Multi-Stimuli Responsive Sequence Defined Multi-Arm Star Diblock Copolymers for Controlled Drug Release

Star-shaped polymeric materials provide very high efficiency toward various engineering and biomedical applications. Due to the absence of straightforward and versatile synthetic protocols, the synthesis of sequence-defined star-shaped (co)polymers has remained a major challenge. Here, a facile approach is developed that allows synthesis of a series of unprecedented discrete, multifunctional four-, six-, and eight-arm star-shaped complex macromolecular architectures based on a well-defined triple (thermo/pH/light)-stimuli-responsive poly(N-isopropylacrylamide)-block-poly(methacrylic acid)-umbelliferone (PNIPAM-b-PMAA)n-UMB diblock copolymer, based on temperature responsive PNIPAM segment, pH-responsive PMAA segment, and photoresponsive UMB end groups. Thus, developed star-shaped copolymers self-assemble in water to form spherical nanoaggregates of diameter 90 ± 20 nm, as measured by FESEM. The star-shaped copolymer's response to external stimuli has been assessed against changes in temperature, pH, and light irradiation. The star-shaped copolymer was employed as a nanocarrier for pH responsive release of an anticancer drug, doxorubicin. This study opens up new avenues for efficient star-shaped macromolecular architecture construction for engineering and biomedical applications.

Dendronized Gelatins Showing Both LCST and UCST-type Thermoresponsive Behavior

Modification of natural polymers with stimuli-responsive synthetic moieties witnesses convergences of superior properties from natural polymers and stimuli-responsiveness to generate new intelligent materials. This was usally performed through synthetic polymers...

Amino acid-derived ABCBA-type antifouling biohybrid with multi-stimuli responsivity and contaminant removal capability

A multi-stimuli (pH/thermo/redox)-responsive amphiphilic poly(cysteine methacrylamide)-block-poly(N,N-dimethylaminoethyl methacrylate)-block-polybutadiene-block-poly(N,N-dimethylaminoethyl methacrylate)-block-poly(cysteine methacrylamide) (PCysMAM-b-PDMAEMA-b-PB-b-PDMAEMA-b-PCysMAM) pentablock copolymer biohybrids, based on hydrophobic PB, ampholytic redox responsive PCysMAM and dual (pH and temperature) stimuli responsive PDMAEMA segments,...

l-Histidine-Derived Smart Antifouling Biohybrid with Multistimuli Responsivity

A novel dual pH/thermoresponsive amphiphilic poly(histidine methacrylamide)-block-hydroxyl-terminated polybutadiene-block-poly(histidine methacrylamide) (PHisMAM-b-PB-b-PHisMAM) triblock copolymer biohybrid, composed of hydrophobic PB and ampholytic PHisMAM segments, is developed via direct switching from living anionic polymerization to recyclable nanoparticle catalyst-mediated reversible-deactivation radical polymerization (RDRP). The transformation involved in situ postpolymerization modification of living polybutadiene-based carbanionic species, end-capped with ethylene oxide, into dihydroxyl-terminated polybutadiene and a subsequent reaction with 2-bromo-2-methylpropionyl bromide resulting in a telechelic ATRP macroinitiator (Br-PB-Br). Br-PB-Br was used to mediate RDRP of an l-histidine-derived monomer, HisMAM, yielding a series of PHisMAM-b-PB-b-PHisMAM triblock copolymers. The copolymer's stimuli response was assessed against pH and temperature changes. The copolymer is capable of switching among its zwitterionic, anionic, and cationic forms and exhibited unique antifouling properties in its zwitterionic form. These novel triblock copolymers are expected to be show promising potential in biomedical applications.