Biomacromolecular Characterizations Using State-of-the-Art Quartz Crystal Microbalance with Dissipation

Biomolecular characterization is essential in fields such as drug discovery, glycomics, and cell biology. This feature article focuses on the experimental use of quartz crystal microbalance with dissipation (QCM-D) as a powerful analytical technique to probe biological events ranging from biomacromolecular interactions and conformational changes of biomacromolecules to surface immobilization of biomacromolecules and cell morphological changes.

Metallo-polyelectrolytes as a class of ionic macromolecules for functional materials

The fields of soft polymers and macromolecular sciences have enjoyed a unique combination of metals and organic frameworks in the name of metallopolymers or organometallic polymers. When metallopolymers carry charged groups, they form a class of metal-containing polyelectrolytes or metallo-polyelectrolytes. This review identifies the unique properties and functions of metallo-polyelectrolytes compared with conventional organo-polyelectrolytes, in the hope of shedding light on the formation of functional materials with intriguing applications and potential benefits. It concludes with a critical perspective on the challenges and hurdles for metallo-polyelectrolytes, especially experimental quantitative analysis and theoretical modeling of ionic binding.

Cationic Metallo-Polyelectrolytes for Robust Alkaline Anion-Exchange Membranes

Chemically inert, mechanically tough, cationic metallo-polyelectrolytes were conceptualized and designed as durable anion-exchange membranes (AEMs). Ring-opening metathesis polymerization (ROMP) of cobaltocenium-containing cyclooctene with triazole as the only linker group, followed by backbone hydrogenation, led to a new class of AEMs with a polyethylene-like framework and alkaline-stable cobaltocenium cation for ion transport. These AEMs exhibited excellent thermal, chemical and mechanical stability, as well as high ion conductivity.

Metallocene-Containing Homopolymers and Heterobimetallic Block Copolymers via Photoinduced RAFT Polymerization

We report the synthesis of cationic cobaltocenium and neutral ferrocene containing homopolymers mediated by photoinduced reversible addition-fragmentation chain transfer (RAFT) polymerization with a photocatalyst fac-[Ir(ppy)3]. The homopolymers were further used as macromolecular chain transfer agents to synthesize diblock copolymers via chain extension. Controlled/"living" feature of photoinduced RAFT polymerization was confirmed by kinetic studies even without prior deoxygenation. A light switch between ON and OFF provided a spatiotemporal control of polymerization.

Metal-containing and related polymers for biomedical applications

A survey of the most recent progress in the biomedical applications of metal-containing polymers is given. Due to the unique optical, electrochemical, and magnetic properties, at least 30 different metal elements, most of them transition metals, are introduced into polymeric frameworks for interactions with biology-relevant substrates via various means. Inspired by the advance of metal-containing small molecular drugs and promoted by the great progress in polymer chemistry, metal-containing polymers have gained momentum during recent decades. According to their different applications, this review summarizes the following biomedical applications: (1) metal-containing polymers as drug delivery vehicles; (2) metal-containing polymeric drugs and biocides, including antimicrobial and antiviral agents, anticancer drugs, photodynamic therapy agents, radiotherapy agents and biocides; (3) metal-containing polymers as biosensors, and (4) metal-containing polymers in bioimaging.

Enzyme-responsive polymer hydrogels for therapeutic delivery

Enzymes play a central role in a spectrum of fundamental physiological processes and their altered expression level has been associated with many diseases and pathological disorders. Enzymes therefore can be exploited as a pristine biological trigger to tune material responses and to achieve controlled release of biomolecules at desired sites. This mini-review highlights enzyme-responsive polymer hydrogels for therapeutic delivery applications developed within the last five years, focusing on protease- and glycosidase-based catalyzed reactions. Strategies employed to produce responsive materials are described. Successful applications for controlled drug delivery are highlighted, and finally, future opportunities and challenges are presented.

A copolymer capsule with a magnetic core for hydrophilic or hydrophobic drug delivery via thermo-responsive stimuli or carrier biodegradation

The glutathione-triggered and thermal-responsive polymer microcapsule carrier with magnetic core, Fe₃O₄@capsule is prepared for controlled release of hydrophilic or hydrophobic drug molecules.