Molecular Approach to Conjugated Polymers with Biomimetic Properties.

The field of bioelectronics involves the fascinating interplay between biology and human-made electronics. Applications such as tissue engineering, biosensing, drug delivery, and wearable electronics require biomimetic materials that can translate the physiological and chemical processes of biological systems, such as organs, tissues. and cells, into electrical signals and vice versa.

Manipulation of cytokine secretion in human dendritic cells using glycopolymers with picomolar affinity for DC-SIGN.

The human C-type lectin DC-SIGN (CD209) is a significant receptor on the surface of dendritic cells (DCs) - crucial components of host defense that bridge the innate and adaptive immune systems. A range of linear glycopolymers, constructed controlled radical polymerization techniques have been shown to interact with DC-SIGN with affinities in the physiologically active range. However, these first generation glycopolymers possess limited structural definition and their effects on DCs were not known.

One-Pot Synthesis of Charged Amphiphilic Diblock and Triblock Copolymers Via High-Throughput Cu(0)-Mediated Polymerization.

Block copolymers containing functionalized monomers, for example those containing charged groups, can be used for many purposes, one of which is the design of polymeric supramolecular materials based on electrostatic interactions. In this paper the synthesis of diblock copolymers and ABA-triblock copolymers containing poly(-butyl acrylate) as a first or middle block and poly(2-(dimethylamino)ethyl acrylate), poly(1-ethoxyethyl acrylate) and poly(1-ethoxyethyl-2-carboxyethyl acrylate) as second or outer blocks, resulting in block copolymers that can contain positive or negative charges, is reported. The polymerizations were performed and optimized via one-pot sequential monomer addition reactions via Cu(0)-mediated polymerization using an automated parallel synthesizer.

One-Pot Automated Synthesis of Quasi Triblock Copolymers for Self-Healing Physically Crosslinked Hydrogels.

The preparation of physically crosslinked hydrogels from quasi ABA-triblock copolymers with a water-soluble middle block and hydrophobic end groups is reported. The hydrophilic monomer N-acryloylmorpholine is copolymerized with hydrophobic isobornyl acrylate via a one-pot sequential monomer addition through reversible addition fragmentation chain-transfer (RAFT) polymerization in an automated parallel synthesizer, allowing systematic variation of polymer chain length and hydrophobic-hydrophilic ratio. Hydrophobic interactions between the outer blocks cause them to phase-separate into larger hydrophobic domains in water, forming physical crosslinks between the polymers.

Supramolecular polymer networks: hydrogels and bulk materials.

Supramolecular polymer networks are materials crosslinked by reversible supramolecular interactions, such as hydrogen bonding or electrostatic interactions. Supramolecular materials show very interesting and useful properties resulting from their dynamic nature, such as self-healing, stimuli-responsiveness and adaptability. Here we will discuss recent progress in polymer-based supramolecular networks for the formation of hydrogels and bulk materials.

Tuning of Polymeric Nanoparticles by Coassembly of Thermoresponsive Polymers and a Double Hydrophilic Thermoresponsive Block Copolymer.

The coassembly behavior of thermoresponsive statistical copolymers and a double hydrophilic block copolymer having a permanently hydrophilic block and a thermoresponsive block is investigated. By adjusting the hydrophilicity of the thermoresponsive statistical copolymers, hybrid nanoparticles are obtained with various ratios of the two species. Importantly, the size of these nanoparticles can be controlled in between 40 and 250 nm dependent on the TCP and the amount of statistical copolymers in the solution.

One-Pot Preparation of Inert Well-Defined Polymers by RAFT Polymerization and In Situ End Group Transformation.

A one-pot procedure that straightforwardly combines reversible addition-fragmentation chain transfer (RAFT) polymerization and end group transformation to remove the RAFT end groups is developed for the synthesis of well-defined poly(meth)acrylates and polyacrylamides with inert end groups. This procedure only requires the addition of an amine at the end of the standard RAFT polymerization procedure, which avoids the separation and purification of the intermediate polymers and, hence, extremely reduces the working time and utilized amount of solvents. Upon addition of the amine, a thiol group is formed by aminolysis of the thiocarbonylthio group, which subsequently undergoes Michael addition with unreacted monomer leading to an inert thioether functionalized polymer.

Degradable ketal-based block copolymer nanoparticles for anticancer drug delivery: a systematic evaluation.

Low solubility of potent (anticancer) drugs is a major driving force for the development of noncytotoxic, stimuli-responsive nanocarriers, including systems based on amphiphilic block copolymers. In this regard, we investigated the potential of block copolymers based on 2-hydroxyethyl acrylate (HEA) and the acid-sensitive ketal-containing monomer (2,2-dimethyl-1,3-dioxolane-4-yl)methyl acrylate (DMDMA) to form responsive drug nanocarriers. Block copolymers were successfully synthesized by sequential reversible addition-fragmentation chain transfer (RAFT) polymerization, in which we combined a hydrophilic poly(HEA)x block with a (responsive) hydrophobic poly(HEAm-co-DMDMAn)y copolymer block.

RAFT polymerization of 4-vinylphenylboronic acid as the basis for micellar sugar sensors.

Well-defined homo and mPEGylated block (co)polymers of the commercially available unprotected 4-vinylphenylboronic acid (4-VBA) monomer are reported based on reversible addition-fragmentation chain transfer (RAFT) polymerization. The polymerization kinetics are studied in detail for homo and block (co)polymerizations with different chain transfer agents (CTAs) to optimize the preparation of well-defined polymer structures, eventually leading to comparatively low dispersities (Đ ≤ 1.25).

Poly(2-oxazoline) hydrogel monoliths via thiol-ene coupling.

Copoly(2-oxazoline)s, prepared by the cationic ring-opening polymerization of 2-(dec-9-enyl)-2-oxazoline with either 2-methyl-2-oxazoline or 2-ethyl-2-oxazoline, are crosslinked with small dithiol molecules under UV irradiation to form homogeneous networks. In situ monitoring of the crosslinking reaction by photo-rheology reveals the formation of soft gels within minutes. The degree of swelling in water is tunable based on the hydrophilicity of the starting macromers and the proportion of alkene side arms present.

Controlled Alternate Layer-by-Layer Assembly of Lectins and Glycopolymers Using QCM-D.

Layer-by-layer (LBL) assembly of concanavalin A (Con A), peanut agglutinin (PNA) plant lectins, and well-defined synthetic glycopolymers via their biological affinities have been prepared using a quartz crystal microbalance with dissipation monitoring (QCM-D). We demonstrate the use of mannose/galactose glycopolymers as lectin binders due to their selective binding to Con A/PNA, respectively. A detailed analysis of the adsorption processes and the adsorbed layer are provided and tuning the composition of multilayers using a series of well-defined glycopolymers differing only in the pendant sugar ratio is discussed.

Salt-induced disintegration of lysozyme-containing polyelectrolyte complex micelles.

The salt-induced disintegration of lysozyme-filled polyelectrolyte complex micelles, consisting of positively charged homopolymers (PDMAEMA150), negatively charged diblock copolymers (PAA42-PAAm417), and lysozyme, has been studied with dynamic light scattering (DLS) and small-angle neutron scattering (SANS). These measurements show that, from 0 to 0.2 M NaCl, both the hydrodynamic radius (Rh) and the core radius (Rcore) decrease with increasing salt concentration.