We report a new family of clickable poly(ethylene glycol) (PEG)-grafted polyoxetane brush polymers as a potential modular platform for delivery of drugs and imaging agents. 3-Ethyl-3-hydroxymethyloxetane (EHMO) monomer reacted with propargyl benzenesulfonate in the presence of sodium hydride to yield alkyne-substituted monomer (EAMO). Subsequently, cationic ring-opening polymerization using boron trifluoride diethyl etherate catalyst and 1,4-butanediol initiator produced P(EAMO) homopolymer with a DP of ∼30 (30 alkynes per chain). Methoxypoly(ethylene glycol) azide (mPEG750-azide) prepared from mPEG750 (750 g mol-1) was grafted to P(EAMO) via copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) click chemistry. Water-soluble cytocompatible P(EAMO)-g-PEG brush polymers with controlled degrees of PEGylation were synthesized by varying the feed molar ratio of mPEG750-azide to alkyne (25:100, 50:100, 75:100, and 100:100). 1H NMR, GPC, end-group analysis, FTIR, and DSC were applied for polymer characterization. The utility of P(EAMO)-g-PEG for carrying imaging agents was demonstrated by preparing fluorescently labeled P(EAMO)-g-PEG. 5-(Aminoacetamido)fluorescein (AAF) was used as a model compound. Fluorescein-carrying P(EAMO)-g-PEG was synthesized by click coupling bifunctional spacer 6-azidohexanoic acid (AHA) to P(EAMO)-g-PEG and subsequently coupling of AAF to AHA with EDC/NHS chemistry.
- 1 ,4-Butanediol,
- Bifunctional,
- Boron trifluoride diethyl etherate,
- Cationic ring opening polymerization,
- Click chemistry,
- End-group analysis,
- Feed molar ratio,
- FTIR,
- Imaging agent,
- Model compound,
- Modular platform,
- PEgylation,
- Polymer characterization,
- Propargyl,
- Sodium hydrides, Acetylene,
- Boron,
- Brushes,
- Dyes,
- Ethylene glycol,
- Grafting (chemical),
- Monomers,
- Polyethylene oxides,
- Polymers,
- Sodium compounds, Polyethylene glycols
Available at: http://works.bepress.com/hu-yang/68/