Engineering Commons^™

Recent Approaches In Designing Bioadhesive Materials Inspired By Mussel Adhesive Protein, Pegah Kord Forooshani, Bruce P. Lee

Bruce Lee

Marine mussels secret protein-based adhesives, which enable them to anchor to various surfaces in a saline, intertidal zone. Mussel foot proteins (Mfps) contain a large abundance of a unique, catecholic amino acid, Dopa, in their protein sequences. Catechol offers robust and durable adhe-sion to various substrate surfaces and contributes to the curing of the adhesive plaques. In this article, we review the unique features and the key functionalities of Mfps, catechol chemistry, and strategies for preparing catechol-functionalized poly- mers. Specifically, we reviewed recent findings on the contributions of various features of Mfps on interfacial binding, which include coacervate formation, surface …

Getting To The Root Of Bacterial Hairs: What Is “S”?, Rebecca Gaddis, Samantha O'Conner, Evan Anderson, Terri Camesano, Nancy Burnham

Nancy A. Burnham

An atomic force microscope (AFM) was used to measure the steric forces of lipopolysaccharides (LPS) on the biofilm-forming bacteria, Pseudomonas aeruginosa. It is well known that LPS play a vital role in biofilm formation. These forces were characterized with a modified version of the Alexander and de Gennes (AdG) model for polymers, which is a function of equilibrium brush length, L, probe radius, R, temperature, T, separation distance, D, and an indefinite density variable, s. This last parameter was originally distinguished by de Gennes as the root spacing or mesh spacing depending upon the type of polymer adhesion; however since …

Unraveling The Mystery Of Natural Rubber Biosynthesis. Part Ii: Composition And Growth Of In Vitro Natural Rubber Using High-Resolution Size Exclusion Chromatography, Cheng Ching Chiang, Balaka Barkakaty, Judit Puskas, Wenshuang Xie, Katrina Cornish, Federic Peruch, Alain Deffieux

Balaka Barkakaty

The superior properties of natural rubber (cis-1,4-polyisoprene [NR]) are a function of its structure and composition, properties that still remain a mystery and that are irreplaceable by any synthetic rubber. NR from guayule (Parthenium argentatum) has been gaining special interest for its hypoallergenic properties while maintaining superior mechanical properties that are commonly associated with the Brazilian rubber tree (Hevea brasiliensis), the most common source of NR. Techniques exist to isolate washed rubber particles (WRPs) that contain enzymatically active rubber transferase, to study NR biosynthesis, and previous work on the in vitro NR growth in Hevea has demonstrated the presence of …

Chapter 2 - Thermoplastic-Thermoset Nanostructured Polymer Blends.Pdf, Amos Adeniyi, Oluranti Agboola, Emmanuel R. Sadiku, M. O. Durowoju, P. A. Olubambi, A. B. Reddy, I. D. Ibrahim, W. K. Kupolati

Chongwen Huang

Silver (I)-Imidazole Cyclophane Gem-Diol Complexes Encapsulated By Electrospun Tecophilic Nanofibers: Formation Of Nanosilver Particles And Antimicrobial Activity, Abdulkareem Melaiye, Zhaohui Sun, Khadijah Hindi, Amy Milsted, Daniel Ely, Darrell Reneker, Claire Tessier, Wiley Youngs

Wiley J. Youngs

Silver(I)-imidazole cyclophane gem-diol complex, 3 [Ag2C36 N10(O)4](2+)2(x)-, where x = OH- or CO3(2-), was synthesized and well characterized. The minimum inhibition concentration tests showed that the aqueous form of 3 is 2 times less effective as an antibiotic than 0.5% AgNO3, with about the same amount of silver. The antimicrobial activity of 3 was enhanced when encapsulated into Tecophilic polymer by electrospinning to obtain mats made of nano-fibers. The fiber mats released nanosilver particles, which in turn sustained the antimicrobial activity of the mats over a long period of time. The rate of bactericidal activity of 3 was greatly improved …

Silver (I)-Imidazole Cyclophane Gem-Diol Complexes Encapsulated By Electrospun Tecophilic Nanofibers: Formation Of Nanosilver Particles And Antimicrobial Activity, Abdulkareem Melaiye, Zhaohui Sun, Khadijah Hindi, Amy Milsted, Daniel Ely, Darrell Reneker, Claire Tessier, Wiley Youngs

Claire A. Tessier

Silver(I)-imidazole cyclophane gem-diol complex, 3 [Ag2C36 N10(O)4](2+)2(x)-, where x = OH- or CO3(2-), was synthesized and well characterized. The minimum inhibition concentration tests showed that the aqueous form of 3 is 2 times less effective as an antibiotic than 0.5% AgNO3, with about the same amount of silver. The antimicrobial activity of 3 was enhanced when encapsulated into Tecophilic polymer by electrospinning to obtain mats made of nano-fibers. The fiber mats released nanosilver particles, which in turn sustained the antimicrobial activity of the mats over a long period of time. The rate of bactericidal activity of 3 was greatly improved …

A Ga3+Self-Assembled Fluorescent Probe For Atp Imaging In Vivo, Liangliang Xiao, Shiguo Sun, Zhichao Pei, Yuxin Pei, Yi Pang, Yongqian Xu

Yi Pang

Adenosine 5′-triphosphate (ATP) is a functional molecule associated with many important biological processes. Fluorescent detection methods for ATP with facile performance and high selectivity are in demand. One of the possible multi-membered arrays assembled between DHBO and Ga3+ ions was conducted in aqueous solution, which can selectively recognize ATP with fluorescence enhancement from ADP, AMP and other structurally similar nucleoside triphosphates in vitro and in vivo. ATP facilitates the interaction between DHBO and Ga3+ ions, resulting in the fluorescence increase. The detection limit for ATP was calculated to be 5.49×10−7 M, which is much lower than that of intracellular concentrations …

Synthesis And Electrochemical Properties Of A New Class Of Boron-Containing N-Type Conjugated Polymers, Jianfang Chai, Chao Wang, Li Jia, Yi Pang, Matthew Graham, Stephen Cheng

Yi Pang

Several electron-deficient polymers containing the 9,10-diboroanthracene unit have been synthesized and characterized. Electrochemical study shows that they have high electron affinities. Photoluminescence of rr-P3HT is quenched in the presence of one of the polymers in the solid state, demonstrating the potential utility of this class of polymer as powerful n-type materials in organic photovoltaic devices.

Biocompatible Flavone-Based Fluorogenic Probes For Quick Wash-Free Mitochondria! Imaging In Living Cells, Bin Liu, Mickey Shah, Ge Zhang, Qin Liu, Yi Pang

Yi Pang

Mitochondria, vital organelles existing in almost all eukaryotic cells, play a crucial role in energy metabolism and apoptosis of aerobic organisms. In this work, we report two new flavone-based fluorescent probes, MC-Mito1 and MC-Mito2, for monitoring mitochondria in living cells. These two probes exhibit remarkably low toxicity, good cell permeability, and high specificity; these probes complement the existing library of mitochondrial imaging agents. The new dyes give nearly no background fluorescence, and their application does not require tedious postwashing after cell staining. The appreciable tolerance of MC-Mito2 encourages a broader range of biological applications for understanding the cell degeneration and …

Regioregular Poly(3-Alkanoylthiophene): Synthesis And Electrochemical, Photophysical, Charge Transport, And Photovoltaic Properties, Chao Wang, Felix Kim, Guoqiang Ren, Yongqian Xu, Yi Pang, Samson Jenekhe, Li Jia

Yi Pang

Head-to-tail regioregular poly(3-heptanoylthiophene) (PHOT) was synthesized by Ni-catalyzed polycondensation of the 2,2-dimethyl-1,3-propanediol-protected Grignard monomer followed by deprotection. Cyclic voltammetric (CV) study demonstrates that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of PHOT are 0.5 eV lower in energy than those of the head-to-tail poly(3-hexylthiophene) (HT-P3HT). Their optical band gaps are essentially the same. Incomplete photoluminescence (PL) quenching was observed in thin films of the 1:1 blend of PHOT and HT-P3HT. PHOT displayed a glass transition at ∼269 °C and decomposed at ∼300 °C according to differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Wide-angle X-ray …

Improvement Of Mechanical Properties And Water Stability Of Vegetable Protein Based Plastics, Gowrishankar Srinivasan

Gowrishankar Srinivasan

Bio-renewable bio-degradable plastics are a potential solution to the growing problems of pollution caused by petroleum plastics and dependency on foreign nations for petroleum resources. One possible feed stock for these materials are vegetable proteins, especially from soy bean and corn. These proteins have relatively high molecular weights and have the potential of being processed with standard polymer processing technologies. But some issues that need to be addressed are their water instability (soy protein) and inferior mechanical properties as compared to petroleum derived plastics. In this study, soy protein isolates (SPI) and zein protein was processed with various additives and …

Identification Of A Highly Specific Hydroxyapatite-Binding Peptide Using Phage Display, Marc Roy, Scott Stanley, Eric Amis, Matthew Becker

Eric J. Amis

A peptide sequence SVSVGMKPSPRP that selectively recognizes hydroxyapatite (HA) is identified by using a phage display approach. The engineered sequence exhibits chemical and structural specificity for HA over calcium carbonate and HA's amorphous calcium phosphate precursor. In situ binding to HA in a tooth cross section further demonstrates the sequence specificity and utility in nondestructive imaging applications.

Biocompatible Flavone-Based Fluorogenic Probes For Quick Wash-Free Mitochondria! Imaging In Living Cells, Bin Liu, Mickey Shah, Ge Zhang, Qin Liu, Yi Pang

Ge Zhang

Mitochondria, vital organelles existing in almost all eukaryotic cells, play a crucial role in energy metabolism and apoptosis of aerobic organisms. In this work, we report two new flavone-based fluorescent probes, MC-Mito1 and MC-Mito2, for monitoring mitochondria in living cells. These two probes exhibit remarkably low toxicity, good cell permeability, and high specificity; these probes complement the existing library of mitochondrial imaging agents. The new dyes give nearly no background fluorescence, and their application does not require tedious postwashing after cell staining. The appreciable tolerance of MC-Mito2 encourages a broader range of biological applications for understanding the cell degeneration and …

Bioactive Surface Modification Of Metal Oxides Via Catechol-Bearing Modular Peptides: Multivalent-Binding, Surface Retention, And Peptide Bioactivity, Wen Tang, Gina Policastro, Geng Hua, Kai Guo, Chrys Wesdemiotis, Gary Doll, Matthew Becker

Gary L. Doll

A series of multivalent dendrons containing a bioactive osteogenic growth peptide (OGP) domain and surface-binding catechol domains were obtained through solid phase synthesis, and their binding affinity to hydroxyapatite, TiO2, ZrO2, CeO2, Fe3O4 and gold was characterized using a quartz crystal microbalance with dissipation (QCM-d). Using the distinct difference in binding affinity of the bioconjugate to the metal oxides, TiO2-coated glass slides were selectively patterned with bioactive peptides. Cell culture studies demonstrated the bioavailability of the OGP and that OGP remained on the surface for at least 2 weeks under in vitro cell culture conditions. Bone sialoprotein (BSP) and osteocalcein …

Three-Dimensional Confocal Microscopy Indentation Method For Hydrogel Elasticity Measurement, Donghee Lee, Md Mahmudur Rahman, You Zhou, Sangjin Ryu

Md Mahmudur Rahman

No abstract provided.

Improvement Of Mechanical Properties And Water Stability Of Vegetable Protein Based Plastics, Gowrishankar Srinivasan

Gowrishankar Srinivasan

Bio-renewable bio-degradable plastics are a potential solution to the growing problems of pollution caused by petroleum plastics and dependency on foreign nations for petroleum resources. One possible feed stock for these materials are vegetable proteins, especially from soy bean and corn. These proteins have relatively high molecular weights and have the potential of being processed with standard polymer processing technologies. But some issues that need to be addressed are their water instability (soy protein) and inferior mechanical properties as compared to petroleum derived plastics. In this study, soy protein isolates (SPI) and zein protein was processed with various additives and …

A Label-Free High Throughput Resistive-Pulse Sensor For Simultaneous Differentiation And Measurement Of Multiple Particle-Laden Analytes, Ashish Jagtiani, Rupesh Sawant, Jiang Zhe

Dr. Jiang Zhe

We describe an all-electronic, label-free, resistive-pulse sensor that utilizes multiple microchannels for parallel detection, counting and differentiation of multiple biological particles simultaneously. Four particle solutions, including 20 µm and 40 µm polymethacrylate particles, Juniper Scopulorum (Rocky Mountain Juniper) pollen and Populus deltidoes (Eastern Cottonwood) pollen, were loaded to the four peripheral reservoirs, respectively, and were driven to the central reservoir through four microchannels, all operating simultaneously for particle detection and counting. Experiments demonstrated that this sensor was able to differentiate and count multiple particle solutions simultaneously through its four microchannels fabricated on polymer membranes. Thus the sensing throughput has been …

Synthesis And Characterization Of Sr3Femoo6.88: An Oxygen-Deficient 2d Analogue Of The Double Perobskite Sr2Femoo6, Gabriel Veith, Martha Greenblatt, Mark Croft, K. Ramanujachary, Jason Hattrick-Simpers, Samuel Lofland, Israel Nowik

Jason R. Hattrick-Simpers

No abstract provided.

One-Step Production Of Long-Chain Hydrocarbons From Waste-Biomass-Derived Chemicals Using Bi-Functional Heterogeneous Catalysts, Cun Wen, Elizabeth Barrow, Jason Hattrick-Simpers, Jochen Lauterbach

Jason R. Hattrick-Simpers

n this study, we demonstrate the production of long-chain hydrocarbons (C8+) from 2-methylfuran (2MF) and butanal in a single step reactive process by utilizing a bi-functional catalyst with both acid and metallic sites. Our approach utilizes a solid acid for the hydroalkylation function and as a support as well as a transition metal as hydrodeoxygenation catalyst. A series of solid acids was screened, among which MCM-41 demonstrated the best combination of activity and stability. Platinum nanoparticles were then incorporated into the MCM-41. The Pt/MCM-41 catalyst showed 96% yield for C8+ hydrocarbons and the catalytic performance was stable over four reaction …

Reduction Of Water Surface Tension Significantly Impacts Gecko Adhesion Underwater, Peter Niewiarowski, Ali Dhinojwala, Alyssa Stark, Brandon Mcclung

Dr. Peter H. Niewiarowski

The gecko adhesive system is dependent on weak van der Waals interactions that are multiplied across thousands of fine hair-like structures (setae) on geckos' toe pads. Due to the requirements of van der Waals forces, we expect that any interruption between the setae and substrate, such as a water layer, will compromise adhesion. Our recent results suggest, however, that the air layer (plastron) surrounding the superhydrophobic toe pads aid in expelling water at the contact interface and create strong shear adhesion in water when in contact with hydrophobic surfaces. To test the function of the air plastron, we reduced the …

The Role Of Surface Chemistry In Adhesion And Wetting Of Gecko Toe Pads, Ali Dhinojwala, Peter Niewiarowski, Ila Badge, Alyssa Stark, Eva Paoloni

Dr. Peter H. Niewiarowski

An array of micron-sized setal hairs offers geckos a unique ability to walk on vertical surfaces using van der Waals interactions. Although many studies have focused on the role of surface morphology of the hairs, very little is known about the role of surface chemistry on wetting and adhesion. We expect that both surface chemistry and morphology are important, not only to achieve optimum dry adhesion but also for increased efficiency in self-cleaning of water and adhesion under wet conditions. Here, we used a plasma-based vapor deposition process to coat the hairy patterns on gecko toe pad sheds with polar …

Monte Carlo Simulation Of Tri-Functional Branching And Tetra-Functional Crosslinking In Emulsion Polymerization Of Butadiene, Esmaiel Jabbari

Esmaiel Jabbari

No abstract provided.

Synthesis Of Acrylic Acid Hydrogel By Y-Irradiation Cross-Linking Of Polyacrylic Acid In Aqueous Solution, Esmaiel Jabbari, Samyra Nozari

Esmaiel Jabbari

No abstract provided.

Measurement Of Adhesion And Interfacial Thickness Of Polymer-Polymer Interfaces With Electron Microscopy, Esmaiel Jabbari, Nikolaos Peppas

Esmaiel Jabbari

No abstract provided.

Mapping The Concentration Profile At The Poly(Vinyl Chloride)/Poly(Ethyl Methacrylate) Interface, Esmaiel Jabbari, Nikolaos Peppas

Esmaiel Jabbari

No abstract provided.

Temperature Effects On Interdiffusion At Glassy/Rubbery Interfaces, Esmaiel Jabbari, Nikolaos Peppas

Esmaiel Jabbari

No abstract provided.

Swelling Behavior And Cell Viability Of Dehydrothermally Crosslinked Poly(Vinyl Alcohol) Hydrogel Grafted With N-Vinyl Pyrrolidone Or Acrylic Acid Using Γ-Radiation, Esmaiel Jabbari, Saeed Karbasi

Esmaiel Jabbari

No abstract provided.

Characterization Of Microcapsules Prepared By Interfacial Polycondensation Of Methylene Bis(Phenyl Isocyanate) With Hexamethylene Diamine, Esmaiel Jabbari

Esmaiel Jabbari

No abstract provided.

A Model For Interdiffusion At Interfaces Of Polymers With Dissimilar Physical Properties, Esmaiel Jabbari, Nikolaos Peppas

Esmaiel Jabbari

No abstract provided.

Quantitative Measurement Of Interdiffusion At Polymer–Polymer Interfaces With Tem/Eds And Eels, Esmaiel Jabbari, Nikolaos Peppas

Esmaiel Jabbari

No abstract provided.