were also active in destroying prostate cancer cells (JHU31). Furthermore, the nanoparticle uptake by JHU31 cells was dependent on dose and incubation time, reaching saturation at 500 µg/mL and 4 hours, respectively. In addition, magnetic resonance imaging capabilities of the particles were observed using agarose platforms containing cells incubated with nanoparticles. Future work includes investigation of targeting capability and effectiveness of these nanoparticles in vivo using animal models. FROM THE CLINICAL EDITOR: In this paper, previously uncharacterized magnetic nanoparticles were synthesized using silane-coated MNPs as a template for radical polymerization of N-isopropylacrylamide, acrylamide, and allylamine. Various properties of these nanoparticles were evaluated in vitro for targeted drug delivery.

Asunto(s)

Sistemas de Liberación de Medicamentos/métodos , Magnetismo , Nanopartículas/química , Polímeros/química , Animales , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Doxorrubicina/administración & dosificación , Doxorrubicina/química , Doxorrubicina/farmacocinética , Humanos , Masculino , Ratones , Microscopía Electrónica de Transmisión , Células 3T3 NIH , Nanopartículas/efectos adversos , Nanopartículas/ultraestructura , Polímeros/efectos adversos , Polímeros/síntesis química , Polímeros/farmacocinética

RESUMEN

The aim of this study was to develop a novel method to encapsulate magnetic nanoparticles (MNPs) with polymer via covalent bonding, in order to increase the magnetic nanoparticle stability and ease the synthesis process. In this technique, silane coated MNPs act as a template for polymerization of the monomer N-isopropylacrylamide, (NIPA) via radical polymerization. Transmission and scanning electron microscopy indicated the size of the original MNP was approximately 10 nm, the silane-coated MNP was 40 nm and the NIPA silane-coated MNP was 100 +/- 10 nm. Chemical composition and chemical state analysis of NIPA MNPs by FTIR and XPS showed that the MNPs were actually encapsulated by silane and NIPA. Furthermore, the magnetic properties of different layers on the MNP, analyzed by SQUID, indicated a decrease in saturation magnetization for each layer. The results demonstrate the feasibility of encapsulation of the MNP with NIPA by means of silane covalent bonding. Future work will investigate the phase transition and biocompatibility properties of the NIPA-coated MNP for drug delivery and tissue engineering applications.