Glucose-Responsive Disassembly of Polymersomes of Sequence-Specific Boroxole-Containing Block Copolymers under Physiologically Relevant Conditions

Redox-responsive micelles self-assembled from dynamic covalent block copolymers for intracellular drug delivery

Redox-responsive micelles self-assembled from dynamic covalent block copolymers with double disulfide linkage in the backbone have been developed successfully. The amphiphilic block copolymers PEG-PLA associated with complementary H-bonding sequences can self-assemble into spherical micelles in aqueous media with sizes from 34 nm to 107 nm with different molar mass of PEG and PLA. Moreover, in vitro drug release analyses indicate that reductive environment can result in triggered drug release profiles. The glutathione (GSH) mediated intracellular drug delivery was investigated against HeLa human cervical carcinoma cell line. Flow cytometry and fluorescence microscopy measurements demonstrated that the micelles exhibited faster drug release in glutathione monoester (GSH-OEt) pretreated HeLa cells than that in the nonpretreated cells. Cytotoxicity assay of DOX-loaded micelles indicated the higher cellular proliferation inhibition against 10 mM of GSH-OEt pretreated HeLa cells than that of the nonpretreated ones. These reduction-responsive, biodegradable and biocompatibility micelles could provide a favorable platform to construct excellent drug delivery systems for cancer therapy.

Glucose-responsive polymer vesicles templated by α-CD/PEG inclusion complex

Polymeric nanoparticles with glucose-responsiveness are of great interest in developing a self-regulated drug delivery system. In this work, glucose-responsive polymer vesicles were fabricated based on the complexation between a glucosamine (GA)-containing block copolymer PEG45-b-P(Asp-co-AspGA) and a phenylboronic acid (PBA)-containing block copolymer PEG114-b-P(Asp-co-AspPBA) with α-CD/PEG45 inclusion complex as the sacrificial template. The obtained polymer vesicles composed of cross-linked P(Asp-co-AspGA)/P(Asp-co-AspPBA) layer as wall and PEG chains as both inner and outer coronas. The vesicular morphology was observed by transmission electron microscopy (TEM), and the glucose-responsiveness was investigated by monitoring the variations of hydrodynamic diameter (Dh) and light scattering intensity (LSI) in the polymer vesicle solution with glucose using dynamic light scattering (DLS). Vancomycin as a model drug was encapsulated in the polymer vesicles and sugar-triggered drug release was carried out. This kind of polymer vesicle may be a promising candidate for glucose-responsive drug delivery.

A study on tunable AIE (AIEE) of boron ketoiminate-based conjugated polymers for live cell imaging

In this study, four boron ketoiminate-based conjugated polymers P1–P4 are designed and synthesized via Suzuki polymerization.

Borinic acid block copolymers: new building blocks for supramolecular assembly and sensory applications

Borinic acid functional groups were incorporated into block copolymers via RAFT polymerization and their supramolecular assembly and sensor applications were investigated.

Doubly responsive polymersomes towards monosaccharides and temperature under physiologically relevant conditions

A new class of doubly-responsive block copolymers could be utilized as new delivery vehicles for cargo molecules such as insulin.

Chitosan oligosaccharide copolymer micelles with double disulphide linkage in the backbone associated by H-bonding duplexes for targeted intracellular drug delivery

Folic acid conjugated block copolymer micelles with H-bonding associated double disulphide linkage in the backbone were developed.

A facile strategy to fabricate glucose-responsive vesicles via a template of thermo-sensitive micelles

Polymer vesicles fabricated based on the complexation between PBA- and GA containing block copolymers exhibited glucose-responsiveness at physiological pH.

Phenylboronic Acid-Installed Polycarbonates for the pH-Dependent Release of Diol-Containing Molecules

Environmental responsiveness is an appealing trait of emerging polymeric materials, as shown for a variety of pH-responsive drug delivery systems. The chemical versatility of the conjugation site and conjugate lability to physiologically relevant changes in pH will largely determine their applicability. Herein, we report on the use of a drug-polymer complex based on boronic acid-functionalized polycarbonates (PPBC) as the substrate for the pH-sensitive delivery of a diol-containing drug, capecitabine (CAPE). Complexation of CAPE with a PEGylated-PPBC block copolymer, via boronic ester formation, resulted in amphiphiles capable of self-assembling into spherical nanoparticles. We examined nanoparticle stability and release kinetics in neutral and acidic media and relate differences in release profiles and particle stability with changes to polymer chemistry. Comparison of complexed nanoparticles with their noncomplex analogues revealed striking differences in release rate and particle stability. Illustrated herein for capecitabine, the pH-sensitive dissociation of boronate esters from PPBCs can be applied in a general manner to diol- or catechol-containing solutes, demonstrating the utility of these polymers for biomedical applications.

Glucose-responsive hydrogels based on dynamic covalent chemistry and inclusion complexation

A novel glucose-responsive hydrogel system based on dynamic covalent chemistry and inclusion complexation was described. Hydrogels are formed by simply mixing the solutions of three components: poly(ethylene oxide)-b-poly vinyl alcohol (PEO-b-PVA) diblock polymer, α-cyclodextrin (α-CD) and phenylboronic acid (PBA)-terminated PEO crosslinker. Dynamic covalent bonds between PVA and PBA provide sugar-responsive crosslinking, and the inclusion complexation between PEO and α-CD can promote hydrogel formation and enhance hydrogel stability. The ratios of the three components have a remarkable effect on the gelation time and the mechanical properties of the final gels. In rheological measurements, the hydrogels are demonstrated to possess solid-like behaviour and good structural recovery ability after yielding. The sugar-responsiveness of the hydrogels was examined by protein loading and release experiments, and the results indicate that this property is also dependent on the compositions of the gels; at a proper component ratio, a new glucose-responsive hydrogel system operating at physiological pH can be obtained. The combination of good biocompatibility of the three components and the easy preparation of hydrogels with tunable glucose-responsiveness may enable an alternative design of hydrogel systems that finds potential applications in biomedical and pharmaceutical fields, such as treatment of diabetes.

Synthesis and volume phase transition of concanavalin A-based glucose-responsive nanogels

A glucose-responsive nanogel that can undergo reversible and rapid volume phase transitions is made of ConA interpenetrated in a poly(NIPAM) network.

Stimuli-responsive nanocarriers for drug delivery

Spurred by recent progress in materials chemistry and drug delivery, stimuli-responsive devices that deliver a drug in spatial-, temporal- and dosage-controlled fashions have become possible. Implementation of such devices requires the use of biocompatible materials that are susceptible to a specific physical incitement or that, in response to a specific stimulus, undergo a protonation, a hydrolytic cleavage or a (supra)molecular conformational change. In this Review, we discuss recent advances in the design of nanoscale stimuli-responsive systems that are able to control drug biodistribution in response to specific stimuli, either exogenous (variations in temperature, magnetic field, ultrasound intensity, light or electric pulses) or endogenous (changes in pH, enzyme concentration or redox gradients).

Responsive materials for self-regulated insulin delivery

With diabetes mellitus becoming an important public health concern, insulin-delivery systems are attracting increasing interest from both scientific and technological researchers. This feature article covers the present state-of-the-art glucose-responsive insulin-delivery system (denoted as GRIDS), based on responsive polymer materials, a promising system for self-regulated insulin delivery. Three types of GRIDS are discussed, based on different fundamental mechanisms of glucose-recognition, with: a) glucose enzyme, b) glucose binding protein, and c) synthetic boronic acid as the glucose-sensitive component. At the end, a personal perspective on the major issues yet to be worked out in future research is provided.