Preparation and characterization of nanoparticles using poly(N-isopropylacrylamide)-poly(ε-caprolactone) and poly(ethylene glycol)-poly(ε-caprolactone) block copolymers with thermosensitive function

Abstract

Thermosensitive nanoparticles were prepared via the self-assembly of two different poly(ε-caprolactone)-based block copolymers of poly(N-isopropylacrylamide)-b-poly(ε-caprolactone) (PNPCL) and poly(ethylene glycol)-b-poly(ε-caprolactone) (PEGCL). The self-aggregation and thermosensitive behaviors of the mixed nanoparticles were investigated using 1 H-NMR, turbidimetry, differential scanning microcalorimetry (micro-DSC), dynamic light scattering (DLS), and fluorescence spectroscopy. The copolymer mixtures (mixed nanoparticles, M1-M5, with different PNPCL content) formed nano-sized self-aggregates in an aqueous environment via the intra-and/ or intermolecular association of hydrophobic PCL chains. The microscopic investigation of the mixed nanoparticles showed that the critical aggregation concentration (cac), the partition equilibrium constants (K v ) of pyrene, and the aggregation number of PCL chains per one hydrophobic microdomain varied in accordance with the compositions of the mixed nanoparticles. Furthermore, the PNPCL harboring mixed nanoparticles evidenced phase transition behavior, originated by coil to the globule transition of PNiPAAm block upon heating, thereby resulting in the turbidity change, endothermic heat exchange, and particle size reduction upon heating. The drug release tests showed that the formation of the thermosensitive hydrogel layer enhanced the sustained drug release patterns by functioning as an additional diffusion barrier.

Versatile strategies for fabricating polymer nanomaterials with controlled size and morphology

“…[43][44][45][46][47] Block copolymer amphiphiles self-assemble to organize block copolymer micelles or vesicles, which may then be chemically transformed into crosslinked spherical nanostructures. Generally, this strategy allows the size control of nanoparticles with tuning the block length and ratio of the copolymers.…”

Formation of poly(ethylene glycol)-poly(ε-caprolactone) Nanoparticles via Nanoprecipitation

“…[21][22][23] A great deal of different strategies for modification of these polymeric materials has been also intensively reported with the aim of fine-tuning of physicochemical properties on demand for practical applications by means of (i) chemically conjugation through copolymerization with poly(ethylene glycol) (PEG) [24][25][26][27] or biologically benign moieties, [28][29][30][31] and (ii) surface modification via surface coating, [32][33][34] blend, 35,36 and plasma treatment. 37 Those modifications make it possible to readily tailor the hydrophilicity, 32,35 specific interaction, 32,37 and other desired functions.…”

“…37 Those modifications make it possible to readily tailor the hydrophilicity, 32,35 specific interaction, 32,37 and other desired functions. 24,26,27 Specifically, block copolymer of polyester with featured components facilitates colloidal drug delivery carrier to be highly efficient in sustained release on specific target site. Colloidal carriers of polyester copolymer incorporated with PEG exhibit superior biodistribution by prolonged circulation in blood system because the mobile PEG brush serves as a protective shield around the particulate, significantly suppressing undesired adsorption of blood proteins onto therapeutic particulate.…”

Synthesis and characterization of thermosensitive nanoparticles based on PNIPAAm core and chitosan shell structure

“…[8][9][10][11]et al reported the synthesis of PNIPAAm-chitosan complex particles with the method of soap less dispersion polymerization. 12,13 In this reaction system, the chitosan behaved as a *Corresponding Author.…”