Dendron-Polymer Hybrids as Tailorable Coronae of Single-Walled Carbon Nanotube

Single-walled carbon nanotubes (SWCNTs), non-covalently functionalized by synthetic polymers, find widespread applications including sensing and imaging. Identifying new amphiphiles with interchangeable building blocks that can form unique coronae around the SWCNT, customized for a specific application, is thus of great interest. We present polymer-dendron hybrids, composed of hydrophobic dendrons and hydrophilic polyethylene glycol (PEG), as amphiphilic macromolecules with high degree of structural freedom, for suspending SWCNTs in aqeous solution. Based on a set of four PEG-dendrons differing in their dendritic end-groups, we show thst differences in the chemical structure of the hydrophobic end-groups control the interactions of the PEG-dendrons with the SWCNT-surface. These interactions led to differences in the intrinsic near-infrared fluorescence emission of the SWCNTs and affected the PEG-dendron susceptibility to enzymatic degradation, which was monitored by the SWCNT fluorescent signal. Our findings open new avenues for rational design of SWCNT functionalization, and optical sensing of enzymatic activity<br>

Dendron-Polymer Hybrids as Tailorable Coronae of Single-Walled Carbon Nanotube

Single-walled carbon nanotubes (SWCNTs), non-covalently functionalized by synthetic polymers, find widespread applications including sensing and imaging. Identifying new amphiphiles with interchangeable building blocks that can form unique coronae around the SWCNT, customized for a specific application, is thus of great interest. We present polymer-dendron hybrids, composed of hydrophobic dendrons and hydrophilic polyethylene glycol (PEG), as amphiphilic macromolecules with high degree of structural freedom, for suspending SWCNTs in aqeous solution. Based on a set of four PEG-dendrons differing in their dendritic end-groups, we show thst differences in the chemical structure of the hydrophobic end-groups control the interactions of the PEG-dendrons with the SWCNT-surface. These interactions led to differences in the intrinsic near-infrared fluorescence emission of the SWCNTs and affected the PEG-dendron susceptibility to enzymatic degradation, which was monitored by the SWCNT fluorescent signal. Our findings open new avenues for rational design of SWCNT functionalization, and optical sensing of enzymatic activity<br>

Miktoarm Star Polymers: Branched Architectures in Drug Delivery

Delivering active pharmaceutical agents to disease sites using soft polymeric nanoparticles continues to be a topical area of research. It is becoming increasingly evident that the composition of amphiphilic macromolecules plays a significant role in developing efficient nanoformulations. Branched architectures with asymmetric polymeric arms emanating from a central core junction have provided a pivotal venue to tailor their key parameters. The build-up of miktoarm stars offers vast polymer arm tunability, aiding in the development of macromolecules with adjustable properties, and allows facile inclusion of endogenous stimulus-responsive entities. Miktoarm star-based micelles have been demonstrated to exhibit denser coronae, very low critical micelle concentrations, high drug loading contents, and sustained drug release profiles. With significant advances in chemical methodologies, synthetic articulation of miktoarm polymer architecture, and determination of their structure-property relationships, are now becoming streamlined. This is helping advance their implementation into formulating efficient therapeutic interventions. This review brings into focus the important discoveries in the syntheses of miktoarm stars of varied compositions, their aqueous self-assembly, and contributions their formulations are making in advancing the field of drug delivery.

Accelerated Reaction Rates within Self-Assembled Polymer Nanoreactors with Tunable Hydrophobic Microenvironments

Performing reactions in the presence of self-assembled hierarchical structures of amphiphilic macromolecules can accelerate reactions while using water as the bulk solvent due to the hydrophobic effect. We leveraged non-covalent interactions to self-assemble filled-polymer micelle nanoreactors (NR) incorporating gold nanoparticle catalysts into various amphiphilic polymer nanostructures with comparable hydrodynamic nanoreactor size and gold concentration in the nanoreactor dispersion. We systematically studied the effect of the hydrophobic co-precipitant on self-assembly and catalytic performance. We observed that co-precipitants that interact with gold are beneficial for improving incorporation efficiency of the gold nanoparticles into the nanocomposite nanoreactor during self-assembly but decrease catalytic performance. Hierarchical assemblies with co-precipitants that leverage noncovalent interactions could enhance catalytic performance. For the co-precipitants that do not interact strongly with gold, the catalytic performance was strongly affected by the hydrophobic microenvironment of the co-precipitant. Specifically, the apparent reaction rate per surface area using castor oil (CO) was over 8-fold greater than polystyrene (750 g/mol, PS 750); the turnover frequency was higher than previously reported self-assembled polymer systems. The increase in apparent catalytic performance could be attributed to differences in reactant solubility rather than differences in mass transfer or intrinsic kinetics; higher reactant solubility enhances apparent reaction rates. Full conversion of 4-nitrophenol was achieved within three minutes for at least 10 sequential reactions demonstrating that the nanoreactors could be used for multiple reactions.

Photothermal-Triggered Shape Memory Polymer Prepared by Cross-Linking Porphyrin-Loaded Micellar Particles

In this work, we fabricated porphyrin-loaded shape memory polymer (SMP) film by cross-linking micellar particles prepared by co-assembly of porphyrin compounds and amphiphilic macromolecules formulated by copolymerization of 2-butoxy ethanol (BCS), methyl methacrylate (MMA), butyl acrylate (BA) acrylic acid (AA), and diacetone acrylamide (DAAM). The experimental results revealed that this film was able to respond to the red light in terms of photothermal effect enabled by the porphyrin filler. The photothermal-triggered shape memory behaviors of the film were further examined in detail. It was noteworthy that this material was expected to have potential applications in the biomedical field due to the excellent biocompatibility of the porphyrin filler and the red-light source, which was optimal and safe enough for biomedical treatment.