Radiation synthesis of PNIPAM/montmorillonite …

AB - Novel hydrogels composed of thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) and redox-responsive poly(ferrocenylsilane) (PFS) macromolecules were formed by photopolymerization. PFS chains bearing acrylate side groups were copolymerized with NIPAM and N,N′-methylenebisacrylamide in tetrahydrofuran in a predetermined ratio under ultraviolet light-emitting diode (UV-LED) irradiation at a wavelength of 365 nm, in the presence of a photoinitiator. Crosslinking occurred smoothly, providing homogeneous hydrogels. The equilibrium swelling ratio, rheology and morphology of these hybrid PNIPAM–PFS-based hydrogels were investigated. The thermo-responsive properties of the hydrogels were studied as a function of the PFS oxidation state. In situ fabrication of silver nanoparticles inside the hydrogel network via reduction of silver nitrate by the PFS chains led to hydrogel composites. These composites showed strong antimicrobial activity while maintaining a high biocompatibility with cells

20/12/2017 · Radiation synthesis of PNIPAM ..

Reducibly degradable hydrogels of PNIPAM and PDMAEMA: Synthesis, stimulus-response and drug release

the synthesis of magnetic PNIPAM has ..

In the present study we report a facile and reproducible method of preparing magnetic thermosensitive hybrid material based on P(NIPAM) microgels covered with γ-Fe2O3 nanoparticles of 6-nm size. The iron oxide nanoparticles provided magnetic response to the microgels. In addition, the presence of the magnetic nanoparticles on the microgels altered their swelling behavior and shifted their volume phase transition temperature to higher values. In particular, for inorganic shells with 18% (w/w) of magnetic nanoparticles the volume phase transition of the microgels was shifted from 36 to 40 °C. In contrast, for shells consisting of 38% (w/w) magnetic nanoparticles the volume phase transition of the microgels was almost blocked, thus indicating that the microgel thermal response was strongly affected by the presence of the inorganic nanoparticles. The synthesized thermosensitive magnetic microgels are envisaged to be ideal for potential applications as thermosensitive targeted drug delivery systems.

PNIPAM hydrogel is a typically temperature-sensitive ..

Poly(-isopropylacrylamide) (PNIPAM) hydrogel microcapsules having a hydrophobic corona (MCs) were prepared by precipitation−polymerization performed in water-in-oil emulsion using polyethyleneoxide−polyisoprene block copolymer as macromolecular surfactant and a corona-forming compound. The resulting hydrogel MCs form stable dispersions even in highly apolar organic solvents, such as cyclohexane, but flocculate in water. An approach to load the MCs with water, based on addition of aqueous solutions to the dispersion of the MCs in THF followed by addition of apolar solvents to induce segregation of a water-rich phase, was developed. The water-filled hydrogel MCs show a well-pronounced swelling/deswelling transition triggered by temperature in an environment that contains only minute amounts of water. Encapsulating capabilities of the MCs were also demonstrated. The MCs can be envisaged for applications that require controlled dispersion and release of hydrophilic species in oils.

T1 - Poly(N-isopropylacrylamide)–poly(ferrocenylsilane) dual-responsive hydrogels: synthesis, characterization and antimicrobial applications

responsive PNIPAM nanocomposite hydrogel …

We have recently developed a set of cytocompatible hydrogels with thermoreversible properties by grafting poly(N-isopropylacrylamide) on a hyaluronan backbone (HA-pNIPAM) []. For NPC, the expression of the appropriate phenotype is a further fundamental requirement to assure the generation of an extracellular matrix that meets the specific mechanical demands of the tissue. The material is, therefore, expected to promote both re-differentiation of in vitro expanded NPC and activation of endogenous cells upon injection into the disc.

was encapsulated within n-isopropyl acrylamide hydrogel (PNIPAM) ..

Cytocompatibility (WST-1 assay), viability (trypan blue), morphology (toluidine blue), sulphated glycosaminoglycan synthesis (DMMB assay) and gene expression profile (real-time PCR) of bovine NPC cultured in HA-pNIPAM were followed for 1 week and compared to alginate gel bead cultures. The injectability and cell survival in a whole disc organ culture model were assessed up to day 7.

Poly(N-isopropylacrylamide) - Wikipedia

In this study, we tested the cytocompatibility of HA-pNIPAM hydrogels and their degradation products to NPC, as well as the viability and morphology of NPC cultured in the thermoreversible hydrogel beads in vitro. Furthermore, glycosaminoglycan production and gene profile of NPC encapsulated in HA-pNIPAM were compared to a standard three-dimensional alginate hydrogel culture. Finally, the injectability and cell survival of NPC embedded in the optimized thermoreversible hydrogel were assessed in a whole organ culture model. Overall, our results confirm the feasibility of this thermoresponsive hyaluronan gel formulation for IVD regenerative therapy.