Synthesis and Biological Evaluation of a Degradable Trehalose Glycopolymer Prepared by RAFT Polymerization

Abstract

There is a significant need for new biodegradable protein stabilizing polymers. Herein, the synthesis of a polymer with trehalose side chains and hydrolytically degradable backbone esters and its evaluation for protein stabilization and cytotoxicity are described. Specifically, an alkene-containing parent polymer is synthesized by reversible addition-fragmentation chain transfer polymerization, and thiolated trehalose is installed using a radical-initiated thiol-ene reaction. The stabilizing properties of the polymer are investigated by thermally stressing granulocyte colony-stimulating factor (G-CSF), which is expressed and purified using a custom-designed G-CSF fusion protein with a polyhistidine-tagged maltose binding protein. The degradable polymer is shown to stabilize G-CSF to 66% after heating at 40 °C. Poly(5,6-benzo-2-methylene-1,3-dioxepane (BMDO)-co-butyl methacrylate-trehalose) is degraded and its cellular compatibility is investigated. While the polymer is noncytotoxic, cytotoxic effects are observed from the degraded products in fibroblasts and murine myeloblasts. These data provide important information for future use of BMDO-containing trehalose glycopolymers for biomedical applications.

Ice recrystallisation inhibiting polymers prevent irreversible protein aggregation during solvent-free cryopreservation as additives and as covalent polymer-protein conjugates

“…Maynard has developed trehalose side-chain polymers for protein protection during lyophilization. A range of trehalose-polymers (poly(4,6- O -(4-vinylbenzylidene)-α,α-trehalose), polymers of α,α-trehalose modified with a styrenyl acetal, methacrylate acetal, styrenyl ether, or a methacrylate, and poly(5,6‐benzo‐2‐methylene‐1,3‐dioxepane (BMDO)‐ co ‐butyl methacrylate‐trehalose)) have been synthesized and shown to be very potent stabilizers when applied as polymer-protein conjugates [31] , [32] , [33] . However, the conjugation process itself does result in loss of activity relative to the free protein alone, so the benefit of free polymer at higher concentrations, verses conjugated at lower must be considered, and any new polymer requires safety and approval processes for biomedical applications.…”

Tailor-made glycopolymersviareversible deactivation radical polymerization: design, properties and applications

“…In addition to the azide–alkyne “click chemistry”, the use of thiol–ene “click chemistry” is very popular for the introduction of sugar moieties in the polymer chain via post-modification. 30,44,133,134 The thiol–ene reactions are extremely fast and have high tolerance against a wide range of reaction conditions and functional groups. 135 Importantly, under biological conditions, the thioglycosidic linkage of the sugar units are more stable against enzymatic degradation as compared to the O -glycosidic linkages.…”

“…polymerization of an activated monomer followed by post-functionalization with sugar moieties. 28–30 Conventional free radical polymerization (FRP) is a well-established technique for the synthesis of glycopolymers due to its robustness, cost-effectiveness, and tolerance to a wide range of reaction conditions. However, the disadvantages associated with FRP, such as uncontrolled molecular weights and very broad dispersity ( Đ > 2.0) due to the uncontrolled polymerization rate and poor control over terminal functionalities as well as the macromolecular architecture, encouraged the discovery of reversible-deactivation radical polymerization (RDRP).…”

Cathepsin B-responsive and gadolinium-labeled branched glycopolymer-PTX conjugate-derived nanotheranostics for cancer treatment

“…For example, polymers with saccharide groups (glycopolymers) have excellent biocompatibility and water-solubility, and these glycopolymers may act as carriers to deliver hydrophobic therapeutic agents 23 , 24 , 25 . Since the glycopolymer with a controllable MW and a low dispersive coefficient can be synthetized via reversible addition-fragmentation chain transfer (RAFT) polymerization 26 , anti-cancer drugs and imaging probes may be conjugated with the glycopolymer, resulting in a multifunctional glycopolymer-based drug delivery system 27 .…”