Shell cross-linked stimuli-responsive micelles as vehicles for biomedical applications

Conference (2012, November 16)

Stimuli-responsive magnetic nanohybrids designed for controlled drug release application

Conference (2012, May 10)

Stimuli-responsive organic/inorganic nanohybrids, with an inorganic core and a polymer coating, have been frequently suggested as a promising vehicle for drug or gene delivery and also controlled release ... [more ▼]

Stimuli-responsive organic/inorganic nanohybrids, with an inorganic core and a polymer coating, have been frequently suggested as a promising vehicle for drug or gene delivery and also controlled release, due to their outstanding biocompatibility, versatile surface modification, specific responsive properties to external stimuli, and so on. Magnetic nanoparticles have various applications in biomedical filed, such as magnetic resonance imaging, biosensors, magnetic separation, drug release, hyperthermia therapy and so on. Poly (acrylic acid) copolymers exhibit a sharp conformation transition when exposed to external change in pH. The PAA copolymer was used to form a polymer shell outside the magnetic core, a cationic dye was uploaded by electro-static interaction. The controlled release was achieved by tuning the external pH value. Magnetic/SiO2 mesoporous nanoparticles were prepared as another drug vehicle, in order to obtain a higher drug loading amount. Crystalline molecules were utilized as a gate keeper to control the release of drugs uploaded. [less ▲]

Stabilization of gold nanoparticles by thermo-responsive poly (vinyl alcohol)-b-poly (N-vinylcaprolactam) copolymers

Poster (2011, November 21)

Stimuli-responsive nano-materials have been playing increasingly important roles in the biomedical field due to their ability to alter the physico-chemical properties in response to external stimuli, such ... [more ▼]

Stimuli-responsive nano-materials have been playing increasingly important roles in the biomedical field due to their ability to alter the physico-chemical properties in response to external stimuli, such as temperature, pH, ionic strength, magnetic field, etc. Nanohybrids bearing an inorganic core and thermo-responsive polymer shell are particularly applicable in target delivery and controlled drug release. Poly (N-vinylcaprolactam) (PNVCL) and its copolymers, exhibiting lower critical solution temperature (LCST) where the transition between hydrophilic and hydrophobic state happens, is one of the optimal choices for this core/shell structure. Here we present the in-situ fabrication of thermo-responsive gold nanohybrids coated with a novel poly(vinyl alcohol)-b-poly(N-vinylcaprolactam) (PVOH-b-PNVCL) block copolymer prepared by the cobalt-mediated radical polymerization (CMRP). The interaction between both PVOH and PNVCL segments and gold nanoparticles was confirmed by FT-IR spectra. A sharp thermo-induced phase transition with a good reversibility upon change in temperature was detected by DLS and UV/vis spectrometer. Furthermore, the presence of hydrophilic PVOH moieties endows the gold nanohybrids with improved colloidal stability above LCST without any flocculation detected, compared with the gold nanoparticles stabilized with PNVCL homopolymer. This kind of gold nanohybrids can be envisaged as a new drug delivery vehicle. [less ▲]

Preparation and characterization of thermoresponsive gold nanohybrids

Poster (2011, April 29)

Magnetic nanoparticles coated by temperature responsive copolymers for hyperthermia

in Journal of Materials Chemistry (2008), 18(28), 3352-3360

Various temperature-responsive N-isopropylacrylamide-based functional copolymers were prepared and used for the stabilization of iron oxide nanoparticles. The copolymers investigated are poly(acrylic acid ... [more ▼]

Various temperature-responsive N-isopropylacrylamide-based functional copolymers were prepared and used for the stabilization of iron oxide nanoparticles. The copolymers investigated are poly(acrylic acid)-b-poly(N-isopropylacrylamide) (PAA-PNIPAM) and poly(acrylic acid)-b-poly(N-isopropylacrylamide)-b-poly(acrylate methoxy poly(ethylene oxide)) (PAA-PNIPAM-PAMPEO), with different molecular weights. The coated nanoparticles were characterized in terms of size by a combination of dynamic light scattering (DLS) and transmission electron microscopy (TEM). A sharp temperature transition was confirmed by particle size measurements vs. temperature. In addition, the stealthiness of the coated nanoparticles has been assessed in vitro by the haemolytic CH50 test. These measurements evidenced the crucial role of the PEO segments on the stealthiness of the nanoparticles and thus that such copolymers are particularly suitable for biomedical applications. Preliminary experiments of alternating magnetic field induced heating were performed and specific absorption rates of the various samples were recorded. [less ▲]