Smart pillar[5]arene-based PDMAEMA/PES beads for selective dye pollutants removal: design, synthesis, chemical-physical characterization, and adsorption kinetic studies

This article reports on the synthesis of an innovative smart polymer, P5-QPDMAEMA, opportunely developed with the aim of combining the responsiveness of PDMAEMA polymer and the host-guest properties of covalently linked pillar[5]arenes. Thanks to a traditional Non-Induced Phase Separation (NIPS) process performed at various coagulation pH, the blending of P5-QPDMAEMA with polyethersulfone gave rise to the formation of functional beads for the removal of organic dyes in water. Adsorption tests are carried out on all the produced blend-based beads by employing two representative dyes, the cationic methylene blue (MB), and the anionic methyl orange (MO). In particular, the P5-QPDMAEMA based beads, prepared at acidic pH, featured the best MO removal rate (i. e., 91.3 % after 150 minutes starting from a 20 mg ⋅ L-1 solution) and a high selectivity towards the removal of the selected anionic dye. Based on the adsorption kinetics and isotherm calculations, the pseudo-first order and Freundlich models were shown to be the most suitable to describe the MO adsorption behavior, achieving a maximum adsorption capacity of 21.54 mg ⋅ g-1. Furthermore, zwitterionic beads are obtained by a post-functionalization of the PDMAEMA and the P5-QPDMAEMA based beads, to test their removal capability towards both anionic and cationic dyes, as shown.

pH-responsive release of chlorhexidine from modified nanoporous silica nanoparticles for dental applications

A pH-sensitive stimulus-response system for controlled drug release was prepared by modifying nanoporous silica nanoparticles (NPSNPs) with poly(4-vinylpyridine) using a bismaleimide as linker. At physiological pH values, the polymer serves as gate keeper blocking the pore openings to prevent the release of cargo molecules. At acidic pH values as they can occur during a bacterial infection, the polymer strains become protonated and straighten up due to electrostatic repulsion. The pores are opened and the cargo is released. The drug chlorhexidine was loaded into the pores because of its excellent antibacterial properties and low tendency to form resistances. The release was performed in PBS and diluted hydrochloric acid, respectively. The results showed a considerably higher release in acidic media compared to neutral solvents. Reversibility of this pH-dependent release was established. In vitro tests proved good cytocompatibility of the prepared nanoparticles. Antibacterial activity tests with

Grafting of multi-sensitive PDMAEMA brushes onto carbon nanotubes by ATNRC: tunable thickening/thinning and self-assembly behaviors in aqueous solutions

Shear-induced thickening/thinning response of synthesized MWNTs-g-PDMAEMA suspensions was facially adjusted by altering the hydrophobic interaction, amount of f-PDMAEMA and grafted-chain length.

Silica nanotubes decorated by pH-responsive diblock copolymers for controlled drug release

A novel nanocontainer, which has silica nanotube (SNT) core and pH-sensitive polymer shell attaching on the exterior surface of silica nanotube, is presented in this paper. Polymer nanorods, which are conveniently fabricated though polymerization-induced self-assembly and reorganization method, are used as templates for the deposition of silica to fabricate hybrid nanorods. Calcination of as-synthesized silica hybrid nanorods leads to hollow SNTs. SNTs are functionalized with reversible addition-fragmentation chain transfer (RAFT) agent, then surface RAFT polymerization is conducted to get poly(2-(diethylamino)ethyl methacrylate)-b-poly(oligo(ethylene glycol) methacrylate)-coated SNTs (SNT-PDEAEMA-b-POEGMA). Doxorubicin (DOX) can be encapsulated in SNT-PDEAEMA-b-POEGMA, and controlled release of loaded DOX is achieved by adjusting pH of the medium. In vitro cell viability and cellular internalization study confirm the potential application of this nanocontainer in drug and gene delivery.

Surface modification of carbon nanotubes with dendrimers or hyperbranched polymers

The different methods for modification of carbon nanotubes with dendrimers or hyperbranched polymers are summarized, and recent development is highlighted by discussing some representative examples in detail.