Special Issue "Bioconjugates/Biohybrid Polymers"

Guest Editor
Dr. Helmut Schlaad
Max Planck Institute of Colloids and Interfaces, Dept. of Colloid Chemistry, Research Campus Golm, 14424 Potsdam, Germany
Website: http://www.mpikg.mpg.de/english/03-colloidChemistry/researchGroups/Schlaad/index.html
E-Mail: helmut.schlaad@mpikg.mpg.de
Phone: +49(0)331-567-9514
Fax: +49(0)331-567-9502
Interests: methods of living/controlled ionic polymerization and ring-opening polymerization of heterocycles; polymer modification, \"thio-click\" chemistry; size-exclusion chromatography; polymer colloids and films, composite materials; bioinspired structure formation of polymers, hierarchical structures, polymer complexes

Dear Colleagues,

Bioorganic-synthetic polymer conjugates, also referred to as biohybrids, are built up from biomolecules (e.g., peptide sequence, protein, sugar, polysaccharide, DNA/RNA, terpene) and synthetic polymers, aiming to combine the advantageous properties of the two components, namely biological function, molecular recognition, chirality, etc. (biological component) and solution properties, processability, etc. (synthetic component). Although the first bioconjugate polymers have already been reported more than 40 years ago, it still remains a challenge to produce well-defined samples on larger scale. This goal has recently been approached with the developments of “living”/controlled polymerization techniques and improved coupling techniques, i.e., PEGylation and “click” chemistry.

This special issue is intended to highlight recent advances in the controlled synthesis and characterization of bioconjugate polymers as well as their use in the biomedical field (drug delivery/targeting, diagnostics, etc.), supramolecular and colloid science, materials science, and so on.

Dr. Helmut Schlaad
Guest Editor

• bioconjugate/biohybrid
• polymers
• peptide/protein
• sugar/saccharide
• DNA/RNA
• terpene
• synthesis and characterization
• structure formation
• applications

Type: Review
Title: Well-defined Glycopolymers from Reversible-deactivation Radical Polymerization
Authors: Luca Albertin, et al.
Affiliation: Centre National de la Recherche Scientifique, 601 rue de la Chimie, Domaine Universitaire de Grenoble St. Martin d'Hères BP53, 38041 Grenoble cedex 9, France; E-Mail: luca.albertin@cermav.cnrs.fr
Abstract: Glycopolymers can be defined as synthetic polymers possessing a non-carbohydrate backbone but carrying carbohydrate moieties as pendant or terminal groups. Since the pioneering work of Horejsi et al., glycopolymers have raised an ever increasing interest as artificial materials for a number of biological and biomedical uses. This is mostly due to the expectation that polymers displaying complex functionalities (similar to those of natural glycoconjugates) might be able to mimic, or even exceed, the performance of their natural counterparts in specific applications (biomimetic approach). For instance, studies have been published on the use of glycopolymers as macromolecular drugs, drug delivery systems, cell culture substrates, stationary phase in separation problems and bioassays; responsive and catalytic hydrogels, surface modifiers, artificial tissues and artificial organ substrates. Although essential, the presence of appropriate functional groups in a glycopolymer is usually insufficient to bestow it with the biological and physicochemical properties required by a given application. In fact, control of the macromolecular architecture has proved essential to enable sophisticated functions and to allow a precise correlation between these functions and the polymer structure. For this reason, in the past decade a trend has emerged in which more and more polymer chemists have engaged in the synthesis of novel glycopolymers via both traditional and precise polymerization techniques; while at the same time a greater number of biochemists and carbohydrate chemists have approached the problems related to polymer synthesis. A number of review articles on the synthesis of glycopolymers at large have already been published. Here we will focus on reversible-deactivation radical polymerization techniques since they are generally tolerant of a variety of functional groups and afford well-defined materials (that is to say uniform glycopolymers with a predetermined molecular weight and a controlled architecture) and enable surface functionalization.

Type of Paper: Article
Title: Chemical Controlled Release of Volatile Bioactives from Maleic Anhydride-styrene Random Copolymers
Authors: Damien Berthier and Andreas Herrmann
Affiliation: FIRMENICH SA, Route des Jeunes, 1 CH-1211 Geneva 8, Switzerland
Abstract: Volatile alpha,beta-unsaturated ketones were modified with cysteamine as a precursor. This precursor was then grafted onto a maleic anhydride unit of its random copolymer with styrene. The resulting copolymer was additionally labeled with fluorescent 1-pyrene methylamine. The copolymer was dispersed in a surfactant emulsion and then diluted to be deposited onto a fabric srface. The  deposition of the copolymer was measured by fluorescence spectroscopy. The release of the alpha,beta-unsaturated ketone from the copolymer into the air was measured by dynamic headspace analysis on a cotton surface. The stability of the copolymer in the surfactant emulsion was estimated by GC.

Type of Paper: Article
Title: Binding Characteristic of Ionic liquid on Bovine Serum Albumin
Authors: Yuanhua Ding, Tuosu Dai, Shuang Hao and Rong Guo
Affiliation: School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China; E-Mail: guorong@yzu.edu.cn
Abstract: In recent years, ionic liquids (ILs) are attracting a great deal of attention due to their excellent chemical and physical properties, and thus a burst of research activity in the field has been centered on the application of ILs in the life science. In the present work, the UV-visible spectroscopy, fluorescence, synchronous fluorescence spectroscopy, circular dichroism spectroscopy, negative staining - transmission electron microscopy, Fourier transform infrared (FT-IR) spectroscopy, and isothermal titration calorimetry (ITC) were firstly used to investigated the interaction between ionic liquid and bovine serum albumin (BSA). The results showed that, the addition of 1-butyl-3-methylimidazolium chloride [Bmim]Cl would make the UV absorption intensity of BSA increased and also lead to fluorescence quenching; Synchronous fluorescence results suggested that [Bmim]Cl molecules mainly interact with the region which close to the tryptophan residues of BSA, making the hydrophobic structure changed; negative staining-transmission electron microscopy directly showed the change of protein structure after adding ionic liquid. From the circular dichroism it was found that the ionic liquid also produced a much stronger impact to α-helix, β-fold of BSA, which led to changes in protein secondary structure. Finally, the formation of ionic liquid–protein complexes was driven by both the electrolytic attraction and hydrophobic association.
Keywords: ionic liquid-protein complex; binding behavior; structure