Catalytically Active Single-Chain Polymeric Nanoparticles: Exploring Their Functions in Complex Biological Media.

Dynamic single-chain polymeric nanoparticles (SCPNs) are intriguing, bioinspired architectures that result from the collapse or folding of an individual polymer chain into a nanometer-sized particle. Here we present a detailed biophysical study on the behavior of dynamic SCPNs in living cells and an evaluation of their catalytic functionality in such a complex medium. We first developed a number of delivery strategies that allowed the selective localization of SCPNs in different cellular compartments.

Surface water retardation around single-chain polymeric nanoparticles: critical for catalytic function?

A library of water-soluble dynamic single-chain polymeric nanoparticles (SCPN) was prepared using a controlled radical polymerisation technique followed by the introduction of functional groups, including probes at targeted positions. The combined tools of electron paramagnetic resonance (EPR) and Overhauser dynamic nuclear polarization (ODNP) reveal that these SCPNs have structural and surface hydration properties resembling that of enzymes.

Cleaning the Click: A Simple Electrochemical Avenue for Copper Removal from Strongly Coordinating Macromolecules.

We introduce a novel electrochemical method for the purification of complex water-soluble functional polymers contaminated with copper salts originating from copper-catalyzed azide/alkyne ligation chemistry, for which no standard purification protocol is suitable. A triethylene glycol methyl ether methacrylate (TEGMA) star polymer with 2-ureido-4-pyrimidone (UPy) end groups was prepared via an activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) and copper-catalyzed azide/alkyne cycloaddition (CuAAc) and selected as a model system for electrolysis of an aqueous polymer solution. We systematically investigate the influence of sample concentration, voltage, and time of electrolysis on the quality of the purification.

A modular approach to introduce function into single-chain polymeric nanoparticles.

Here, a modular approach is reported to introduce a specific function into single-chain polymeric nanoparticles (SCPNs). Hereto, an amphiphilic polymer with pendant benzene-1,3,5-tricarboxamide (BTA) units is mixed with a "free" BTA that contains a functional group, either a fluorescent naphthalimide or a catalytically active l-proline. Taking advantage of hydrophobic interactions and self-recognition properties of the BTA units, the "free" BTAs are captured into the interior of the SCPN in water as evidenced by fluorescence studies.

Consequences of block sequence on the orthogonal folding of triblock copolymers.

ABA- and BAB-type triblock copolymers possessing pendant, self-assembling motifs in the A and B blocks were synthesized, with 2-ureidopyrimidinone (UPy) and benzene-1,3,5-tricarboxamide (BTA) for the A and B block, respectively. They were investigated to assess if and how the polymer's microstructure influences the self-assembly behavior of the supramolecular motifs and, as a result, the single-chain folding process. BAB-type triblock copolymers were synthesized via atom transfer radical polymerization (ATRP) with molecular weights ranging from 30 to 120 kg mol⁻¹; the BTA and UPy motifs were attached using a post-functionalization approach.

Unusual analyte-matrix adduct ions and mechanism of their formation in MALDI TOF MS of benzene-1,3,5-tricarboxamide and urea compounds.

Analyte-matrix adducts are normally absent under typical matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) conditions. Interestingly, though, in the analysis of several types of organic compounds synthesized in our laboratory, analyte-matrix adduct ion peaks were always recorded when common MALDI matrices such as 4-hydroxy-α-cyanocinnamic acid (CHCA) were used. These compounds are mainly those with a benzene-1,3,5-tricarboxamide (BTA) or urea moiety, which are important building blocks to make new functional supramolecular materials.

Evaporative self-assembly of single-chain, polymeric nanoparticles.

Evaporative self-assembly of dilute solutions containing single-chain polymeric nanoparticles results in characteristic morphologies imaged using atomic force microscopy. Quantitative comparison of experimental data to morphologies obtained by lattice-gas simulations shows that the nonequilibrium patterns emerge from a complex interplay between dewetting, solvent evaporation and nanoparticle diffusion.

How far can we push polymer architectures?

We here report the synthesis and characterization of a complex polymeric architecture based on a block copolymer with a cylindrical brush block and a single-chain polymeric nanoparticle block folded due to strong intramolecular hydrogen-bonds. The self-assembly of these constructs on mica surfaces was studied with atomic force microscopy, corroborating the distinct presence of block copolymer architectures.

Symmetry breaking in the self-assembly of partially fluorinated benzene-1,3,5-tricarboxamides.

The interplay of two subsequent aggregation processes results in a symmetry-breaking phenomenon in an achiral self-assembling system. Partially fluorinated benzene-1,3,5-tricarboxamide molecules self-assemble into a racemic mixture of one-dimensional P- and M-helical aggregates, followed by bundling into optically active higher-order aggregates or fibers.

Hydrogen bonding directed supramolecular polymerisation of oligo(phenylene-ethynylene)s: cooperative mechanism, core symmetry effect and chiral amplification.

The design of supramolecular motifs with tuneable stability and adjustable supramolecular polymerisation mechanisms is of crucial importance to precisely control the properties of supramolecular assemblies. This report focuses on constructing π-conjugated oligo(phenylene ethynylene) (OPE)-based one-dimensional helical supramolecular polymers that show a cooperative growth mechanism. Thus, a novel set of discotic molecules comprising a rigid OPE core, three amide groups, and peripheral solubilising wedge groups featuring C(3) and C(2) core symmetry was designed and synthesised.

Dynamic supramolecular polymers based on benzene-1,3,5-tricarboxamides: the influence of amide connectivity on aggregate stability and amplification of chirality.

N-Centred benzene-1,3,5-tricarboxamides (N-BTAs) composed of chiral and achiral alkyl substituents were synthesised and their solid-state behaviour and self-assembly in dilute alkane solutions were investigated. A combination of differential scanning calorimetry (DSC), polarisation optical microscopy (POM) and X-ray diffraction revealed that the chiral N-BTA derivatives with branched 3,7-dimethyloctanoyl chains were liquid crystalline and the mesophase was assigned as Col(ho). In contrast, N-BTA derivatives with linear tetradecanoyl or octanoyl chains lacked a mesophase and were obtained as crystalline compounds.

Probing the limits of the majority-rules principle in a dynamic supramolecular polymer.

By systematic variation of the chemical structure of benzene-1,3,5-tricarboxamide (BTA) derivatives, the effect of chemical structure on the amplification of chirality was studied and quantified. In combination with temperature-dependent amplification experiments, the limits of the majority-rules principle were also investigated. For all BTA derivatives a high, constant helix reversal penalty was determined, which is related to the intermolecular hydrogen bonds that are present in all studied derivatives.

Asymmetrically substituted benzene-1,3,5-tricarboxamides: self-assembly and odd-even effects in the solid state and in dilute solution.

Molecular organization: Chiral benzene tricarboxamides with methyl substituents at defined positions self-assemble into supramolecular polymers of preferred helicity by three-fold alpha-helical-type hydrogen bonding. The odd-even effect is operative and all derivatives are liquid crystalline showing a Col(ho) phase (see figure).Asymmetric benzene-1,3,5-tricarboxamides (aBTAs) comprising two n-octyl and one chiral methyl-alkyl side chain were synthesised and characterised.

Multimodality scar management program.

Background: This trial was undertaken to assess the efficacy of a multimodality management regime used for the prevention of hypertrophic scars. It follows previous research and experience (A.D.

The influence of ethylene glycol chains on the thermodynamics of hydrogen-bonded supramolecular assemblies in apolar solvents.

Substitution of hydrogen bond directed supramolecular assemblies with ethylene glycol chains leads to a reduction in the association constant in apolar solvents, where the reduction of the association constant is dependent on the length of the aliphatic spacer connecting the hydrogen bonds and the ethylene glycol chain.

New innovations in scar management.

As current aesthetic surgical techniques become more standardized and results more predictable, a fine scar may be the demarcating line between acceptable and unacceptable aesthetic results. With this in mind, a scar management program has been adopted based on the modalities of wound support, hydration, and hastened maturity, all factors gleaned from scientific evidence published over the past 25 years. Tension on a scar in one axis will result in a stretched scar, probably initiated by neutrophils and their neutral proteases [18,26].