Transformation of RAFT Polymer End Groups into Nitric Oxide Donor Moieties: En Route to Biochemically Active Nanostructures

Abstract

Synthesis and Characterization Methods A. MaterialsOligo(ethylene glycol) methyl ether methacrylate (OEGMA) with M n = 300 g mol -1 or 500 g mol -1 (denoted as OEGMA 300 or OEGMA 500 where relevant) were purchased from Sigma-Aldrich and deinhibited by percolating over a column of basic alumina. 2-(dimethylamino)ethyl methacrylate (DMAEMA) and 2-(diisopropylamino)ethyl methacrylate (DIPMA) were purchased from Sigma-Aldrich and passed through a column of basic alumina in order to remove inhibitor. Azobisisobutyronitrile (AIBN) was purified by recrystallization from methanol before use. 4-Cyano-4-(phenylcarbonothioylthio)pentanoic acid (CPADB), hydrazine monohydrate, poly(ethylene glycol) methyl ether thiol (PEG-SH) (M n = 2000 g mol -1 ), and 5,5'-dithio-bis(2-nitrobenzoic acid) were purchased from Sigma-Aldrich at the highest purity available and were used as received. Sodium nitrite (NaNO 2 ) and sulphuric acid (98%) were purchased from Ajax Finechem and RCI Labscan, respectively, and used as received. Petroleum ether (b.p. 40 -60 °C), diethyl ether, toluene, dimethylformamide and dioxane were purchased from Merck Millipore and used as received. 5,6-diaminofluorescein (D0084, Chemodex Customized Molecules) was obtained from Sapphire Biosciences (Sydney, Australia).

Enhancing Microcirculation on Multitriggering Manner Facilitates Angiogenesis and Collagen Deposition on Wound Healing by Photoreleased NO from Hemin-Derivatized Colloids

“…Figure 2c shows the good stability of NO on PB-hemin that less than 20% of NO release was seen after 7 days at different storage conditions. These experiments present an appreciable stability compared with the reported NO delivery systems, which showed rapid NO-release behavior at room temperature 28,29 and also indicate that PB-NO can be triggered by NIR light to conduct a controllable NO-release fashion. Further to consider the structural stability, TEM measurements and the macroscopic observation of the colloidal solutions displayed no morphology and size change and no precipitation, which has given a blue appearance in the course of storage under different mediums (Figure S6).…”

Nitric Oxide (NO)-Releasing Macromolecules: Rational Design and Biomedical Applications

“…As such, it would be straightforward to synthesize SNO-terminated polymers via the combination of RAFT polymerization, RAFT agent removal, and nitrosation modification. For example, the benzodithioate terminal of a diblock copolymer synthesized by RAFT polymerization was successively transformed into a free thiol and SNO motif in the presence of hydrazine and nitrite, respectively (Yu et al, 2015). The NO release kinetics can be modulated by the solution pH and the formation of micellar nanoparticles at basic condition can markedly slow down the NO release rate (Hu et al, 2014a).…”

RAFT-Based Polymers for Click Reactions

“…The conversion of thiocarbonylthio moiety in the ZC(=S)S group occurs through reactions with appropriate nucleophiles [ 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 ] ( Table 2 ) that include mainly primary amines [ 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 ] and hydrazine (or hydrazine hydrate) [ 116 , 117 , 118 , 119 , 120 , 121 ], alkali [ 122 ], and NaN 3 [ 115 ], along with reducing agents such as NaBH 4 [ 123 , 124 , 125 , 126 , 127 ] and LiB(C 2 H 5 ) 3 H [ 128 ]. The choice of the nucleophile depends on the chemical nature of the stabil...…”