Host-guest interaction induced supramolecular amphiphilic star architecture and uniform nanovesicle formation for anticancer drug delivery.

A star polymer of poly[(R,S)-3-hydroxybutyrate] (PHB) with adamantyl end-terminals extended from an α-cyclodextrin (α-CD) core is designed. It subsequently self-assembles to form controllable and uniform nanovesicles induced by host-guest interactions between heptakis(2,6-di-O-methyl)-β-CD and the adamantyl ends. The nanovesicles are suitable for loading and intracellular delivery of the anticancer drug doxorubicin.

Biodegradable hyperbranched amphiphilic polyurethane multiblock copolymers consisting of poly(propylene glycol), poly(ethylene glycol), and polycaprolactone as in situ thermogels.

This paper reports the synthesis and characterization of new hyperbranched amphiphilic polyurethane multiblock copolymers consisting of poly(propylene glycol) (PPG), poly(ethylene glycol) (PEG), and polycaprolactone (PCL) segments as in situ thermogels. The hyperbranched poly(PPG/PEG/PCL urethane)s, termed as HBPEC copolymers, were synthesized from PPG-diol, PEG-diol, and PCL-triol by using 1,6-hexamethylene diisocyanate (HMDI) as a coupling agent. The compositions and structures of HBPEC copolymers were determined by GPC and 1H NMR spectroscopy.

Supramolecular anchoring of DNA polyplexes in cyclodextrin-based polypseudorotaxane hydrogels for sustained gene delivery.

A cyclodextrin-based supramolecular hydrogel system with supramolecularly anchored active cationic copolymer/plasmid DNA (pDNA) polyplexes was studied as a sustained gene delivery carrier. A few biodegradable triblock copolymers of methoxy-poly(ethylene glycol)-b-poly(ε-caprolactone)-b-poly[2-(dimethylamino)ethyl methacrylate] (MPEG-PCL-PDMAEMA) with well-defined cationic block lengths were prepared to condense pDNA. The MPEG-PCL-PDMAEMA copolymers exhibit good ability to condense pDNA into 275-405 nm polyplexes with hydrophilic MPEG in the outer corona.

Supramolecular hydrogels formed by pyrene-terminated poly(ethylene glycol) star polymers through inclusion complexation of pyrene dimers with γ-cyclodextrin.

Novel supramolecular hydrogels were formed between pyrene-terminated poly(ethylene glycol) star polymers and γ-cyclodextrin (γ-CD), through the inclusion complexation of dimers of the pyrene terminals with γ-CD, where γ-CD was directly used as a supramolecular cross-linking reagent without any modification.

Amphiphilic star-block copolymers and supramolecular transformation of nanogel-like micelles to nanovesicles.

Amphiphilic star-block copolymers based on poly(3-hydroxybutyrate) with adamantyl end-functionalization were synthesized via anionic ring-opening polymerization and alkyne-azide "Click Chemistry" coupling. In aqueous medium, the copolymers self-assembled into nanogel-like large compound micelles, and transformed into vesicular nanostructures under the direction of host-guest interaction between the adamantyl end and dimethyl-β-cyclodextrin.

Chitosan-graft-(PEI-β-cyclodextrin) copolymers and their supramolecular PEGylation for DNA and siRNA delivery.

Two water-soluble chitosan-graft-(polyethylenimine-β-cyclodextrin) (CPC) cationic copolymers were synthesized via reductive amination between oxidized chitosan (CTS) and low molecular weight polyethylenimine-modified β-cyclodextrin (β-CD-PEI). The two polycations, termed as CPC1 and CPC2, were characterized by proton nuclear magnetic resonance spectroscopy, gel permeation chromatography, and elemental analysis. These polycations exhibited good ability to condense both plasmid DNA (pDNA) and small interfering RNA (siRNA) into compact and spherical nanoparticles.

Designing poly[(R)-3-hydroxybutyrate]-based polyurethane block copolymers for electrospun nanofiber scaffolds with improved mechanical properties and enhanced mineralization capability.

Efforts to mineralize electrospun hydrophobic polyester scaffold often require prior surface modification such as plasma or alkaline treatment, which may affect the mechanical integrity of the resultant scaffold. Here through rational design we developed a series of polyurethane block copolymers containing poly[(R)-3-hydroxybutyrate] (PHB) as hard segment and poly(ethylene glycol) (PEG) as soft segment that could be easily fabricated into mineralizable electrospun scaffold without the need of additional surface treatment. To ensure that the block copolymers do not swell excessively in water, PEG content in the polymers was kept below 50 wt %.

Improving hydrophilicity, mechanical properties and biocompatibility of poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate] through blending with poly[(R)-3-hydroxybutyrate]-alt-poly(ethylene oxide).

Natural source poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate] (PHBV) with a low hydroxyvalerate (HV) content ( approximately 8wt.%) was modified by blending it with poly[(R)-3-hydroxybutyrate]-alt-poly(ethylene oxide) (HE) alternating block copolymer. We hypothesized that the adjoining PHB segments could improve the miscibility of the poly(ethylene oxide) segments of HE with the PHBV matrix and therefore improve the physical properties of the PHBV/HE blends.

Synthesis, characterization, and morphology studies of biodegradable amphiphilic poly[(R)-3-hydroxybutyrate]-alt-poly(ethylene glycol) multiblock copolymers.

Novel biodegradable amphiphilic alternating block copolymers based on poly[(R)-3-hydroxybutyrate] (PHB) as biodegradable and hydrophobic block and poly(ethylene glycol) (PEG) as hydrophilic block (PHB-alt-PEG) were successfully synthesized through coupling reaction. Their chemical structures have been characterized by using gel permeation chromatography, (1)H nuclear magnetic resonance, and Fourier transform infrared spectroscopy. Differential scanning calorimetry (DSC) analysis revealed that both PHB and PEG blocks in PHB-alt-PEG block copolymers can crystallize to form separate crystalline phase except in those with a short PEG block (M(n) 600) only PHB crystalline phase has been observed.