A Multiresponsive Amphiphilic Supramolecular Diblock Copolymer Based on Pillar[10]arene/Paraquat Complexation for Rate‐Tunable Controlled Release

120

With the advancement of polymer engineering, complex star-shaped polymer architectures can be synthesized with ease, bringing about a host of unique properties and applications. The polymer arms can be functionalized with different chemical groups to fine-tune the response behavior or be endowed with targeting ligands or stimuli responsive moieties to control its physicochemical behavior and self-organization in solution. Rheological properties of these solutions can be modulated, which also facilitates the control of the diffusion of the drug from these star-based nanocarriers. However, these star-shaped polymers designed for drug delivery are still in a very early stage of development. Due to the sheer diversity of macromolecules that can take on the star architectures and the various combinations of functional groups that can be cross-linked together, there remain many structure-property relationships which have yet to be fully established. This review aims to provide an introductory perspective on the basic synthetic methods of star-shaped polymers, the properties which can be controlled by the unique architecture, and also recent advances in drug delivery applications related to these star candidates.

Section: Introductionmentioning

confidence: 99%

Nano‐Star‐Shaped Polymers for Drug Delivery Applications

Yang

Deen

et al. 2017

120

“…One example is presented by Zhu's group who prepared an O 2 ‐“breathing” vesicle upon alternately purging with O 2 and Ar. Noteworthy, SRPVs with dual or multiresponsiveness have attracted enormous attention because multiresponsive systems can greatly improve their versatility in a variety of applications . In contrast to lots of contact‐triggered stimuli responses, light is a contact‐free and environment‐friendly stimulus .…”

Section: Introductionmentioning

confidence: 99%

“…Noteworthy, SRPVs with dual or multiresponsiveness have attracted enormous attention because multiresponsive systems can greatly improve their versatility in a variety of applications. [31][32][33][34] In contrast to lots of contact-triggered stimuli responses, light is a contact-free and environment-friendly stimulus. [35] Therefore, light is one of the most common triggers to realize remote controlled release.…”

mentioning

confidence: 99%

“Breathing” CO₂‐, O₂‐, and Light‐Responsive Vesicles from a Triblock Copolymer for Rate‐Tunable Controlled Release

Song

Shang

Zhang

et al. 2017

group [26] who prepared an O 2 -"breathing" vesicle upon alternately purging with O 2 and Ar. Noteworthy, SRPVs with dual or multiresponsiveness have attracted enormous attention because multiresponsive systems can greatly improve their versatility in a variety of applications. [31][32][33][34] In contrast to lots of contact-triggered stimuli responses, light is a contact-free and environment-friendly stimulus. [35] Therefore, light is one of the most common triggers to realize remote controlled release. [36,37] So far, to the best of our knowledge, combining light responsiveness with CO 2 and O 2 -responsiveness to prepare triple-responsive vesicles has not yet been explored. A further challenge of such a vesicular system, besides the synthetic challenge, is how to maintain its "breathing"-responsive behavior instead of causing a sharp disassembly or a vesicle-tomicelle transition upon external stimuli (CO 2 , O 2 , and light). Usually, apart from cross-linked vesicles, a suitable polymer structure is an efficient strategy to endow SRPVs with a swelling responsive behavior to achieve a tunable membrane permeability. [15,38] In the present work, we report on the first CO 2 -, O 2 -, and lightresponsive vesicles from an amphiphilic triblock copolymer. To fabricate "breathable" vesicles, the work from Feng's group was referred to for the design of suitable chemical structures of triblock copolymers. [38] In this case, poly(N,N-dimethylamino ethyl methacrylate-co-2,2,2-trifluoroethyl methacrylate) (P(DMAEMAco-TFEMA)) with CO 2 and O 2 -responsiveness was chosen as the middle block, and poly(4-(4-methoxy-phenylazo)phenoxy methacrylate) (PMEPPMA) with light responsiveness was chosen as the end block. Due to the rigid structure of PMEPPMA, selfassembled vesicles can exhibit only swollen transitions upon CO 2 and O 2 stimulation, rather than switching to micelles or dissociating into unimers. Based on this suitable chemical structure and stimuli responsiveness, such vesicles present a "breathing" behavior under external stimulation (see Scheme 1), indicating the membrane permeability of such vesicles can be controlled via a single stimulus or various stimuli combinations. Furthermore, using Calcein as a model, it is demonstrated that the vesicles with their altering membrane permeability could serve as potential nanocarriers for an efficient rate-tunable controlled drug release. Results and DiscussionHerein, a CO 2 -, O 2 -, and light-responsive amphiphilic triblock copolymer, poly[(ethylene glycol)methyl ether]-block-poly(N,Ndimethylamino ethyl methacrylate-co-2,2,2-trifluoroethyl

“…Among them, the supramolecular polymers constructed by polymeric segments have recently drawn much attention due to their unique stimuli responsiveness and sophisticated functions . Nowadays, host–guest interaction is recognized as one of the most important classes of noncovalent interactions and is extensively utilized to build supramolecular polymers . To date, a variety of supramolecular polymers are widely applied to construct supramolecular polymeric nanoparticles such as vesicles and micelles, which exhibit great advantages in cancer therapy .…”

Section: Methodsmentioning

confidence: 99%

Fabrication of a Dual‐Stimuli‐Responsive Supramolecular Micelle from a Pillar[5]arene‐Based Supramolecular Diblock Copolymer for Photodynamic Therapy

Lei

Liu

et al. 2019

A pH and thermo dual‐responsive supramolecular diblock copolymer is constructed by host–guest recognition of pillar[5]arene and viologen salt. The host polymer, poly(N,N‐dimethylaminoethyl methacrylate) bearing pillar[5]arene as the terminal group (P[5]A‐PDMAEMA) is synthesized by atom transfer radical polymerization (ATRP). Guest polymer, ethyl viologen‐ended poly(N‐isopropylacrylamide) (EV‐PNIPAM) is prepared by reversible addition–fragmentation chain transfer polymerization. The supramolecular diblock copolymer can be self‐assembled into stable supramolecular nanoparticles in aqueous solution at 40 °C, which show excellent pH and thermo responsiveness. The nanoparticles are further applied in the encapsulation of photosensitizers (pyropheophorbide‐a, PhA) for photodynamic therapy (PDT). The dual‐responsive nanoparticles can efficiently release PhA in acidic environment at 25 °C. Based on the result of cell experiments, PhA‐loaded nanomicelles exhibit excellent PDT efficacy and low dark toxicity toward A549 cells. Thus, this supramolecular diblock copolymer enriches the methodology of constructing stimuli‐responsive drug carriers and presents a great potential in PDT.