### Session N4: Novel Approaches Aimed at Rational Design of Functional Polymeric Materials

 Wednesday, March 7, 2007 8:00AM - 8:36AM N4.00001: Conformation -- Dependent Design of Copolymer Sequences Invited Speaker: Alexei R. Khokhlov In 1998 we have formulated the idea of design of copolymer sequences in order to achieve required functional properties of single macromolecules in the globular state. This approach was inspired by unique sophisticated functional performance of globular proteins-enzymes. In the present talk the review of the recent advances in this field will be given. A robust free-radical polymerization procedure of synthesis of copolymer macromolecules with core-shell structure in the globular state will be described. Like globular proteins, such macromolecules do not precipitate in poor solvents. Next problem is to design a catalytic activity for these molecularly dispersed objects. To this end we investigate amphiphilic substrates and catalytically active groups which possess surface activity and, thus, an authomatically attracted by globular surfaces. We show that the resulting non-specific catalytic effect can be very significant. Wednesday, March 7, 2007 8:36AM - 9:12AM N4.00002: Novel Antimicrobial Materials Invited Speaker: Gregory N. Tew Many peptides, such as the Magainins and Defensins, are amphiphilic in nature and known to fold into specific conformations responsible for their antimicrobial membrane activity. Recently, facially amphiphilic peptides built from $\beta$-amino acids have been shown to mimic both the structures as well as the biological function of natural antimicrobial peptides. The design of simple polymers and oligomers that mimic the complex structures and remarkable biological properties of proteins is an important endeavor and would provide attractive alternatives to the difficult synthesis of natural peptides. We have designed a series of facially amphiphilic molecules that capture the essential physical and biological properties of antimicrobial peptides, but are easy to prepare from inexpensive monomers. They have potent activity (single micromolar) and are active against a broad spectrum of bacteria including gram-positive and gram-negative as well as antibiotic resistant strains. They act directly on the phospholipid membrane so that molecule-membrane interacts are critically important to understand. We will discuss our recent insight on this topic including calorimetry, SAXS, and vesicle leakage data. Wednesday, March 7, 2007 9:12AM - 9:48AM N4.00003: Biosynthetic Polypeptides as Templates in Materials Design Invited Speaker: Kristi Kiick Biosynthetic routes to protein-based polymeric materials offer important opportunities for the production of well-defined macromolecular templates, owing to the control of sequence and molecular weight inherent in the biosynthesis of proteins. In particular, the biosynthesis of polypeptides with controlled presentation of functional groups in multiple positions, coupled with their subsequent chemical modification with biologically relevant ligands, will permit the production of well-defined, bioactive macromolecules that may provide insight into biological binding events in which multivalent binding is important. Modification of the well-defined macromolecules with ligands such as saccharides has application in the study of events such as toxin neutralization and mediation of the immune and inflammatory responses. In this work, alanine-rich polypeptides of both random coil and helical conformations, equipped with glutamic acid residues to impart chemical versatility, have been produced via biosynthetic strategies. Analysis via spectroscopic and calorimetric methods indicates that the polypeptides adopt helical, beta-sheet, or random-coil conformations that can be controlled with variations in temperature, pH, and salt concentration; the conformational behavior of the polypeptides is not compromised upon chemical modification with saccharides. The binding of these macromolecules to bacterial toxins has been characterized via immunochemical and spectroscopic methods; results indicate that specific architectural features of the glycopolymer scaffold cause changes in the binding of these molecules to multivalent receptors. Given the chemical flexibility in the design of such scaffolds, they can be modified with many different moieties in addition to saccharides, so multiple opportunities exist for their application in areas where control of active side chains is important, such as in biomaterials, electronic devices, and bioinorganic structures. Wednesday, March 7, 2007 9:48AM - 10:24AM N4.00004: Polyvalent Recognition of Biopolymers:The Design of Potent Inhibitors of Anthrax Toxin Invited Speaker: Ravi Kane Polyvalency -- the simultaneous binding of multiple ligands on one entity to multiple receptors on another -- is a phenomenon that is ubiquitous in nature. We are using a biomimetic approach, inspired by polyvalency, to design potent inhibitors of anthrax toxin. Since the major symptoms and death from anthrax are due primarily to the action of anthrax toxin, the toxin is a prime target for therapeutic intervention. We describe the design of potent polyvalent anthrax toxin inhibitors, and will discuss the role of pattern matching in polyvalent recognition. Pattern-matched polyvalent inhibitors can neutralize anthrax toxin in vivo, and may enable the successful treatment of anthrax during the later stages of the disease, when antibiotic treatment is ineffective. Wednesday, March 7, 2007 10:24AM - 11:00AM N4.00005: Recent Advances in the Synthesis of Polymeric Nanostructured Materials. Invited Speaker: Craig Hawker In designing polymeric materials for use in nanotechnology it rapidly becomes apparent that control over all aspects of polymer structure (molecular weight, polydispersity, number and position of functional groups, architecture, etc.) is required if these materials are to be used successfully to create nanostructures in the sub-50 nm size regime. Equally important to the rapid introduction and incorporation of these materials into devices is the development of robust and simple techniques for their synthesis. This presentation will detail recent advances in living polymerizations, Click chemistry and self-assembly strategies for the rapid and efficient synthesis of multi-functional polymeric nanostructures in applications ranging from microelectronics/storage devices to in vivo drug delivery and diagnostics.