Hollow double-layered polymer microspheres with pH and thermo-responsive properties as nitric oxide-releasing reservoirs

Abstract

Nitric oxide (NO)-releasing hollow double-layered polymer microspheres (HDPMs) with both pH-and thermo-responsive properties in aqueous media are designed and prepared by a multistep process. Hollow double-shelled polymer microspheres with secondary amino groups are prepared by distillation precipitation copolymerization of N-isopropylacrylamide (NIPAAm) with 2-(dimethylamino) ethyl methacrylate (DMAEMA) and EGDMA in presence of SiO 2 /P(2-(ethyl(boc)amino)ethyl methacrylate (bocAmEMA)-co-EGDMA) core-shell microspheres as seeds to obtain SiO 2 /P(bocAmEMA-co-EGDMA)/P(EGDMA-co-DMAEMA-co-NIPAAm) trilayer microspheres with subsequent removal of silica core by hydrogen fluoride aqueous solution and deprotection of secondary amino groups with CF 3 CO 2 H. Hollow polymer microspheres with N-diazenuimdiolated NO donors are prepared by the reaction between secondary amino groups of hollow P(AmEMA-co-EGDMA)/P(EGDMA-co-DMAEMA-co-NIPAAm) microspheres and high pressure of NO (5.0 atm) under basic condition (CH 3 ONa). The resultant microspheres are systematically characterized by TEM, FT-IR, TGA, elemental analysis and dynamic laser scattering (DLS). The final N-diazeniumdiolated hollow double-shelled microspheres show a controlled NO release behavior dependent on pH and temperature in the environments.

Antibacterial Activity of Nitric Oxide-Releasing Hyperbranched Polyamidoamines

“…Formation of N -diazeniumdiolate NO donors were verified by the appearance of a ∼ 250 nm characteristic UV–vis peak (Figure S4). FT-IR spectra also indicated O–N–N–O deformation (1350–1370 cm –1 ) and N–N stretching (1230–1250 cm –1 ) vibrations. ,− Real-time NO release data was measured in PBS (10 mM, pH 7.4, 37 °C). As shown in Table , h-PAMAM-PO-1/NO stored the largest amount of NO (∼2.50 μmol mg –1 ), followed by h-PAMAM/NO (∼2.16 μmol mg –1 ).…”

Superparamagnetic Reduction/pH/Temperature Multistimuli-Responsive Nanoparticles for Targeted and Controlled Antitumor Drug Delivery

“…The Fe 3 O 4 @PMAA@PNIPAM nanoparticles were prepared by the two-stage distillation precipitation polymerization in the presence of Fe 3 O 4 @PMAA microspheres as seeds. ,, In a typical experiment, Fe 3 O 4 @PMAA (0.20 g), NIPAM (0.4 g, 3.5 mmol), MBA cross-linker (0.06 g, 0.39 mmol), and AIBN (0.015 g) initiator were dispersed in 80 mL of acetonitrile at room temperature in a 100 mL double-necked flask. The reaction equipment and process were the same as for the preparation of the Fe 3 O 4 @PMAA.…”

Nitric Oxide–Releasing Macromolecular Scaffolds for Antibacterial Applications

“…To achieve steady NO-release kinetics under various conditions (e.g., different pHs and temperatures), pH- and thermal-responsive segments (e.g., poly(2-(dimethylamino)ethyl methacrylate and poly-N-isopropylacrylamide) acting as environmentally protective sheaths were incorporated into the polymeric particles through a two-stage distillation precipitation polymerization. [55] The resulting N -diazeniumdiolate-modified double-layered polymeric particles exhibited nearly equivalent NO-release properties over wide pH (5–9) and temperature (20–55 °C) ranges.…”