Switchable Supramolecular Crosslinking of Cyclodextrin-Modified Hyperbranched Polyethylenimine via Anthraquinone Dyes

Supramolecular hyperbranched polymers

This feature article presents a systematic summary of the synthesis strategies including direct and indirect approaches for obtaining supramolecular hyperbranched polymers (SHPs).

Loading and release of fluorescent oligoarginine peptides into/from pH-responsive anionic supramolecular nanoparticles

Supramolecular nanoparticles (SNPs) based on negatively charged polymeric components can act as pH-responsive systems which allow the encapsulation and release of a positively charged cargo by electrostatic interactions. Fluorescent SNPs, based on the negatively charged poly(isobutyl-alt-maleic acid) and labeled with rhodamine B, were used as carriers to encapsulate positively charged Arg_n peptides grafted with a cyanine dye. The energy transfer (FRET) between the dyes residing in a single particle was used to provide a sensing mechanism to study the encapsulation and release of the peptide cargo into/from the SNPs. The change in the spectral signature of the cyanine dye from encapsulated in the SNPs to free in solution was used to characterize the Arg_n release. Finally, in vitro experiments revealed that the Arg_n release from these SNPs occurred at the pH drop that mimics lysosome conditions.

Hyperbranched polymers: advances from synthesis to applications

This review summarizes the advances in hyperbranched polymers from the viewpoint of structure, click synthesis and functionalization towards their applications in the last decade.

Cyclodextrin-based supramolecular systems for drug delivery: recent progress and future perspective

The excellent biocompatibility and unique inclusion capability as well as powerful functionalization capacity of cyclodextrins and their derivatives make them especially attractive for engineering novel functional materials for biomedical applications. There has been increasing interest recently to fabricate supramolecular systems for drug and gene delivery based on cyclodextrin materials. This review focuses on state of the art and recent advances in the construction of cyclodextrin-based assemblies and their applications for controlled drug delivery. First, we introduce cyclodextrin materials utilized for self-assembly. The fabrication technologies of supramolecular systems including nanoplatforms and hydrogels as well as their applications in nanomedicine and pharmaceutical sciences are then highlighted. At the end, the future directions of this field are discussed.

Cyclodextrin-induced host-guest effects of classically prepared poly(NIPAM) bearing azo-dye end groups

A thermo-, pH- and cyclodextrin- (CD) responsive poly(N-isopropylacrylamide) (PNIPAM), with a N,N-dimethylaminoazobenzene end group was synthesized. Using 3-mercaptopropionic acid as a chain transfer agent, PNIPAM with a well-defined COOH end group was obtained. The acid end group was transferred to the corresponding acid chloride and then functionalized with N,N-dimethyl[4-(4'-aminophenylazo)phenyl]amine. This dye-end-group-labeled polymer showed acidochromic effects, depending on the pH and the presence of randomly methylated β-cyclodextrin (RAMEB-CD). Also higher cloud-point values for the lower critical solution temperature (LCST) in the presence of RAMEB-CD were observed. Additionally, this azo-dye-end-group-labeled polymer was complexed with hyperbranched polyglycerol (HPG) decorated with β-CD to generate hedgehog-like superstructures.

Hyperbranched polyethylenimine bearing cyclodextrin moieties showing temperature and pH controlled dye release

The release of anthraquinone dyes from β-cyclodextrin modified, hyperbranched polyethylenimine (PEI-CD) was investigated. 5,8-Dichloro-1,4-dihydroxyanthraquinone (AQ-OH) was enclosed simply by ionic attraction between the phenolate groups of AQ-OH and the protonated amino groups of polyethylenimine (PEI). Additionally, the adamantyl moieties of 1,4-bis-N-adamantylaminoanthraquinone (AQ-Ada) were encapsulated by the cavity of CD modified PEI. Due to these different types of interaction, the dyes can be controllably released from the CD-cavity (AQ-Ada) by temperature variation or from salt encapsulation by pH variation (AQ-OH), as monitored by UV-vis spectroscopy.