Darrin Pochan

Darrin Pochan

Professor and Chair

Department of Materials Science and Engineering

Email : pochan@udel.edu
Phone : (302) 831-3569
201C DuPont Hall

Biosketch

Dr. Pochan`s group is exploring vesicle, micelle and hydrogel formation in dilute aqueous systems of block polypeptides. This work is coupled with solid-state block polypeptide characterization and block polypeptide-protein blend morphology studies to establish the self-assembly rules for these novel synthetic materials. In addition, Dr. Pochan is studying the self-assembly of unique polymeric and organic-inorganic hybrid materials in bulk and for pattern formations in thin films. Other research interests focus on novel bulk structure and pattern formation via competing phase transitions in hybrid dentritic/linear polymer materials. Experimental techniques frequently used include small and wide angle x-ray and neutron scattering, transmission and scanning electron microscopy, and atomic force microscopy.

Awards

  • Named Fellow of the American Chemical Society, PMSE Division, 2013
  • Named NextPower Distinguished Chair Professor,
  • National Tsing Hua University, Taiwan, 2012
  • Named Fellow of the American Physical Society, 2011
  • John H. Dillon medal, Division of Polymer Physics, American Physical Society, 2007
  • College of Engineering Outstanding Young Faculty Award, University of Delaware, 2006
  • Named Fellow of the Royal Society of Chemistry, 2005
  • NSF Career award, 2004 – 2009
  • DuPont Young Professor Grant, 2002 – 2005 (one of 8 total nationally, 13 total internationally)
  • Chair of 2009 Macromolecular Materials Gordon Research Conference
  • Appointed as Associate Editor for North America of Soft Matter published by the Royal Society of Chemistry, U.K., 2005.

Research Interests

Biopolymer Nanocomposites

The addition of small amounts of clay platelet filler to a polymer matrix greatly enhances many chemical and mechanical material properties of the matrix polymer. This well-developed area of materials science and engineering is producing new materials in diverse areas such as engineering thermoplastics and robust polymer-based batteries. Our interest in nanocomposites is to produce strong, robust materials using biopolymers as the matrix material and using assembled, fibrillar peptide nanostructures as the reinforcement phase.. Strong materials can then be produced with inherent bioproperties (biocompatibility, biodegradability, antimicrobial) due to the completely biomolecular nature of the material.

Biopolymer single crystal growth and characterization

In order to directly observe the effects of complicated environments on polymer crystallization, we solution grow and characterize single crystals of the polymer used in nanocomposites and responsive hydrogel formation and the oligopeptides used in responsive hydrogel formation. Only by characterizing the single crystal structure of the different molecules can one begin to elucidate the effects of more complicated phases (bulk state, thin films) and mixtures (nanocomposite formation) on the crystallization of the biomolecules. The crystallinity, both extent and morphology of, plays a significant role in the ultimate material properties of the systems studied.

Directed magnetic nanoparticle assembly with silk-like peptides

Silk-like biopolymers are being studied as directed self-assembly agents for mixtures with magnetic materials. The self-assembly behavior of the polypepetides causes the directly assembly of the magnetic materials to produce nanocomposites with desired superlattice structure and consequent magnetic properties. The synthetic proteins are silk-like in sequence and the magnetic nanoparticles are currently based on gadolinium and dysprosium.

Hydrogel formation via block copolypeptide self-assembly

Amphiphilic block copolypeptides are designed with desired charge character and secondary structure in order to self-assemble in aqueous solution. The final material formed is a dilute but rigid hydrogel (rigid gels are formed down to ~0.5 wt% polypeptide) with several important innate properties such as both nanoscale and microscale porosity (important for potential tissue engineering applications), shear thinning rheological behavior (easily processed into a desired geometry) with a quickly recovering modulus on cessation of shear, and mechanical properties (shear moduli) that are dependent on molecular secondary structure. New designs take advantage of the peptidic chemistry of the assemblers to build in specific biofunctionality (cell binding sites, growth factors) in the hydrogels.

One, two, and three dimensional superstructured materials based on polymeric nanoparticles

This interdisciplinary project involves polymer chemistry, surface science, inorganic/organic cocrystallization, rheology, and material morphology characterization. The research approach involves the systematic ordering, in solution and on substrates, of crosslinked assemblies of copolymers, as robust, nanoscale building blocks having complex structure and composition. These assemblies are being studied as potentially leading to a diverse set of technologies such as read-write memory arrays and well-defined substrates for controlled nucleation and growth of inorganic and biomolecular crystals. The morphology of individual polymer nanoparticles and final hybrid assemblies and the assembly process are the primary focus at UD.

Responsive materials constructed via peptide folding and conseqent self-assembly

Oligopeptides are designed to intramolecularly fold in response to a desired environmental cue. After folding, self-assembly into a desired structure/material occurs. Importantly, by linking peptide folding with self-assembly , material formation is completely reversible providing for materials with properties responsive to the environment surrounding them. This interdisciplinary work involves peptide design through materials characterization. The first examples of responsive materials are extremely dilute but rigid hydrogels completely reversible with pH and temperature.

Vesicle and micelle formation via non-ionic, amphiphilic block copolypeptide self-assembly

Amphiphilic block copolypeptides are designed with PEGylated, nonionic hydrophilic blocks and hydrophobic blocks with varying secondary structure. These molecules are robust membrane and micelle formers in aqueous solution. Molecular parameters (e.g. relative block length, block secondary structure) are chosen in an effort to design a priori a desired assembly shape and size. These designed assemblies hold promise in the areas of drug and cell delivery.

Representative Publications

Zhu, J.; Zhang, S.; Zhang, F.; Wooley, K.L.; Pochan, D.J. “Hierarchical assembly of complex block copolymer nanoparticles into multicompartment superstructures through tunable inter-particle associations,” Advanced Functional Materials, 2012, 23, 1767–1773.

Zhang, S.; Zou, J.; Zhang, F.; Elsabahy, M.; Felder, S.; Zhu, J.; Pochan, D.J.; Wooley, K.L. “Rapid and versatile construction of diverse and functional nanostructures derived from a polyphosphoesterbased bio-mimetic block copolymer system,” Journal of the American Chemical Society, 2012, 134,18467-18474

Ikeda, M.; Ochi, R.; Kurita, Y.; Pochan, D.J.; Hamachi, I. “Heat-Induced Morphological Transformation of Supramolecular Nanostructures by Retro-Diels-Alder Reaction,” Chemistry-A European Journal, 2012, 18, 13091-13096.

Pochan, D.J. “Approaching Asymmetry and Versatility in Polymer Assembly,” Science, 2012, 337, 530-531.

Ogunsola, O.A.; Kraeling, M.E.; Zhong, S.; Pochan, D.J.; Bronaugh, R.L.; RAghavan, S.R. Structural Analysis of “Flexible” Liposome Formulations: New Insights into the Skin-Penetrating Ability of Soft Nanostructures,” Soft Matter, 2012, 8, 10226-10232.

Xiao, L.; Zhu, J.; Londono, J.D.; Pochan, D.J.; Jia, X. “Mechano-responsive hydrogels crosslinked by block copolymer micelles,” Soft Matter, 2012, 8, 10233 – 10237.

Yan, C.; Mackay, M.E.; Czymmek, K.; Nagarkar, R.P.; Schneider, J.P.; Pochan, D.J. “Injectable Solid Peptide Hydrogel as a Cell Carrier: Effects of Shear Flow on Hydrogels and Cell Payload,” Langmuir, 2012, 28, 6076-6087.

Krishna, O.D.; Wiss, K.T.; Luo, T.; Pochan, D.J.; Theato, P.; Kiick, K.L. “Morphological Transformations in a Dually Thermoresponsive Coil-Rod-Coil Bioconjugate,” Soft Matter, 2012, 8, 3832-3840.

Knerr, P.J.; Branco, M.C.; Nagarkar, R.; Pochan, D.J.; Schneider, J.P. “Heavy Metal Ion Hydrogelation of a Self-assembling Peptide via Cysteinyl Chelation,” Journal of Materials Chemistry, 2012, 22, 1352-1357.

Giano, M.; Jin, A.; Pochan, D.; Schneider, J. “Controlled biodegradation of Self-assembling betahairpin Peptide hydrogels by proteolysis with matrix metalloproteinase-13,” Biomaterials, 2011, 32. 6471-6477.

Nagy, K.; Giano, M.; Jin, A.; Pochan, D.; Schneider, J. “Enhanced Mechanical Rigidity of Hydrogels Formed From Enantiomeric Peptide Assemblies,” Journal of the American Chemical Society, 2011, 133, 14975-14977.

Meeuwissen, S.A.; Kim, K.T.; Chen, Y.; Pochan, D.J.; van Hest, J.C.M. “Controlled Shape Transformation of Polymersome Stomatocytes,” Angewandte Chemie-Int Ed., 2011, 50, 7070-7073.

Top, A.; Roberts, C.; Pochan, D.J.; Kiick, K.L. “Controlling assembly of helical polypeptides via PEGylation strategies,” Soft Matter, 2011, 7, 9758-9766.

Altunbas, A.; Lee, S.J.; Rajasekaran, S.A.; Schneider, J.P.; Pochan, D.J. “Encapsulation of Curcumin in Self-Assembling Peptide Hydrogels as Injectable Drug Delivery Vehicles,” Biomaterials, 2011, 32, 5906-5914. NIHMSID292626

Micklitsch, C.M.; Knerr, P.J.; Branco, M.C.; Nagarkar, R.; Pochan, D.J.; Schneider, J.P. “ZincTriggered Hydrogelation of a Self-Assembling beta-Hairpin Peptide,” Angewandte Chemie-Int. Ed., 2011, 50, 1577-1579.

Lin, L.Y.; Lee, N.S.; Zhu, J.; Nystrom, A.M.; Pochan, D.J.; Dorshow, R.B.; Wooley, K.L. “Tuning core vs. shell dimensions to adjust the performance of nanoscopic containers for the loading and release of doxorubicin,” Journal of Controlled Release, 2011, 152, 37-48.

Greene, A.C.; Zhu, J.H.; Pochan, D.J.; Jia, X.Q.; Kiick, K.L. “Poly(acrylic acid-b-styrene) Amphiphilic Multiblock Copolymers as Building Blocks for the Assembly of Discrete Nanoparticles,” Macromolecules, 2011, 44, 1942-1951.

Wang, X.Y.; Gurski, L.A.; Zhong, S.; Xu, X.A.; Pochan, D.J.; Farach-Carson, M.C.; Jia, X.Q. “Amphiphilic Block Co-polyesters Bearing Pendant Cyclic Ketal Groups as Nanocarriers for Controlled Release of Camptothecin,” Journal of Biomaterials Science-Polymer Edition, 2011, 22, 1275-1298.

Grieshaber, S.E.; Nie, T.; Yan, C.; Zhong, S.; Teller, S.S.; Clifton, R.J.; Pochan, D.J.; Kiick, K.L.; Jia, X. “Assembly Properties of Alanine-Rich, Lysine-Containing Peptide and the Formation of Peptide/Polymer Hybrid Hydrogels,” Macromol. Chem. Phys., 2011, 212, 229-239.

Pochan, D.J.; Zhu, J.H.; Zhang, K.; Miesch, C.; Emrick, T.S.; Wooley, K.L.“Multicompartment and Multigeometry Nanoparticle Assembly,” Soft Matter, 2011, 7, 2500 – 2506

Bartels, J. W.; Cauet, S. I.; Billings, P. L.; Lin, L. Y.; Zhu, J. H.; Fidge, C.; Pochan, D. J.; Wooley, K. L. Evaluation of Isoprene Chain Extension from PEO Macromolecular Chain Transfer Agents for the Preparation of Dual, Invertible Block Copolymer Nanoassemblies. Macromolecules, 2010, 43, 7128- 7138.

Yu, X. F.; Zhong, S.; Li, X. P.; Tu, Y. F.; Yang, S. G.; Van Horn, R. M.; Ni, C. Y.; Pochan, D. J.; Quirk, R. P.; Wesdemiotis, C.; Zhang, W. B.; Cheng, S. Z. D., A Giant Surfactant of Polystyrene- (Carboxylic Acid-Functionalized Polyhedral Oligomeric Silsesquioxane) Amphiphile with Highly 4 Stretched Polystyrene Tails in Micellar Assemblies. Journal of the American Chemical Society, 2010, 132, 16741-16744.

Kim, K. T.; Zhu, J. H.; Meeuwissen, S. A.; Cornelissen, J.; Pochan, D. J.; Nolte, R. J. M.; van Hest, J. C. M., Polymersome Stomatocytes: Controlled Shape Transformation in Polymer Vesicles. Journal of the American Chemical Society, 2010 132, 12522-12524.

Yan, C. Q.; Altunbas, A.; Yucel, T.; Nagarkar, R. P.; Schneider, J. P.; Pochan, D. J., Injectable solid hydrogel: mechanism of shear-thinning and immediate recovery of injectable beta-hairpin peptide hydrogels. Soft Matter, 2010, 6, 5143-5156. PMCID: PMC3091287

Yan, C. Q.; Pochan, D. J., Rheological properties of peptide-based hydrogels for biomedical and other applications. Chemical Society Reviews, 2010, 39, 3528-3540. NIHMS291439

Xiao, L. X.; Liu, C.; Zhu, J. H.; Pochan, D. J.; Jia, X. Q., Hybrid, elastomeric hydrogels crosslinked by multifunctional block copolymer micelles. Soft Matter, 2010, 6, 5293-5297. PMCID: PMC3027150

Branco, M. C.; Pochan, D. J.; Wagner, N. J.; Schneider, J. P., The effect of protein structure on their controlled release from an injectable peptide hydrogel. Biomaterials, 2010, 31, 9527-9534. PMCID: PMC2976777

Rughani, R. V.; Branco, M. C.; Pochan, D.; Schneider, J. P., De Novo Design of a Shear-Thin Recoverable Peptide-Based Hydrogel Capable of Intrafibrillar Photopolymerization. Macromolecules, 2010, 43, 7924-7930.

Sharma, N.; McKeown, S. J.; Ma, X.; Pochan, D. J.; Cloutier, S. G., Structure-Property Correlations in Hybrid Polymer-Nanoparticle Electrospun Fibers and Plasmonic Control over their Dichroic Behavior. Acs Nano, 2010, 4, 5551-5558.

Hayward, R.C. and Pochan, D.J. “Tailored Assemblies of Block Copolymers in Solution: It is All about the Process,” Macromolecules, 2010, 8, 3577-3584

Katz, J.S.; Zhong, S.; Ricart, B.G. Pochan, D.J.; Hammer, D.A.; Burdick, J.A. “Modular Synthesis of Biodegradable Diblock Copolymers for Designing Functional Polymersomes.” JACS, 2010, 132, 3654+. PMCID: PMC2856336

Nagarkar, R.P.; Hule, R.A.; Pochan, D.J.; Schneider, J.P. “Domain Swapping in Materials Design.” Biopolymers, 2010, 94, pp 141-155. PMID: 20091872

Sharma, N.; Jaffari, G.H.; Shah, S.I.; Pochan, D.J. “ Orientation-dependent magnetic behavior in aligned nanoparticle arrays constructed by coaxial electrospinning,” Nanotechnology, 2010, vol 21, Article Number: 085707).

Zhong, S.; Pochan, D.J. “Cryogenic transmission electron microscopy for direct observation of polymer and small molecule materials and structures in solution,” Polymer Reviews, 2010, 50, 287- 320.

Altunbas, A.; Sharma, N.; Lamm, M.S.; Yan, C.; Nagarkar, R.P.; Schneider, J.P.; Pochan, D.J. “Peptide-Silica Hybrid Networks: Biomimetic Control of Network Mechanical Behavior,” ACS Nano, 2009, 4, 181-188. PMCID: 20028097

Salick, D.A.; Pochan, D.J.; Schneider, J.P. “Design of an Injectable beta-Hairpin Peptide Hydrogel That Kills Methicillin-Resistant Staphylococcus aureus,” Advanced Materials, 2009, 21, 4120+.

Sharma, N.; Top, A.; Kiick, K.L.; Pochan, D.J. “One-Dimensional Gold Nanoparticle Arrays by Electrostatically Directed Organization Using Polypeptide Self-Assembly,” Angewandte Chemie, 2009, 48, 7078-7082.

Rajagopal, K.; Lamm, M.S.; Haines-Butterick, L.A.; Pochan, D.J.; Schneider, J.P. “Tuning the pH Responsiveness of beta-Hairpin Peptide Folding, Self-Assembly, and Hydrogel Material Formation,” Biomacromolecules, 2009, 10, 2619-2625.

Pochan, D.J. “Soft Matter: Spots and Stripes,” Nature Materials, 2009, 8, 773-774.

Hamley, I.W.; Krysmann, M.J.; Kelarakis, A.; (Castelletto, V.; Noirez, L.; Hule, R. A.; Pochan, D. J. “Nematic and Columnar Ordering of a PEG-Peptide Conjugate in Aqueous Solution,” Chemistry-A European Journal, 2008, 14, 11268-.

Amir, R.J.: Zhong, S.; Pochan, D.J.; Hawker, C.J. “Enzymatically Triggered Self-Assembly of Block Copolymers,” Journal Of The American Chemical Society, 2009, 131, 13949-.

Hule, R.A.; Nagarkar, R.; Hammouda, B.; Schneider, J.P.; Pochan, D.J. “Dependence of SelfAssembled Peptide Hydrogel Network Structure on Local Fibril Nanostructure,” Macromolecules, 2009, 2, 7137-7145. PMCID: PMC3091019

Branco, M.C.; Nettesheim, F.; Pochan, D.J.; Schneider, J.P; Wagner, N.J. “Fast Dynamics of Semiflexible Chain Networks of Self-Assembled Peptides,” Biomacromolecules, 2009, 10, 1374- 1380.

Rughani, R.V.; Salick, D.A.; Lamm, M.A.; Yucel, T.; Pochan, D.J.; Schneider, J.P. “Folding, Selfassembly and Bulk Material Properties of a De Novo Designed Three-Stranded β-sheet Hydrogel,” Biomacromolecules, 2009, 10, 1295-1304.

Jha, A.K.; Hule, R.A.; Jiao, T.; Teller, S.S.; Clifton, R.J.; Duncan, R.L.; Pochan, D.J.; Jia, X.Q. “Structural Analysis and Mechanical Characterization of Hyaluronic Acid-Based Doubly CrossLinked Networks,” Macromolecules, 2009, 42, 537-546.

Kratz, K.; Breitenkamp, K.; Hule, R.; Pochan, D.; Emrick, T. “PC-Polyolefins: Synthesis and Assembly Behavior in Water,” Macromolecules, 2009, 42, 3227-3229.

Cui, H.; Chen, Z.; Wooley, K.L.; Pochan, D.J. “Origins of toroidal micelle formation through charged triblock copolymer self-assembly,” Soft Matter, 2009, 5, 1269 – 1278.

Castelletto, V.; Hamley, I.W.; Hule, R.A.; Pochan, D. “Helical-Ribbon Formation by a beta-Amino Acid Modified Amyloid beta-Peptide Fragment,” Angewandte Chemie-International Ed., 2009, 48, 2317-2320.

Branco M.C.; Pochan D.J.; Wagner N.J.; Schneider J.P. “Macromolecular diffusion and release from self-assembled beta-hairpin peptide hydrogels.” Biomaterials. 2009, 7, 1339-47.

Haines-Butterick, L.A.; Salick, D.A.; Pochan, D.J.; Schneider, J.P. “In vitro assessment of the pro- inflammatory potential of b-hairpin peptide hydrogels” Biomaterials, 2008, 29, 4164–4169. PMCID: PMC2645339 6 51) Hule, R.A.; Nagarkar, R.P.; Altunbas, A.; Rama

Hule, R.A.; Nagarkar, R.P.; Altunbas, A.; Ramay, H.R.; Branco, M.C.; Schneider, J.P.; Pochan, D.J. “Correlations between structure, material properties and bioproperties in self-assembled -hairpin peptide hydrogels,” Faraday Discussions, 2008, 139, 251-264.

Yucel, T.; Micklitsch, C.; Schneider, J.P.; Pochan, D.J. “Direct Observation of Early-Time Hydrogelation in β-Hairpin Peptide Self-Assembly,” Macromolecules, 2008, 41, 5763 – 5772

Krysmann, M.J.; Kelarakis, A.; Castelletto, V.; Noirez, L.; Hule, R.A.; Pochan. D.J.; Hamley, I.W. “Nematic & Columnar Ordering of a PEG-Peptide Conjugate in Aqueous Solution,” Chemistry: A European Journal, 2008, 14, 11369 – 11375.

Hales, K.; Chen, Z.; Wooley, K.L.; Pochan, D.J. “Nanoparticles with tunable internal structure from charged triblock copolymer self-assembly,” Nano Letters, 2008, 8, 2023 – 2026

Krysmann M.J.; Castelletto, V.; Kelarakis, A.; Hule, R.A.; Pochan, D.J.; Hamley, I.W. “Selfassembly and hydrogelation of an amyloid peptide fragment,” Biochemistry, 2008, 47, 4597-4605.

Nagarkar, R.; Hule, R.A.; Pochan, D.J.; Schneider, J.P. “De Novo Design of Strand-Swapped betaHairpin Hydrogels,” Journal of the American Chemical Society, 2008, 130, 4466-74.

Zhong, S.; Cui, H.; Chen, Z.; Wooley, K.L.; and Pochan, D.J. “Helix self-assembly through the coiling of cylindrical micelles,” Soft Matter, 2008, vol. 4, pp. 90-93.

Salick, D.A.; Kretsinger, J.K.; Pochan, D.J.; Schneider, J.P. “Inherent Antibacterial Activity of a Peptide-Based -Hairpin Hydrogel,” J. Am. Chem. Soc., 2007, 129, 14793-9.

Pressly, E.D.; Rossin, R.; Hagooly, A.; Fukukawa, K.; Messmore, B.W.; Welch, M.J.; Wooley, K.L.; Lamm, M.; Hule, R.; Pochan, D.; Hawker, C.J. “Structural Effects on the Biodistribution and PET Imaging of Well-defined 64Cu-Labeled Nanoparticles Comprised of Amphiphilic Block Graft Copolymers,” Biomacromolecules, 2007; 8; 3126-3134.

Ozbas, B.; Rajagopal, K.; Haines-Butterick, L.; Schneider, J.P., Pochan, D.J. “Reversible Stiffening Transition in β-Hairpin Hydrogels Induced by Ion Complexation,” Journal of Physical Chemistry, 2007, 111, 13901-8.

Lamm, M.S.; Sharma, N.; Beyer, F.L.; Schneider, J.P.; Pochan, D.J. “Laterally Spaced Linear Nanoparticle Arrays Templated by Laminated β-Sheet Fibrils,” Advanced Materials, 2008, 20, 447- 451.

Cui, H.; Chen, Z.; Zhong, S.; Wooley, K.L.; Pochan, D.J. “Advance in Structural Complexity of Block Copolymer Assembly via Kinetics Control,” Science, 2007, 317, 647-650.

Cui, H.; Hodgdon, T.K.; Kaler, E.W.; Abezgaous, L.; Danino, D.; Lubovsky, M.; Talmon, Y.; Pochan, D.J. “Elucidating the Assembled Structure of Amphiphiles in Solution via CryogenicTransmission Electron Microscopy,” Soft Matter, 2007, 3, 945-955.

Haines-Butterick, L.; Rajagopal, K.; Pilarz, M.; Lamm, M.S.; Pochan, D.J.; Schneider, J.P. “Controlling Hydrogelation Kinetics via Peptide Design for Three-Dimensional Encapsulation and Injectable Delivery of Cells,” PNAS, 2007, 104, 7791-7796. 7 65) Li, Z.; Chen, Z.; Cui, H.; Hales, K.; Wooley, K.L.;

Li, Z.; Chen, Z.; Cui, H.; Hales, K.; Wooley, K.L.; Pochan, D.J. “Controlled Stacking of Charged Block Copolymer Micelles”, Langmuir, 2007, 23, 4689-4694.

Thiel, J.; Pakstis, L.; Buzby, S.; Raffi, M.; Pochan, D.J.; Shah, S.I. “Antibacterial Properties of Silver doped Titania,” Small, 2007,3, 799-803.

Shearer, A.S.; de Miguel, Y.R.; Minich, E.A.; Pochan, D.; Jenny, C. “Polymer-supported metallocene catalysts for ethylene polymerisation: Characterisation and catalytic studies,” Inorganic Chemistry Communications, 2007, 10, 262-264.

Hule, R.; Pochan, D.J. “Polymer Nanocomposites for Biomedical Applications,’ MRS Bulletin, 2007, 32, 354-358.

Hule, R.; Pochan, D.J. “Polypeptide-Based Layered Silicate Nanocomposite: Effect of Poly-l-lysine Secondary Structure on the Physical Properties of the Hybrid,” Journal of Polymer Science, Polymer Physics, 2007, 45, 239-252.

Hales, K.E.; Pochan, D.J.; “Using Polyelectrolyte Block Copolymers to Tune Nanostructure Assembly,” Current Opinion in Colloid and Interfacial Science, 2006, 11, 330-336.

Jones, M.-C.; Tewari, P.; Blei, C.; Hales, K.; Pochan, D.J.; Leroux, J.-C. “Self-Assembled Nanocages for Hydrophilic Guest Molecules,” Journal of the American Chemical Society, 2006, 128, 14599- 14605.

Cui, H.; Chen, Z.; Wooley, K.L.; Pochan, D.J. “Controlling Micellar Structure of Amphiphilic Charged Triblock Copolymers in Dilute Solution via Co-assembly with Organic Counterions of Different Spacer Lengths,” Macromolecules, 2006, 127, 8592-8593.

C. Veerman, C.; Rajagopal, K.; Palla, C.S.; Pochan, D.J.; Schneider, J.P.; Furst, E.M. “Gelation kinetics of beta-hairpin peptide hydrogels,” Macromolecules, 2006, 39, 6608 -6614.

Ozbas, B.; Schneider, J.P.; Pochan, D.J. “Hydrogels Constructed via beta-Hairpin Peptide SelfAssembly,” chapter 20 in Advances in Biopolymers: Molecules, clusters, networks and interactions, American Chemical Society ACS Symposium Series 935, 2006, pp. 284-297.

Rajagopal, K.; Ozbas, B.; Pochan, D.J.; Schneider, J.P. “Probing the Importance of Lateral Hydrophobic Association in Self-Assembling Peptide Hydrogelators” European Biophysics Journal, 2006; 35; 162-169.

Lamm, M.; Rajagopal, K.; Schneider, J.P.; Pochan, D.J. “Laminated Morphology of Non-twisting beta sheet fibrils constructed via peptide self-assembly,” Journal of the American Chemical Society, 2005; 127, 16692-16700.

Haines, L.A.; Rajagopal, K.; Ozbas, B.; Salick, D.A.; Pochan, D.J.; Schneider, J.P. “Light Activated Hydrogel Formation via the Triggered Folding and Self-assembly of a Designed Peptide”, Journal of the American Chemical Society, 2005; 127; 17025-17029.

Guertin, R.P.; Valluzzi, R.; Haas, T.E.; Pochan, D. “Magnetically Complexed Tissue-Mimicking Peptides,” Journal of Applied Physics, 2005, 97 (10): Art. No. 10M521 Part 3. 8 79) Holowka, E.P.; Pochan, D.J.; Deming, T.J. “Charged

Holowka, E.P.; Pochan, D.J.; Deming, T.J. “Charged Polypeptide Vesicles with Controllable Diameter,” Journal of the American Chemical Society, 2005, 127, 12423-12428.

Tomczak, M.M.; Glave, D.D.; Drummy, L.; Lawrence, C.G.; Stone, M.O.; Perry, C.C.; Pochan, D.J.; Deming, T.J.; Naik, R.R. “Polypeptide Templated Synthesis of Hexagonal Silica Platelets,” Journal of the American Chemical Society, 2005, 127, 12577-12582.

Cui, H.; Krikorian, V.; Thompson, J.; Nowak, A.P.; Deming, T.J., Pochan, D.J. “Preparation and Characterization of Synthetic Polypeptide Single Crystals with Controlled Thickness,” Macromolecules, 2005, 38, 7371-7377.

Krikorian, V.; Pochan, D.J. “Crystallization Behavior of Poly(l-lactic acid) Nanocomposites: Nucleation and Growth Probed by Infrared Spectroscopy”, Macromolecules, 2005, 38, 6520 -6527.

Li, Z.; Chen, Z.; Cui, H.; Hales, K.; Qi, K.; Wooley, K.L.; Pochan, D.J. “Disc Morphology and Discto-Cylinder Tunability of Poly(acrylic acid)-b-Poly(methyl acrylate)-b-Polystyrene Triblock Copolymer Solution-State Assemblies, Langmuir, 2005, 21, 7533-7539.

Chen, Z.; Cui, H.; Hales, K.; Li, Z.; Qi, K.; Pochan, D.J.; Wooley, K.L. “Unique Toroidal Morphology from Composition and Sequence Control of Triblock Copolymers,” Journal of the American Chemical Society, 2005, 127, 8592-8593

Kretsinger, J.K.; Haines, L.A.; Ozbas, B.; Pochan, D.J.; Schneider, J.P. “Cytocompatibility of SelfAssembled β-Hairpin Peptide Hydrogel Surfaces,” Biomaterials, 2005, 26, 5177-5186.

Ozbas, B.; Rajagopal, K.; Schneider, J.P.; Pochan, D.J. “Semiflexible Chain Networks Formed via Folding and Self-assembly of b-Hairpin Molecules,” Physical Review Letters, 2004, 93 (26), article no.268106.

Pochan, D.J.; Chen, Z.; Cui, H.; Hales, K.; Qi, K.; Wooley, K.L. “Toroidal Triblock Copolymer Assemblies”, Science, October 1, 2004, 306, 94-97.

Ozbas, B.; Kretsinger, J.; Rajagopal, K.; Schneider, J.P.; Pochan, D.J. “Salt-Triggered Peptide Folding and Consequent Self-Assembly into Hydrogels with Tunable Modulus,” Macromolecules, 2004, 37, 7331-7337.

Krikorian, V.; Pochan, D.J. “Unusual Crystallization Behavior of Organoclay Reinforced Poly (Llactic acid) Nanocomposites,” Macromolecules, 2004, 37, 6480-6491.

Bellomo, E.G.; Wyrsta, M.D.; Pakstis, L.; Pochan, D.J.; Deming, T.J., “Stimuli Responsive Polypeptide Vesicles via Conformation Specific Assembly”, Nature Materials, 2004, 3, 244-248.

Minich, E.A.; Nowak, A.P.; Deming, T.J.; Pochan, D.J. “Rod-rod and Rod-coil Self-Assembly and Phase Behavior of Polypeptide Diblock Copolymers”, Polymer, 2004, 45, 1951-1957.

Pakstis, L.; Nowak, A.P.; Deming, T.J.; Pochan, D.J. “The Effect of Chemistry and Morphology on the Biofunctionality of Self-Assembling Diblock Copolypeptide Hydrogels” Biomacromolecules, 2004, 5, 312-318. 9

Baker, C.; Pradhan, A.; Pakstis, L.; Pochan, D.J.; Shah, S.I. “Synthesis and Antibacterial Properties of Silver Nanoparticles,” Journal of Nanoscience and Nanotechnology, 2004, 5, 1.

Krikorian, V.; Pochan, D.J. “Poly(L-lactic acid)/Layered Silicate Nanocomposite: Fabrication, Characterization and Properties” Chemistry of Materials, 2003, 15, 4317-4324.

Pochan, D.J.; Schneider, J.S.; Kretsinger, J.; Ozbas, B.; Rajagopal, K.; Haines, L. “Thermally Reversible Hydrogels via Intramolecular Folding and Consequent Self-Assembly of a de Novo Designed Peptide” JACS, 2003, 125, 11802-11803.

Schneider, J.P.; Pochan, D.J.; Ozbas, B.; Rajagopal, K.; Pakstis, L.M. ; Gill, J. “Responsive Hydrogels from the Intramolecular Folding and Self-Assembly of a Designed Peptide” JACS, 2002, 124, 15030-15037.

Nowak, A.P.; Breedveld, V.; Pakstis, L.; Pine, D.J.; Pochan, D.J.; Deming, T.J. “Rapid Recovering Hydrogel Scaffolds From Self-Assembling Diblock Copolypeptide Amphiphiles” Nature, 2002, 417, 424 – 428.

Pochan, D.J.; Pakstis, L.; Ozbas, B.; Nowak, A.K.; Deming, T.J. “SANS and cryoTEM Study of Self-Assembled Diblock Copolypeptide Hydrogels with Rich Nano- through Microscale Morphology.” Macromolecules, 2002, 35, 5358-5360.

Krikorian, V.; Nowak, A.P.; Deming, T.J.; Kurian, M.; Galvin, M.E.; Pochan, D.J. “Polypeptidebased Nanocomposite: Structure and Properties of Poly(L-lysine)/Na+-Montmorillonite” J. Polym. Sci., Polym. Phys.,2002, 40, 2579-2586.

Pochan, D.J.; Pakstis, L.; Huang, E.H.; Hawker, C.J.; Vestberg, R.; Pople, J. “Architectural Disparity Effects in the Morphology of Dendrimer-Linear Coil Diblock Copolymers” Macromolecules, 2002, 35(24); 9239-9242.

Yu, M.; Nowak, A.P.; Pochan, D.J.; Deming, T.J. “Methylated Mono- and Diethyleneglycol Functionalized Polylysines: Nonionic, α-Helical, Water Soluble Polypeptides.” JACS, 1999, 121, 12210-12211.