Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Institution
- Publication
- Publication Type
- File Type
Articles 1 - 17 of 17
Full-Text Articles in Engineering
Impact Of Secondary Reactive Species On The Apparent Decoupling Of Poly(Ethylene Glycol) Diacrylate Hydrogel Average Mesh Size And Modulus, Dany J. Munoz Pinto, S. Samavedi, B. Grigoryan, M. S. Hahn
Impact Of Secondary Reactive Species On The Apparent Decoupling Of Poly(Ethylene Glycol) Diacrylate Hydrogel Average Mesh Size And Modulus, Dany J. Munoz Pinto, S. Samavedi, B. Grigoryan, M. S. Hahn
Engineering Faculty Research
Poly(ethylene glycol) diacrylate (PEGDA) hydrogels are widely used in biotechnology due to their in situ crosslinking capacity and tunable physical properties. However, as with all single component hydrogels, the modulus of PEGDA networks cannot be tailored independently of mesh size. This interdependence places significant limitations on their use for defined, 3D cell-microenvironment studies and for certain controlled release applications. The incorporation of secondary reactive species (SRS) into PEGDA hydrogels has previously been shown to allow the identification of up to 6 PEGDA hydrogel formulations for which distinct moduli can be obtained at consistent average mesh size (or vice versa). However, …
Carboxymethylcellulose Hydrogels Support Cns-Derived Tumor Cell Chemotactic Migration, Tanya Singh, Chandrasekhar Kothapalli, Devika Verma, Steven Nicoll, Maribel Vazquez
Carboxymethylcellulose Hydrogels Support Cns-Derived Tumor Cell Chemotactic Migration, Tanya Singh, Chandrasekhar Kothapalli, Devika Verma, Steven Nicoll, Maribel Vazquez
Publications and Research
The local microenvironment plays an important role in maintaining the dynamics of the extracellular matrix (ECM) and the cell-ECM relationship. ECM is a complex network of molecules with distinct mechanical and biochemical characteristics. When the mechanisms that are in place to maintain ECM homeostasis are deregulated, most likely, this is the onset of cancer. The ECM becomes highly disorganized and the cell-matrix relationship changes, thus promoting alternations in cell mechanisms and metastasis. Medulloblastoma (MB) is one of the most common, malignant pediatric brain tumors in the United States. In order to gain a better understanding between the cell-ECM relationship and …
Synthesis Of Clickable Poly(Ethylene Glycol) Derivatives For Fabrication Of Modular Microsphere-Based Scaffolds To Promote Vascularization, Peter Nguyen
McKelvey School of Engineering Theses & Dissertations
Vascularization plays an important role in supporting transplanted tissues and cells in tissue engineering applications. Most tissues require access to blood vessels for the delivery of oxygen and nutrients, as well as the removal of carbon dioxide and cellular waste products. Without an adequate blood supply, cells within tissue-engineered constructs and scaffolds lose viability and fail to perform their intended functions. The goal of this dissertation was to design scaffolds that can promote vascularization of biomaterial implants for biomedical applications. In order to accomplish this goal, clickable poly(ethylene glycol) (PEG) derivatives were synthesized in order to fabricate modular microsphere-based scaffolds …
Printed Ionic-Covalent Entanglement Hydrogels From Carrageenan And An Epoxy Amine, Shannon Bakarich, Paul Balding, Robert Gorkin Iii, Geoffrey Spinks, Marc In Het Panhuis
Printed Ionic-Covalent Entanglement Hydrogels From Carrageenan And An Epoxy Amine, Shannon Bakarich, Paul Balding, Robert Gorkin Iii, Geoffrey Spinks, Marc In Het Panhuis
Robert Gorkin III
Carrageenan/epoxy amine ionic-covalent entanglement hydrogels were fabricated on a 3D printer. The thermal gel transition behaviour of the biopolymer kappa-carrageenan was exploited to fix the shape of the patterned ink until a covalent polymer network formed by epoxy amine addition chemistry. The printed hydrogels display a work of extension value of 1.4 ± 0.3 MJ m-3.
Crosslinked Hyaluronic Acid Hydrogel Networks Designed As Mechanical Actuators, Pushkar S. Varde
Crosslinked Hyaluronic Acid Hydrogel Networks Designed As Mechanical Actuators, Pushkar S. Varde
Dissertations - ALL
Bioengineers are in constant pursuit of solutions to problems facing the medical and pharmaceutical field by designing biomaterials that closely mimic the target natural systems. A unique collection of polymers, known as polymeric actuators, have been devised with the ability to convert an external stimulus to a change in shape, size or permeability. The current options within polymeric biomaterials with multi-functionality include matrices that are biocompatible, biodegradable, quick transitioning / shape changing, and mechanically tunable. These properties have been harnessed for application such as stents, valves, semi permeable membranes, and dynamic cell culture substrates. For such applications quick and uniform …
Characterization Of Sequential Collagen-Poly(Ethylene Glycol) Diacrylate Interpenetrating Networks And Initial Assessment Of Their Potential For Vascular Tissue Engineering, Dany J. Munoz Pinto, Andrea C. Jimenez-Vergara, T. P. Gharat, M. S. Hahn
Characterization Of Sequential Collagen-Poly(Ethylene Glycol) Diacrylate Interpenetrating Networks And Initial Assessment Of Their Potential For Vascular Tissue Engineering, Dany J. Munoz Pinto, Andrea C. Jimenez-Vergara, T. P. Gharat, M. S. Hahn
Engineering Faculty Research
Collagen hydrogels have been widely investigated as scaffolds for vascular tissue engineering due in part to the capacity of collagen to promote robust cell adhesion and elongation. However, collagen hydrogels display relatively low stiffness and strength, are thrombogenic, and are highly susceptible to cell-mediated contraction. In the current work, we develop and characterize a sequentially-formed interpenetrating network (IPN) that retains the benefits of collagen, but which displays enhanced mechanical stiffness and strength, improved thromboresistance, high physical stability and resistance to contraction. In this strategy, we first form a collagen hydrogel, infuse this hydrogel with poly(ethylene glycol) diacrylate (PEGDA), and subsequently …
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
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.
Viscoelastic Characterization And Modeling Of Gelation Kinetics Of Injectable In Situ Cross-Linkable Poly(Lactide-Co-Ethylene Oxide-Co-Fumarate) Hydrogels, Alireza Sarvestani, Xuezhong He, Esmaiel Jabbari
Viscoelastic Characterization And Modeling Of Gelation Kinetics Of Injectable In Situ Cross-Linkable Poly(Lactide-Co-Ethylene Oxide-Co-Fumarate) Hydrogels, Alireza Sarvestani, Xuezhong He, Esmaiel Jabbari
Esmaiel Jabbari
No abstract provided.
Swelling Behavior Of Acrylic Acid Hydrogels Prepared By Γ-Radiation Crosslinking Of Polyacrylic Acid In Aqueous Solution, Esmaiel Jabbari, Samyra Nozari
Swelling Behavior Of Acrylic Acid Hydrogels Prepared By Γ-Radiation Crosslinking Of Polyacrylic Acid In Aqueous Solution, Esmaiel Jabbari, Samyra Nozari
Esmaiel Jabbari
No abstract provided.
Effect Of Tensile Load On The Actuation Performance Of Ph-Sensitive Hydrogels, Sina Naficy, Geoffrey M. Spinks
Effect Of Tensile Load On The Actuation Performance Of Ph-Sensitive Hydrogels, Sina Naficy, Geoffrey M. Spinks
Australian Institute for Innovative Materials - Papers
pH-responsive hydrogels are capable of converting chemical energy to mechanical work. To optimize their use as actuators, their response when operating against an external load must be fully characterized. Here, the actuation strain of a model pH-sensitive hydrogel as a function of different constant loads is studied. The experimental actuation strain, produced by switching the pH from 2 to 12, decreases significantly and monotonically with increasing initial tensile load. Two models are developed to predict the actuation strain as a function of applied stress. Simple mechanical models based on the change in hydrogel modulus and cross sectional area due to …
Time-Dependent Mechanical Properties Of Tough Ionic-Covalent Hybrid Hydrogels, Hai Xin, Hugh Ralph Brown, Sina Naficy, Geoffrey M. Spinks
Time-Dependent Mechanical Properties Of Tough Ionic-Covalent Hybrid Hydrogels, Hai Xin, Hugh Ralph Brown, Sina Naficy, Geoffrey M. Spinks
Faculty of Engineering and Information Sciences - Papers: Part A
Hybrid gels featuring interpenetrating covalent and ionic crosslinked networks have recently been shown to exhibit both high toughness and recoverability of strain-induced network damage. The high toughness results from the energy dissipated as entropically strained network strands are released by the dissociation of ionic crosslinks. As in the so-called double network hydrogels, the toughening process is inherently linked to network damage. This damage, however, can be recovered to a large degree in hybrid gels due to the reformation of ionic associations when the gel is unloaded. The stability of the ionic network under load is here investigated and it is …
Collagen-Mimetic Hydrogels Promote Human Endothelial Cell Adhesion, Migration And Phenotypic Maturation, Dany J. Munoz Pinto, V. R. Guiza-Arguello, S. M. Becerra-Bayona, J. Erndt-Marino, S. Samavedi, S. Malmut, B. Russell, M. Höök, M. S. Hahn
Collagen-Mimetic Hydrogels Promote Human Endothelial Cell Adhesion, Migration And Phenotypic Maturation, Dany J. Munoz Pinto, V. R. Guiza-Arguello, S. M. Becerra-Bayona, J. Erndt-Marino, S. Samavedi, S. Malmut, B. Russell, M. Höök, M. S. Hahn
Engineering Faculty Research
This work evaluates the response of human aortic endothelial cells (HAECs) to thromboresistant collagen-mimetic hydrogel coatings toward improving the biocompatibility of existing "off-the-shelf" small-caliber vascular grafts. Specifically, bioactive hydrogels-previously shown to support α1/α2 integrin-mediated cell adhesion but to resist platelet activation-were fabricated by combining poly(ethylene glycol) (PEG) with a 120 kDa, triple-helical collagen-mimetic protein (Scl2-2) containing the GFPGER adhesion sequence. Analysis of HAECs seeded onto the resulting PEG-Scl2-2 hydrogels demonstrated that HAEC adhesion increased with increasing Scl2-2 concentration, while HAEC migration rate decreased over this same concentration range. In addition, evaluation of HAEC phenotype at confluence indicated significant differences in …
Can The Wet - State Conductivity Of Hydrogels Be Improved By Incorporation Of Spherical Conducting Nanoparticles?, Katharina Schirmer, Cody Wright, Holly Warren, Brianna C. Thompson, Anita F. Quigley, Robert M. I Kapsa, Gordon G. Wallace
Can The Wet - State Conductivity Of Hydrogels Be Improved By Incorporation Of Spherical Conducting Nanoparticles?, Katharina Schirmer, Cody Wright, Holly Warren, Brianna C. Thompson, Anita F. Quigley, Robert M. I Kapsa, Gordon G. Wallace
Australian Institute for Innovative Materials - Papers
In nerve and muscle regeneration applications, the incorporation of conducting elements into biocompatible materials has gained interest over the last few years, as it has been shown that electrical stimulation of some regenerating cells has a positive effect on their development. A variety of different materials, ranging from graphene to conducting polymers, have been incorporated into hydrogels and increased conductivities have been reported. However, the majority of conductivity measurements are performed in a dry state, even though material blends are designed for applications in a wet state, in vivo environment. The focus of this work is to use polypyrrole nanoparticles …
Edge-Hydroxylated Boron Nitride Nanosheets As An Effective Additive To Improve The Thermal Response Of Hydrogels, Feng Xiao, Sina Naficy, Gilberto Casillas, Majharu Haque Khan, Tomas Katkus, Lei Jiang, Hua-Kun Liu, Huijun Li, Zhenguo Huang
Edge-Hydroxylated Boron Nitride Nanosheets As An Effective Additive To Improve The Thermal Response Of Hydrogels, Feng Xiao, Sina Naficy, Gilberto Casillas, Majharu Haque Khan, Tomas Katkus, Lei Jiang, Hua-Kun Liu, Huijun Li, Zhenguo Huang
Australian Institute for Innovative Materials - Papers
Upon flowing hot steam over hexagonal boron nitride (h-BN) bulk powder, efficient exfoliation and hydroxylation of BN occur simultaneously. Through effective hydrogen bonding with water and N-isopropylacrylamide, edge-hydroxylated BN nanosheets dramatically improve the dimensional change and dye release of this temperature-sensitive hydrogel and thereby enhance its efficacy in bionic, soft robotic, and drug-delivery applications.
Nanocomposite Hydrogels: Fracture Toughness And Energy Dissipation Mechanisms, Andrea Klein, Philip G. Whitten, Katharina Resch, Gerald Pinter
Nanocomposite Hydrogels: Fracture Toughness And Energy Dissipation Mechanisms, Andrea Klein, Philip G. Whitten, Katharina Resch, Gerald Pinter
Australian Institute for Innovative Materials - Papers
In this study, fracture toughness of nanocomposite hydrogels is quantified, and active mechanisms for dissipation of energy of nanocomposite hydrogels are ascertained. Poly(N,N-dimethylacrylamide) nanocomposite hydrogels are prepared by in situ free radical polymerization with the incorporation of Laponite, a hectorite synthetic clay. Transmission electron microscopy proves exfoliation of clay platelets that serve as multifunctional crosslinkers in the created physical network. Extraordinary high fracture energies of up to 6800 J m-2 are determined by the pure shear test approach, which shows that these soft and stretchable hydrogels are insensitive to notches. In contrast to single- and double-network hydrogels, dynamic mechanic analysis …
Inkjet-Printed Alginate Microspheres As Additional Drug Carriers For Injectable Hydrogels, Johnson Chung, Sina Naficy, Gordon G. Wallace, Stephen O'Leary
Inkjet-Printed Alginate Microspheres As Additional Drug Carriers For Injectable Hydrogels, Johnson Chung, Sina Naficy, Gordon G. Wallace, Stephen O'Leary
Australian Institute for Innovative Materials - Papers
Local delivery of bioactive molecules to the inner ear via diffusion through the round window membrane is becoming an attractive approach to treat sensorineural hearing loss compared to systemic drug administration. Pluronics® (Lutrol F127) are a class of thermosensitive hydrogels that remain liquid prior to injection and rapidly gel under physiological conditions. They are, however, limited to short-term drug release due to rapid hydrolysis in aqueous solution. Therefore, the aim of this study was to investigate an approach, using an ink-jet printing system, to sustain the drug release by incorporating hydrogel microspheres within Lutrol F127. Various concentrations of Lutrol F127 …
Processable Conducting Graphene/Chitosan Hydrogels For Tissue Engineering, Sepidar Sayyar, Eoin Murray, Brianna Thompson, Johnson Chung, David L. Officer, Sanjeev Gambhir, Geoffrey M. Spinks, Gordon G. Wallace
Processable Conducting Graphene/Chitosan Hydrogels For Tissue Engineering, Sepidar Sayyar, Eoin Murray, Brianna Thompson, Johnson Chung, David L. Officer, Sanjeev Gambhir, Geoffrey M. Spinks, Gordon G. Wallace
Australian Institute for Innovative Materials - Papers
Composites of graphene in a chitosan-lactic acid matrix were prepared to create conductive hydrogels that are processable, exhibit tunable swelling properties and show excellent biocompatibility. The addition of graphene to the polymer matrix also resulted in significant improvements to the mechanical strength of the hydrogels, with the addition of just 3 wt% graphene resulting in tensile strengths increasing by over 200%. The composites could be easily processed into three-dimensional scaffolds with finely controlled dimensions using additive fabrication techniques and fibroblast cells demonstrate good adhesion and growth on their surfaces. These chitosan-graphene composites show great promise for use as conducting substrates …