Dynamic Nitroxide Functional Materials

Abstract

A substrate‐independent and versatile coating platform for (spatially resolved) surface functionalization, based on nitroxide radical coupling (NRC) reactions and the formation of thermo‐labile alkoxyamine functional groups, was introduced. Nitroxide‐decorated poly(glycidyl methacrylate) (PGMA) microspheres, obtained through bioinspired copolymer surface deposition using dopamine and a nitroxide functional dopamine derivative as monomers, were conjugated with small functional groups in a rewritable process. Reversible coding of the nitroxide functional microspheres by NRC and decoding through thermal alkoxyamine fission were monitored and characterized by electron paramagnetic resonance (EPR) spectroscopy and X‐ray photoelectron spectroscopy (XPS). In addition, this nitroxide coating system was exploited in “grafting‐to” polymer surface ligations of poly(methyl methacrylate) (PMMA) and poly(2,2,2‐trifluoroethyl methacrylate) (PTFEMA) in spatially confined areas. Polymer strands terminated with an Irgacure 2959 (2‐hydroxy‐4′‐(2‐hydroxyethoxy)‐2‐methylpropiophenone) photoinitiator were obtained through chain‐transfer polymerization, and subsequently coupled to nitroxide‐immobilized poly(dopamine) (PDA)‐coated silicon substrates by using rapid photoclick NRC reactions. Light‐driven polymer surface coding was visualized by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and XPS imaging.

Radical-Enriched Artificial Melanin

“…However, our nanoparticle synthesis strategy does not involve any organic solvents, heating, or harsh conditions, making it a clean method for preparing these functionalized melanin materials. Note that previous literature reports utilize monomer 2 as a surface coating on planar substrates , and polymeric microspheres . Our work here focuses on the polymerization of monomer 2 in solution for radical-enriched melanin nanoparticles.…”

“…Note that previous literature reports utilize monomer 2 as a surface coating on planar substrates 42,43 and polymeric microspheres. 44 Our work here focuses on the polymerization of monomer 2 in solution for radical-enriched melanin nanoparticles.…”

3D-printed titanium implant-coated polydopamine for repairing femoral condyle defects in rabbits

“…1, 2, 3, 4, the mean diameter of PDA particle was 100-300 nm and the SEM images demonstrated significant numbers of spherical particles formed on the surface of the 3D PPT which increased greatly the surface area. The previous studies showed that PDA preparation on substrates can provide many hydroxyl groups(OH-), attracting calcium ions (Ca2+) and subsequently bond with phosphate ions (PO3-)which could improve the bioactivity of 3D PPT, forming a stronger interlock with the bone tissue [17][18][19][20].…”

A Versatile Light‐Triggered Radical‐Releasing Surface Coating Technology

“…[58] While nitroxides and alkoxyamine have been investigated as the responsive chemistries in these dynamic materials, materials and surfaces that can dynamically control the availability of nitroxides are not widely studied. [59][60][61] In the pursuit of developing dynamic and responsive nitroxide functionalized surfaces, we have designed a light responsive system, that can be attached to a variety of material surfaces. Here, we present the synthesis and characterization of a nitroxide-o-nitrobenzyl-silane reagent (Figure 2), and demonstrated its applicability with silicon, plastic, and silica surfaces.…”