Abstract
BackgroundStimuli-responsive polymer materials are a new kind of intelligent materials based on the concept of bionics, which exhibits more significant changes in physicochemical properties upon triggered by tiny environment stimuli, hence providing a good carrier platform for antitumor drug delivery.ResultsDual stimuli-responsive Fe3O4 graft poly(acrylic acid)-block-poly(2-methacryloyloxyethyl ferrocenecarboxylate) block copolymers (Fe3O4-g-PAA-b-PMAEFC) were engineered and synthesized through a two-step sequential reversible addition-fragmentation chain transfer polymerization route. The characterization was performed by FTIR, 1H NMR, SEC, XRD and TGA techniques. The self-assembly behavior in aqueous solution upon triggered by pH, magnetic and redox stimuli was investigated via zeta potentials, vibration sample magnetometer, cyclic voltammetry, fluorescent spectrometry, dynamic light scattering, XPS, TEM and SEM measurements. The experimental results indicated that the Fe3O4-g-PAA-b-PMAEFC copolymer materials could spontaneously assemble into hybrid magnetic copolymer micromicelles with core–shell structure, and exhibited superparamagnetism, redox and pH stimuli-responsive features. The hybrid copolymer micromicelles were stable and nontoxic, and could entrap hydrophobic anticancer drug, which was in turn swiftly and effectively delivered from the drug-loaded micromicelles at special microenvironments such as acidic pH and high reactive oxygen species.ConclusionThis class of stimuli-responsive copolymer materials is expected to find wide applications in medical science and biology, etc., especially in drug delivery system.
Highlights
Stimuli-responsive polymer materials are a new kind of intelligent materials based on the concept of bionics, which exhibits more significant changes in physicochemical properties upon triggered by tiny environment stimuli, providing a good carrier platform for antitumor drug delivery
Synthesis and characterization of the hybrid block copolymers The synthesis of Fe3O4-g-poly(acrylic acid) (PAA)-b-PMAEFC hybrid block copolymers was conducted through a five-step strategy, as presented in Scheme 1
The amino content on the surface of the modified Fe3O4 ferroferric oxide or iron oxide nanoparticles (NPs) was determined by potentiometric titration to be 18.25 mmol g−1; details were described in Additional file 1
Summary
Stimuli-responsive polymer materials are a new kind of intelligent materials based on the concept of bionics, which exhibits more significant changes in physicochemical properties upon triggered by tiny environment stimuli, providing a good carrier platform for antitumor drug delivery. Stimuli-responsive block copolymer drug carriers are a class of functional nanoscaled drug delivery systems (DDS) [1,2,3]. The stimuli-responsive DDS can reduce or avoid the non-controlled release of drugs and enhance the release efficiency of drugs in targeted areas. The stimuli-responsive drug carrier materials sensitive to external environment conditions have become the hot spot of the study of targeted agents [1, 3, 4]. The single stimulus-responsive drug carriers cannot well respond to the complex functions and environments of living systems and suffered the problem of low release accuracy and some side effects [6, 7], which in turn cannot achieve optimal therapy efficiency and meet the demands for efficient overall therapy. Engineering and developing new drug carrier materials with dual or/and multiple stimuli responsiveness is considered to be a very important future direction
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