Bioinspired Design of Dynamic Materials

An emerging approach for design of dynamic materials involves mimicking natural systems, which are adept at changing their structure and function in response to their environment. Biological systems possess a diverse range of dynamic mechanisms, including competitive ligand―protein binding, enzyme-catalyzed remodeling, and allosteric protein conformational changes. These dynamic mechanisms are now being exploited by materials scientists and engineers to design "bioinspired" synthetic materials that undergo responsive assembly and disassembly as well as dynamic volume and shape changes. The purpose of this review is to describe recent progress in design and development of bioinspired dynamic materials, with a particular emphasis on hydrogel networks. We specifically focus on emerging approaches that use biological phenomena as an inspiration for design of materials.

[1]  Shelly R Peyton,et al.  The effects of matrix stiffness and RhoA on the phenotypic plasticity of smooth muscle cells in a 3-D biosynthetic hydrogel system. , 2008, Biomaterials.

[2]  Jennifer E. Padilla,et al.  Designing supramolecular protein assemblies. , 2002, Current opinion in structural biology.

[3]  T. Miyata,et al.  Preparation of poly(2-glucosyloxyethyl methacrylate)-concanavalin A complex hydrogel and its glucose-sensitivity , 1996 .

[4]  R. Eisenthal,et al.  A smart membrane based on an antigen‐responsive hydrogel , 2007, Biotechnology and bioengineering.

[5]  Jongseong Kim,et al.  Label-free biosensing with hydrogel microlenses. , 2006, Angewandte Chemie.

[6]  D. Urry Elastic molecular machines in metabolism and soft-tissue restoration. , 1999, Trends in biotechnology.

[7]  D. Seliktar,et al.  Biosynthetic hydrogel scaffolds made from fibrinogen and polyethylene glycol for 3D cell cultures. , 2005, Biomaterials.

[8]  A S Hoffman,et al.  Formation of poly(glucosyloxyethyl methacrylate)-concanavalin A complex and its glucose-sensitivity. , 1994, Journal of biomaterials science. Polymer edition.

[9]  J. Mano Stimuli‐Responsive Polymeric Systems for Biomedical Applications , 2008 .

[10]  Ralph Müller,et al.  Synthetic extracellular matrices for in situ tissue engineering , 2004, Biotechnology and bioengineering.

[11]  Mansoor M. Amiji,et al.  Preparation and Characterization of Freeze-dried Chitosan-Poly(Ethylene Oxide) Hydrogels for Site-Specific Antibiotic Delivery in the Stomach , 1996, Pharmaceutical Research.

[12]  Rein V. Ulijn,et al.  Peptide-based stimuli-responsive biomaterials. , 2006, Soft matter.

[13]  D. Tirrell,et al.  Engineering the extracellular matrix: a novel approach to polymeric biomaterials. I. Control of the physical properties of artificial protein matrices designed to support adhesion of vascular endothelial cells. , 2000, Biomacromolecules.

[14]  Aaron D Baldwin,et al.  Production of heparin-functionalized hydrogels for the development of responsive and controlled growth factor delivery systems. , 2007, Journal of controlled release : official journal of the Controlled Release Society.

[15]  Dustin J. Maxwell,et al.  Development of rationally designed affinity-based drug delivery systems. , 2005, Acta biomaterialia.

[16]  L. Bachas,et al.  Chemically Tunable Lensing of Stimuli‐Responsive Hydrogel Microdomes , 2007 .

[17]  Amos Bairoch,et al.  The ENZYME database in 2000 , 2000, Nucleic Acids Res..

[18]  A. Metters,et al.  Synthetic matrix metalloproteinase-sensitive hydrogels for the conduction of tissue regeneration: Engineering cell-invasion characteristics , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[19]  Lisa Pakstis,et al.  Responsive hydrogels from the intramolecular folding and self-assembly of a designed peptide. , 2002, Journal of the American Chemical Society.

[20]  S. Sakiyama-Elbert,et al.  Release rate controls biological activity of nerve growth factor released from fibrin matrices containing affinity-based delivery systems. , 2008, Journal of biomedical materials research. Part A.

[21]  S. Asher,et al.  Fast responsive crystalline colloidal array photonic crystal glucose sensors. , 2006, Analytical chemistry.

[22]  Dan W. Urry,et al.  Molecular Machines: How Motion and Other Functions of Living Organisms Can Result from Reversible Chemical Changes , 1993 .

[23]  J. Hubbell,et al.  Molecularly engineered PEG hydrogels: a novel model system for proteolytically mediated cell migration. , 2005, Biophysical journal.

[24]  Sang Hoon Lee,et al.  Electrical response characterization of chitosan/polyacrylonitrile hydrogel in NaCl solutions , 2003 .

[25]  J. V. Hest,et al.  Protein-based materials, toward a new level of structural control. , 2001, Chemical communications.

[26]  Franz E Weber,et al.  Bone repair with a form of BMP-2 engineered for incorporation into fibrin cell ingrowth matrices. , 2005, Biotechnology and bioengineering.

[27]  A. Metters,et al.  Metal-chelating affinity hydrogels for sustained protein release. , 2007, Journal of biomedical materials research. Part A.

[28]  J. A. Hubbell,et al.  Cell‐Responsive Synthetic Hydrogels , 2003 .

[29]  J. Hubbell,et al.  Covalently conjugated VEGF--fibrin matrices for endothelialization. , 2001, Journal of controlled release : official journal of the Controlled Release Society.

[30]  J. Hubbell,et al.  The role of actively released fibrin-conjugated VEGF for VEGF receptor 2 gene activation and the enhancement of angiogenesis. , 2008, Biomaterials.

[31]  Anna Gutowska,et al.  Lessons from nature: stimuli-responsive polymers and their biomedical applications. , 2002, Trends in biotechnology.

[32]  R. Ulijn,et al.  Exploiting enzymatic (reversed) hydrolysis in directed self-assembly of peptide nanostructures. , 2008, Small.

[33]  Neetu Singh,et al.  Influence of ancillary binding and nonspecific adsorption on bioresponsive hydrogel microlenses. , 2007, Biomacromolecules.

[34]  K. Healy,et al.  Thermo-responsive peptide-modified hydrogels for tissue regeneration. , 2001, Biomacromolecules.

[35]  J. Hubbell,et al.  Controlled release of nerve growth factor from a heparin-containing fibrin-based cell ingrowth matrix. , 2000, Journal of controlled release : official journal of the Controlled Release Society.

[36]  N A Peppas,et al.  Glucose-sensitivity of glucose oxidase-containing cationic copolymer hydrogels having poly(ethylene glycol) grafts. , 2000, Journal of Controlled Release.

[37]  A. Metters,et al.  Enhanced Protein Delivery from Photopolymerized Hydrogels Using a Pseudospecific Metal Chelating Ligand , 2006, Pharmaceutical Research.

[38]  Takashi Miyata,et al.  A reversibly antigen-responsive hydrogel , 1999, Nature.

[39]  M. Madou,et al.  Genetically engineered protein in hydrogels tailors stimuli-responsive characteristics , 2005, Nature Materials.

[40]  T. M. Parker,et al.  Human amniotic cell sheet harvest using a novel temperature-responsive culture surface coated with protein-based polymer. , 2006, Tissue engineering.

[41]  R. Eisenthal,et al.  A reversible hydrogel membrane for controlling the delivery of macromolecules. , 2003, Biotechnology and bioengineering.

[42]  Jyh-Ping Chen,et al.  Thermo-responsive chitosan-graft-poly(N-isopropylacrylamide) injectable hydrogel for cultivation of chondrocytes and meniscus cells. , 2006, Macromolecular bioscience.

[43]  R. Eisenthal,et al.  NAD‐sensitive hydrogel for the release of macromolecules , 2004, Biotechnology and bioengineering.

[44]  D. Wirtz,et al.  Reversible hydrogels from self-assembling artificial proteins. , 1998, Science.

[45]  J. Jansen,et al.  PLGA microsphere/calcium phosphate cement composites for tissue engineering: in vitro release and degradation characteristics , 2008, Journal of biomaterials science. Polymer edition.

[46]  Matthias P Lutolf,et al.  Biomolecular hydrogels formed and degraded via site-specific enzymatic reactions. , 2007, Biomacromolecules.

[47]  W. Murphy,et al.  Controllable Soluble Protein Concentration Gradients in Hydrogel Networks , 2008, Advanced functional materials.

[48]  C. Dobson,et al.  Formation of mixed fibrils demonstrates the generic nature and potential utility of amyloid nanostructures , 2000 .

[49]  V. Ravaine,et al.  Monodispersed glucose-responsive microgels operating at physiological salinity. , 2006, Biomacromolecules.

[50]  E. Atkins,et al.  Chemical sequence control of beta-sheet assembly in macromolecular crystals of periodic polypeptides. , 1994, Science.

[51]  L. Griffith,et al.  Control and Prediction of Gelation Kinetics in Enzymatically Cross-Linked Poly(ethylene glycol) Hydrogels , 2000 .

[52]  Jindrich Kopecek,et al.  Peptide-directed self-assembly of hydrogels. , 2009, Acta biomaterialia.

[53]  A G Mikos,et al.  Controlled release of rhBMP-2 loaded poly(dl-lactic-co-glycolic acid)/calcium phosphate cement composites in vivo. , 2005, Journal of controlled release : official journal of the Controlled Release Society.

[54]  Ashutosh Chilkoti,et al.  Synthesis and in vitro evaluation of enzymatically cross-linked elastin-like polypeptide gels for cartilaginous tissue repair. , 2005, Tissue engineering.

[55]  I. Hamachi,et al.  Photo-responsive gel droplet as a nano- or pico-litre container comprising a supramolecular hydrogel. , 2008, Chemical communications.

[56]  M. Hunkapiller,et al.  Purification of bovine bone morphogenetic protein by hydroxyapatite chromatography. , 1984, Proceedings of the National Academy of Sciences of the United States of America.

[57]  R. Ulijn,et al.  Enzyme-responsive hydrogel particles for the controlled release of proteins: designing peptide actuators to match payload. , 2008, Soft matter.

[58]  D. Seliktar,et al.  Compositional alterations of fibrin-based materials for regulating in vitro neural outgrowth. , 2008, Tissue engineering. Part A.

[59]  P. Messersmith,et al.  In situ crosslinking of a biomimetic peptide-PEG hydrogel via thermally triggered activation of factor XIII. , 2002, Biomaterials.

[60]  S. Sakiyama-Elbert,et al.  Effect of controlled delivery of neurotrophin-3 from fibrin on spinal cord injury in a long term model. , 2006, Journal of controlled release : official journal of the Controlled Release Society.

[61]  Ian M. Donaldson,et al.  The Biomolecular Interaction Network Database and related tools 2005 update , 2004, Nucleic Acids Res..

[62]  Y Bruce Yu,et al.  Coiled-coils: stability, specificity, and drug delivery potential. , 2002, Advanced drug delivery reviews.

[63]  A. Pandit,et al.  Characterization of a microbial transglutaminase cross-linked type II collagen scaffold. , 2006, Tissue engineering.

[64]  Igor K Lednev,et al.  High ionic strength glucose-sensing photonic crystal. , 2003, Analytical chemistry.

[65]  M. Fussenegger,et al.  Drug-sensing hydrogels for the inducible release of biopharmaceuticals. , 2008, Nature materials.

[66]  Rein V Ulijn,et al.  Enzyme-triggered self-assembly of peptide hydrogels via reversed hydrolysis. , 2006, Journal of the American Chemical Society.

[67]  Chunyu Xu,et al.  Refolding hydrogels self-assembled from N-(2-hydroxypropyl)methacrylamide graft copolymers by antiparallel coiled-coil formation. , 2006, Biomacromolecules.

[68]  B. Catargi,et al.  Glucose-responsive microgels with a core-shell structure. , 2008, Journal of Colloid and Interface Science.

[69]  K. Healy,et al.  Synthesis and characterization of injectable poly(N-isopropylacrylamide-co-acrylic acid) hydrogels with proteolytically degradable cross-links. , 2003, Biomacromolecules.

[70]  M. Brenner,et al.  Controlled release of nerve growth factor enhances sciatic nerve regeneration , 2003, Experimental Neurology.

[71]  Françoise M. Winnik,et al.  Volumetric studies of aqueous polymer solutions using pressure perturbation calorimetry: A new look at the temperature-induced phase transition of poly(N-isopropylacrylamide) in water and D2O , 2001 .

[72]  S. Asher,et al.  Photonic crystal glucose-sensing material for noninvasive monitoring of glucose in tear fluid. , 2004, Clinical chemistry.

[73]  W. Murphy,et al.  Protein‐Based Hydrogels with Tunable Dynamic Responses , 2008 .

[74]  T. Okano,et al.  Effects of cross-linked structure on temperature-responsive hydrophobic interaction of poly(N-isopropylacrylamide) hydrogel-modified surfaces with steroids , 1999 .

[75]  T. Okano,et al.  Copolymerization of 2-carboxyisopropylacrylamide with N-isopropylacrylamide accelerates cell detachment from grafted surfaces by reducing temperature. , 2003, Biomacromolecules.

[76]  Ralph Müller,et al.  Recombinant protein-co-PEG networks as cell-adhesive and proteolytically degradable hydrogel matrixes. Part II: biofunctional characteristics. , 2006, Biomacromolecules.

[77]  G. McConnell,et al.  Enzyme responsive polymer hydrogel beads. , 2005, Chemical communications.

[78]  Matthew J. Silva,et al.  PDGF‐BB released in tendon repair using a novel delivery system promotes cell proliferation and collagen remodeling , 2007, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[79]  R Langer,et al.  Controlled and modulated release of basic fibroblast growth factor. , 1991, Biomaterials.

[80]  P. Messersmith,et al.  Rational design of transglutaminase substrate peptides for rapid enzymatic formation of hydrogels. , 2003, Journal of the American Chemical Society.

[81]  P. Messersmith,et al.  Formation of fibrinogen-based hydrogels using phototriggerable diplasmalogen liposomes. , 2002, Bioconjugate chemistry.

[82]  J. Hubbell,et al.  Recombinant protein-co-PEG networks as cell-adhesive and proteolytically degradable hydrogel matrixes. Part I: Development and physicochemical characteristics. , 2005, Biomacromolecules.

[83]  H. Bianco-Peled,et al.  The effect of structural alterations of PEG-fibrinogen hydrogel scaffolds on 3-D cellular morphology and cellular migration. , 2006, Biomaterials.

[84]  Isao Shinohara,et al.  Glucose Induced Permeation Control of Insulin through a Complex Membrane Consisting of Immobilized Glucose Oxidase and a Poly(amine) , 1984 .

[85]  D. Urry Physical Chemistry of Biological Free Energy Transduction As Demonstrated by Elastic Protein-Based Polymers† , 1997 .

[86]  T. Miyata,et al.  Biomolecule-sensitive hydrogels. , 2002, Advanced drug delivery reviews.

[87]  L. Poole,et al.  Hydroxyapatite chromatography: altering the phosphate-dependent elution profile of protein as a function of pH. , 2003, Analytical biochemistry.

[88]  Thiennu H. Vu,et al.  Matrix metalloproteinases: effectors of development and normal physiology. , 2000, Genes & development.

[89]  D. Eisenberg,et al.  Design of three-dimensional domain-swapped dimers and fibrous oligomers. , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[90]  Jongseong Kim,et al.  Bioresponsive hydrogel microlenses. , 2005, Journal of the American Chemical Society.

[91]  Rein V. Ulijn,et al.  Enzyme‐Responsive Polymer Hydrogel Particles for Controlled Release , 2007 .

[92]  M. Hecht,et al.  De novo amyloid proteins from designed combinatorial libraries. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[93]  D Seliktar,et al.  MMP-2 sensitive, VEGF-bearing bioactive hydrogels for promotion of vascular healing. , 2004, Journal of biomedical materials research. Part A.

[94]  C. Alexander,et al.  Stimuli responsive polymers for biomedical applications. , 2005, Chemical Society reviews.

[95]  S. Sakai,et al.  Synthesis and characterization of both ionically and enzymatically cross-linkable alginate. , 2007, Acta biomaterialia.

[96]  B. Ratner,et al.  Glucose-sensitive membrane coated porous filters for control of hydraulic permeability and insulin delivery from a pressurized reservoir , 1995 .

[97]  M. K. McDermott,et al.  Mechanical properties of biomimetic tissue adhesive based on the microbial transglutaminase-catalyzed crosslinking of gelatin. , 2004, Biomacromolecules.

[98]  Dustin J. Maxwell,et al.  Rationally designed peptides for controlled release of nerve growth factor from fibrin matrices. , 2007, Journal of biomedical materials research. Part A.

[99]  N. Peppas,et al.  Relaxational behavior and swelling‐pH master curves of poly[(diethylaminoethyl methacrylate)‐graft‐(ethylene glycol)] hydrogels , 2005 .

[100]  J. Hubbell,et al.  Development of growth factor fusion proteins for cell‐triggered drug delivery , 2001, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[101]  M. Nugent,et al.  pH Regulates Vascular Endothelial Growth Factor Binding to Fibronectin , 2004, Journal of Biological Chemistry.

[102]  A. George,et al.  Phosphorylated proteins and control over apatite nucleation, crystal growth, and inhibition. , 2008, Chemical reviews.

[103]  Y. Takaguchi,et al.  A photo-responsive hydrogelator having gluconamides at its peripheral branches. , 2008, Organic & biomolecular chemistry.

[104]  Kristi L Kiick,et al.  Manipulation of hydrogel assembly and growth factor delivery via the use of peptide-polysaccharide interactions. , 2006, Journal of controlled release : official journal of the Controlled Release Society.

[105]  E. Furst,et al.  Growth factor mediated assembly of cell receptor-responsive hydrogels. , 2007, Journal of the American Chemical Society.

[106]  Russell J. Stewart,et al.  Hybrid hydrogels assembled from synthetic polymers and coiled-coil protein domains , 1999, Nature.

[107]  M. Nugent,et al.  Regulation of Vascular Endothelial Growth Factor Binding and Activity by Extracellular pH* , 2003, Journal of Biological Chemistry.

[108]  J. Hubbell,et al.  Development of fibrin derivatives for controlled release of heparin-binding growth factors. , 2000, Journal of controlled release : official journal of the Controlled Release Society.

[109]  A. Pandit,et al.  Assessment of cell viability in a three-dimensional enzymatically cross-linked collagen scaffold , 2007, Journal of materials science. Materials in medicine.

[110]  Smart hydrogels containing adenylate kinase: translating substrate recognition into macroscopic motion. , 2008, Journal of the American Chemical Society.

[111]  K. Healy,et al.  Synthetic MMP-13 degradable ECMs based on poly(N-isopropylacrylamide-co-acrylic acid) semi-interpenetrating polymer networks. I. Degradation and cell migration. , 2005, Journal of biomedical materials research. Part A.

[112]  Zhiyuan Zhong,et al.  Enzyme-mediated fast in situ formation of hydrogels from dextran-tyramine conjugates. , 2007, Biomaterials.

[113]  K. Healy,et al.  The effect of enzymatically degradable IPN coatings on peri-implant bone formation and implant fixation. , 2007, Journal of biomedical materials research. Part A.

[114]  M. Gerstein,et al.  The morph server: a standardized system for analyzing and visualizing macromolecular motions in a database framework. , 2000, Nucleic acids research.

[115]  Christoph Kayser,et al.  Smectic ordering in solutions and films of a rod-like polymer owing to monodispersity of chain length , 1997, Nature.

[116]  A. Lesk,et al.  Structural mechanisms for domain movements in proteins. , 1994, Biochemistry.

[117]  Electrically controlled release of macromolecules from cross-linked hyaluronic acid hydrogels , 1995 .

[118]  D. Seliktar,et al.  A novel poly(ethylene glycol)-fibrinogen hydrogel for tibial segmental defect repair in a rat model. , 2007, Journal of biomedical materials research. Part A.

[119]  T. Miyata,et al.  Preparation of an Antigen-Sensitive Hydrogel Using Antigen-Antibody Bindings , 1999 .

[120]  Rein V Ulijn,et al.  Enzyme-assisted self-assembly under thermodynamic control. , 2009, Nature nanotechnology.

[121]  K. Healy,et al.  Biomimetic artificial ECMs stimulate bone regeneration. , 2006, Journal of biomedical materials research. Part A.

[122]  Rein V. Ulijn,et al.  Enzyme-responsive materials: a new class of smart biomaterials , 2006 .

[123]  C. Cho,et al.  Drug release from pH-sensitive interpenetrating polymer networks hydrogel based on poly (ethylene glycol) macromer and poly (acrylic acid) prepared by UV cured method , 1996 .

[124]  K. De Yao,et al.  A rapid temperature-responsive sol-gel reversible poly(N-isopropylacrylamide)-g-methylcellulose copolymer hydrogel. , 2004, Biomaterials.

[125]  T. Kusunose,et al.  Hydroxyapatite particles as a controlled release carrier of protein. , 2004, Biomaterials.

[126]  Francis J. Doyle,et al.  Preparation and dynamic response of cationic copolymer hydrogels containing glucose oxidase , 2000 .

[127]  Polymer synthesis: For the living there is hope , 1997, Nature.

[128]  T. Okano,et al.  The effect of extensible PEG tethers on shielding between grafted thermo-responsive polymer chains and integrin-RGD binding. , 2008, Biomaterials.

[129]  Takashi Miyata,et al.  Tumor marker-responsive behavior of gels prepared by biomolecular imprinting , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[130]  Martin Ehrbar,et al.  Cell‐demanded release of VEGF from synthetic, biointeractive cell‐ingrowth matrices for vascularized tissue growth , 2003, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[131]  E. Rosenzweig,et al.  Delivery of neurotrophin-3 from fibrin enhances neuronal fiber sprouting after spinal cord injury. , 2006, Journal of controlled release : official journal of the Controlled Release Society.

[132]  Takashi Miyata,et al.  Preparation of reversibly glucose-responsive hydrogels by covalent immobilization of lectin in polymer networks having pendant glucose , 2004, Journal of biomaterials science. Polymer edition.

[133]  J. R. Long,et al.  Molecular recognition at the protein-hydroxyapatite interface. , 2003, Critical reviews in oral biology and medicine : an official publication of the American Association of Oral Biologists.

[134]  T. M. Parker,et al.  Prevention of Postlaminectomy Epidural Fibrosis Using Bioelastic Materials , 2003, Spine.

[135]  W. J. King,et al.  Dynamic Materials Based on a Protein Conformational Change , 2007 .

[136]  Matthew J. Silva,et al.  The early effects of sustained platelet-derived growth factor administration on the functional and structural properties of repaired intrasynovial flexor tendons: an in vivo biomechanic study at 3 weeks in canines. , 2007, The Journal of hand surgery.

[137]  Francis J. Doyle,et al.  Dynamic Behavior of Glucose-Responsive Poly(methacrylic acid-g-ethylene glycol) Hydrogels , 1997 .

[138]  H. Bianco-Peled,et al.  Defining the role of matrix compliance and proteolysis in three-dimensional cell spreading and remodeling. , 2008, Biophysical journal.

[139]  N A Peppas,et al.  Dynamic behavior of glucose oxidase-containing microparticles of poly(ethylene glycol)-grafted cationic hydrogels in an environment of changing pH. , 2000, Biomaterials.

[140]  Kouichi Sutani,et al.  Intelligent type controlled release systems by radiation techniques , 1999 .

[141]  Neetu Singh,et al.  Displacement-Induced Switching Rates of Bioresponsive Hydrogel Microlenses , 2007 .

[142]  Derek N. Woolfson,et al.  Sticky-end assembly of a designed peptide fiber provides insight into protein fibrillogenesis. , 2000 .

[143]  D. Seliktar,et al.  Matrix stiffness affects spontaneous contraction of cardiomyocytes cultured within a PEGylated fibrinogen biomaterial. , 2007, Acta biomaterialia.

[144]  P. Messersmith,et al.  Enzymatically cross-linked hydrogels and their adhesive strength to biosurfaces. , 2005, Orthodontics & craniofacial research.

[145]  J. Mcdonald,et al.  Controlled release of neurotrophin-3 from fibrin gels for spinal cord injury. , 2004, Journal of controlled release : official journal of the Controlled Release Society.

[146]  D. Kaplan,et al.  PEROXIDASE-CATALYZED CROSSlINKING OF FUNCTIONALIZED POLYASPARTIC ACID POLYMERS , 2002 .

[147]  M. Hecht,et al.  De novo design of beta-sheet proteins. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[148]  Seon Jeong Kim,et al.  Electromechanical properties of hydrogels based on chitosan and poly(hydroxyethyl methacrylate) in NaCl solution , 2004 .

[149]  L. Griffith,et al.  Synthesis and Characterization of Enzymatically-Cross-Linked Poly(ethylene glycol) Hydrogels , 1997 .

[150]  Yi Yan Yang,et al.  Injectable biodegradable hydrogels composed of hyaluronic acid-tyramine conjugates for drug delivery and tissue engineering. , 2005, Chemical communications.

[151]  Kinam Park,et al.  Environment-sensitive hydrogels for drug delivery , 2001 .

[152]  M. Mrksich,et al.  Dynamic hydrogels: translating a protein conformational change into macroscopic motion. , 2007, Angewandte Chemie.

[153]  C. Lowe,et al.  Nanobiotechnology: the fabrication and applications of chemical and biological nanostructures. , 2000, Current opinion in structural biology.

[154]  L. Schmidt‐Mende,et al.  ZnO - nanostructures, defects, and devices , 2007 .

[155]  J. Hubbell,et al.  Glucose sensitivity through oxidation responsiveness. An example of cascade-responsive nano-sensors , 2005 .

[156]  Yalin Tang,et al.  A Temperature-Responsive Copolymer Hydrogel in Controlled Drug Delivery , 2006 .

[157]  D. Pochan,et al.  Thermally reversible hydrogels via intramolecular folding and consequent self-assembly of a de novo designed peptide. , 2003, Journal of the American Chemical Society.

[158]  Steven H. Goods,et al.  Direct Measurement of Extension and Force in Conductive Polymer Gel Actuators , 2001 .

[159]  Bogdan Catargi,et al.  Chemically controlled closed-loop insulin delivery. , 2008, Journal of controlled release : official journal of the Controlled Release Society.

[160]  Y. Aramaki,et al.  Drug release from pH-response polyvinylacetal diethylaminoacetate hydrogel, and application to nasal delivery , 1998 .

[161]  J. Kopeček,et al.  Genetically Engineered Block Copolymers: Influence of the Length and Structure of the Coiled-Coil Blocks on Hydrogel Self-Assembly , 2008, Pharmaceutical Research.

[162]  Jennifer E. Padilla,et al.  Nanohedra: Using symmetry to design self assembling protein cages, layers, crystals, and filaments , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[163]  N. Peppas,et al.  Preparation of poly(methacrylic acid-g-poly(ethylene glycol)) nanospheres from methacrylic monomers for pharmaceutical applications. , 2002, International journal of pharmaceutics.

[164]  Mark Gerstein,et al.  Normal modes for predicting protein motions: A comprehensive database assessment and associated Web tool , 2005, Protein science : a publication of the Protein Society.

[165]  Jeffrey A. Hubbell,et al.  Cell-Demanded Liberation of VEGF121 From Fibrin Implants Induces Local and Controlled Blood Vessel Growth , 2004, Circulation research.