Intrinsically permeable polymer vesicles based on carbohydrate-conjugated poly(2-oxazoline)s synthesized using a carbohydrate-based initiator system

A thermo-responsive poly(n-propyl oxazoline) block was employed as the hydrophobic segment in an amphiphilic glyco polymer. This approach affords intrinsically permeable polymer vesicles for water-soluble compounds.

The effect of linker length on ConA and DC-SIGN binding of S-glucosyl functionalized poly(2-oxazoline)s

A series of poly(2-oxazoline) based glycopolymers with different linkers were prepared via thiol–ene click reaction and cationic ring opening reaction. The binding of these polymers to lectins were studied.

Substituted Polyesters by Thiol-Ene Modification: Rapid Diversification for Therapeutic Protein Stabilization

Many proteins, especially those used as therapeutics, are unstable to storage and shipping temperatures, leading to increased costs in research and industry. Therefore, the design and synthesis of novel stabilizers is an important area of investigation. Herein we report new degradable polymers that stabilize proteins to environmental stressors such as refrigeration and elevated temperature. Specifically, polycaprolactones with different pendant groups were synthesized and surveyed for their ability to stabilize an important therapeutic protein to storage and shipping conditions. Ring-opening polymerization (ROP) of an allyl-substituted caprolactone monomer was carried out using the organocatalyst 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) to yield a well-defined, alkene-substituted degradable polymer, which was used as a common backbone to control for the degree of polymerization. Relevant side chains such as trehalose, lactose, glucose, carboxybetaine, and oligo(ethylene glycol) were installed via postpolymerization thiol-ene reactions. These degradable polymers were then employed as excipients for the stabilization of the therapeutic protein granulocyte colony-stimulating factor (G-CSF) against storage at 4 °C and shipping temperatures of 60 °C. The best stabilization was observed using the trehalose- and zwitterion- substituted polyesters. Both the trehalose- and carboxybetaine-substituted pCL were further investigated with regard to molecular weight dependence, and it was found that the molecular weight was minimally important for stabilization to refrigeration, but critical for G-CSF stabilization at elevated temperatures. Both high performing zwitterionic and trehalose polyesters were also degraded, and the polymers and degradation products were shown to be noncytotoxic. This work provides potential biocompatible polymers for stabilization of the important therapeutic G-CSF, as well as a general platform for the future discovery of new polymeric protein stabilizers.

Synthesis of Glycopolymer Containing Cell-Penetrating Peptides as Inducers of Recombinant Protein Expression under the Control of Lactose Operator/Repressor Systems

We recently reported on newly synthesized S-galactosyl oligo(Arg) conjugates to overcome the serious problem of the passage through the E. coli cell membrane. Following in vivo expression of green fluorescent protein (GFP) induced by each of the S-galactosyl (Arg)n constructs (n = 5, 6, 8) at the T5 promoter in E. coli for 18 h, we visually observed that the cultures fluoresced green light when excited with UV light. The fluorescence intensities for these cultures were greater than that found for a control culture, indicating that the peptides had induced GFP expression. In order to accomplish higher expression efficiency, we investigated the cluster effect and structural fine-tuning of new poly(2-oxazoline) containing CysArgArg as the cell-penetrating peptide (CPP) and S-galactosides when acting as inducers of recombinant protein expression under the control of lac operator/repressor systems in this article. Quantitative fluorescence intensities (calculated per molecule) also supported the observations that the cell-penetrating glyco poly(2-oxazoline)s were better inducers of GFP expression than glyco poly(2-oxazoline) containing no CPP or isopropyl β-d-thiogalactoside. Because the level of GFP expression was directly related to the number of sugar residues in each glyco poly(2-oxazoline), we propose that a cluster effect of the S-galactosides attached to the cell-penetrating poly(2-oxazoline) is responsible for how well the galactosides inhibited the lac repressor to activate the protein expression under the control of the lac operator/repressor system. A similar tendency was observed when the T7 promoter was placed upstream of the gene for an artificial extracellular matrix protein and glyco poly(2-oxazoline)s-CPP conjugates were used as inducers. To assess how the glyco poly(2-oxazoline) penetrate the cell membrane, we labeled the glyco poly(2-oxazoline) using 1-amino pyrene and directly observed the penetration process. Furthermore, we could visualize protein expression under the control of a lac promoter/operator/repressor system using transmission electron microscopy combined with energy dispersive X-ray analysis mapping.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010

This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.