3D printed nanocomposites using polymer grafted graphene oxide prepared by multicomponent Passerini reaction

The surface of commercial graphene oxide was modified with polymers using Passerini reaction, which enhances the compatibility between nanoparticles and 3D printing resin.

Biomolecules Turn Self-Assembling Amphiphilic Block Co-polymer Platforms Into Biomimetic Interfaces

Biological membranes constitute an interface between cells and their surroundings and form distinct compartments within the cell. They also host a variety of biomolecules that carry out vital functions including selective transport, signal transduction and cell-cell communication. Due to the vast complexity and versatility of the different membranes, there is a critical need for simplified and specific model membrane platforms to explore the behaviors of individual biomolecules while preserving their intrinsic function. Information obtained from model membrane platforms should make invaluable contributions to current and emerging technologies in biotechnology, nanotechnology and medicine. Amphiphilic block co-polymers are ideal building blocks to create model membrane platforms with enhanced stability and robustness. They form various supramolecular assemblies, ranging from three-dimensional structures (e.g., micelles, nanoparticles, or vesicles) in aqueous solution to planar polymer membranes on solid supports (e.g., polymer cushioned/tethered membranes,) and membrane-like polymer brushes. Furthermore, polymer micelles and polymersomes can also be immobilized on solid supports to take advantage of a wide range of surface sensitive analytical tools. In this review article, we focus on self-assembled amphiphilic block copolymer platforms that are hosting biomolecules. We present different strategies for harnessing polymer platforms with biomolecules either by integrating proteins or peptides into assemblies or by attaching proteins or DNA to their surface. We will discuss how to obtain synthetic structures on solid supports and their characterization using different surface sensitive analytical tools. Finally, we highlight present and future perspectives of polymer micelles and polymersomes for biomedical applications and those of solid-supported polymer membranes for biosensing.

Recent development of brush polymers via polymerization of poly(ethylene glycol)-based macromonomers

Polymerization of poly(ethylene glycol)-based macromonomers is a facile and versatile synthetic method to generate well-defined brush polymers.

Strategies to improve micelle stability for drug delivery

Micelles have been studied as drug delivery carriers for decades. Their use can potentially result in high drug accumulation at the target site through the enhanced permeability and retention effect. Nevertheless, the lack of stability of micelles in the physiological environment limits their efficacy as a drug carrier. In particular, micelles tend to disassociate and prematurely release the encapsulated drugs, lowering delivery efficacy and creating toxicity concerns. Many efforts to enhance the stability of micelles have focused mainly on decreasing the critical micelle forming concentration and improving blood circulation. Herein, we review different strategies including crosslinking and non-crosslinking approaches designed to stabilize micelles and offer perspectives on future research directions.

Covalent Tethering of Temperature Responsive pNIPAm onto TEMPO-Oxidized Cellulose Nanofibrils via Three-Component Passerini Reaction

A critical challenge in the application of functional cellulose fibrils is to perform efficient surface modification without disrupting the original properties. Three-component Passerini reaction (Passerini 3-CR) is regarded as an effective functionalization approach which can be carried out under mild and fast reaction condition. In this study, we investigated the application of Passerini 3-CR for the synthesis of thermoresponsive cellulose fibrils by covalently tethering poly(N-isopropylacrylamide) in aqueous condition at ambient temperature. The three components, a TEMPO-oxidized cellulose nanofiber bearing carboxylic acid moieties (TOCN-COOH), a functionalized polymer with aldehyde group (pNIPAm-COH) and a cyclohexyl isocyanide, were reacted in one pot resulting in 36% of grafting efficiency within 30 min. The chemical coupling was evidenced by improved aqueous dispersibility, which was further confirmed by FT-IR, TGA, UV-vis, and turbidity study. It was observed that the grafting efficiency is strongly dependent on the chain length of the polymer. Furthermore, AFM and X-ray diffraction measurements affirmed the suitability of the proposed method for chemical modification of cellulose nanofibers without significantly compromising the original morphology and structural integrity.

Synthesis of well-defined core–shell nanoparticles based on bifunctional poly(2-oxazoline) macromonomer surfactants and a microemulsion polymerization process

Surface-functional nanoparticles have been fabricated by utilizing bifunctional poly(2-oxazoline) macromonomers as surfactants in a microemulsion process.

Self-assembled micelles prepared from amphiphilic copolymers bearing cell outer membrane phosphorylcholine zwitterions for a potential anti-phagocytic clearance carrier

A versatile strategy using amphiphilic copolymers to prepare micelles with cell membrane mimetic phosphorylcholine shell and PCL core showing potential anti-phagocytic clearance properties was reported.

Enhanced transcellular penetration and drug delivery by crosslinked polymeric micelles into pancreatic multicellular tumor spheroids

The penetration of HPMA-based micelles into multicellular tumor spheroids depends on transcellular transport from peripheral to inner cells. Stabilisation by crosslinking facilitated the penetration.

Disulfide cross-linked phosphorylcholine micelles for triggered release of camptothecin

A series of block copolymers based on 2-methacryloyloxyethyl phosphorylcholine (MPC) were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Incorporation of dihydrolipoic acid (DHLA) into the hydrophobic block led to formation of block copolymer micelles in water. The micelles were between 15 and 30 nm in diameter, as characterized by dynamic light scattering (DLS), with some size control achieved by adjusting the hydrophobic/hydrophilic balance. Cross-linked micelles were prepared by disulfide formation, and observed to be stable in solution for weeks. The micelles proved amenable to disassembly when treated with a reducing agent, such as dithiothreitol (DTT), and represent a potential delivery platform for chemotherapeutic agents. As a proof-of-concept, camptothecin (CPT) was conjugated to the polymer scaffold through a disulfide linkage, and release of the drug from the micelle was monitored by fluorescence spectroscopy. These CPT-loaded prodrug micelles showed a reduction in release rate compared to physically encapsulated CPT. The use of disulfide conjugation facilitated drug release under reducing conditions, with a half-life (t1/2) of 5.5 h in the presence of 3 mM DTT, compared to 28 h in PBS. The toxicity of the micellar prodrugs was evaluated in cell culture against human breast (MCF7) and colorectal (COLO205) cancer cell lines.

'Pseudo-star' Copolymers Formed by a Combination of RAFT Polymerization and Isocyanate-Coupling

We describe the formation of pseudo-star copolymers via incorporation of an isocyanate-bearing monomer, dimethyl meta-isopropenyl benzyl isocyanate (TMI) into a homopolymer of butyl acrylate (BA) using a one-pot, two-step synthesis. The resultant product maintains the functionality of the isocyanate moiety, which is used to attach poly(ethylene glycol) methyl ether onto the copolymeric chain under benign reaction conditions. The resultant pseudo-star copolymers were isolated and their self-assembly in the presence of water studied.

An optimized RGD-decorated micellar drug delivery system for albendazole for the treatment of ovarian cancer: from RAFT polymer synthesis to cellular uptake

Block copolymers were prepared via RAFT polymerization with P(PEGMEMA) as the hydrophilic block to form micelles for the controlled delivery of ABZ. The group contribution method was used to estimate the partial solubility parameters for ABZ and various polymers as potential core-forming block to achieve optimum compatibility. Different ratios between MMA and LMA, a non-compatible monomer, were prepared. Cytotoxicity tests revealed a high toxicity of the ABZ-loaded micelle resulting in 80% cell deaths at a micelle concentration of 10 µg · mL(-1) . Cellular uptake of micelles has been studied using fluorescently labeled micelles, showing that a large fraction of micelles is readily taken up by OVCAR-3 cells. RGD-conjugated micelles were prepared and showed an increased cellular uptake.