Polymeric biomaterials for drug delivery and regenerative medicine; nano- and micro-fiber fabrication; bio-mimicking approaches for polymer flammability mitigation; polymer packaging systems design; polyelectrolyte gels and elastomers; physiologically-mimicking macromolecular constructs with attention to primitive motile and irritable systems.
- Fibrous Polymeric Materials with Applications in Medicine and Biology
“…biology is largely the study of fibers…” wrote Joseph Needham in Order and Life in 1936. Cells, tissues and organs rely on polymeric nanofibers as supporting structures, and thus polymeric fibrous scaffolds have a major role to play in the burgeoning fields of tissue engineering and regenerative medicine. Also, cell interiors and surfaces are endowed with nanofibers (the cytoskeleton) which play key roles in defining mechanical properties and various important cellular functions. For more than a decade, we have been involved in the development of electrostatic spinning (electrospinning) to create bio-mimicking fibers in a diameter range (ca. 20-100 nm) difficult to access by conventional fiber processing methods. We employ electrospinning as a method of fabrication of scaffolds for tissue engineering, drug delivery, and more recently the development of nanofiber constructs as models for functional biological systems. Major intellectual questions focus on (1) the design of nanofiber scaffolds with multi-functionality (tunable mechanical properties, porosity, ability to deliver small molecule and/or macromolecular therapeutic agents, responsiveness to stimuli, programmed degradation) and their use in 3-D cell culturing and as a materials platform to support the regeneration of tissues in vivo, and (2) the prospect of designing and building functional biological systems such as muscle and nerve based upon an abiotic combination of nanofibers and appropriate colloids and gels that may at least crudely mimic the earliest examples of ‘life.’
- Biofilms: A New Macromolecular Perspective
A biofilm is a complex mixture of macromolecules that colonies of many types of bacteria and fungi generate and use great advantage for survival. Biofilms are notorious in a wide variety of settings, from hospitals to industrial plants, and inhibition of their formation is major challenge. We are interested in the concept of a biofilm as a ‘macro-cell’ where the matrix is roughly viewed as a kind of protoplasm containing many individual cells. Of particular interest is what functions the matrix serves to facilitate resistance of cell colonies to treatment by antibiotics and other chemical agents. The state of water in and around biofilms is being studied using a variety of advanced imaging techniques to address this issue with the ultimate goal of gaining insight on how to effectively defeat biofilm formation and bacterial or fungal cell colony sustenance. Sorption by the biofilm and partitioning of various external chemical species, specifically ions and small organic molecules, is also an area of interest.
- Microfluidics and Sensors
We have helped to develop a new approach to 'lab-on-a-chip' microfluidic devices based on 2-D printing of hydrophilic paths on otherwise hydrophobic surfaces and bringing two such surface in close proximity without actual contact. Water will wet the hydrophilic paths and be drawn along them by capillary action, yet the sidewalls are in contact with air and thus the water channels are confined by the fluid's surface tension. An attractive feature of this approach is that all paths can be easily printed on inexpensive materials rather than inscribed as 3-D channels as is the case with conventional microfluidic devices. Another attribute is that reactive reagents can be 'spotted' along the paths by printing, affording a simple means to fabricate complex assay systems.
- C. J. Miller, C. A. Zorman and G. E. Wnek, “An Improved Tactile Sensing Device for Material Characterization via Friction-Induced Vibrations and Roughness,” Sensors and Actuators A: Physical, in press
- C. Souza, J. Feng, G. Wnek, A. Olah and E. Baer, “Thermoformable High Oxygen-Barrier EVOH/LDPE Film/Foam,” J. Appl. Polym. Sci., in press
- G. A. Samid and G. E. Wnek, “Prospective: The ‘Rock of Randomness’- A Physical Oracle for Securing Data off the Digital Grid,” MRS Communications, doi:10.1557/mrc.2019.8 (2019)
- A. Y. Walker, M. A. Vratsanos, T. D. Askew, K. D. Hemmendinger, S. K. Kozawa and G. E. Wnek, “Enhanced Elasticity of Poly(Acrylic Acid) Gels via Synthesis in the Presence of High Concentrations of Selected Salts,” Soft Matter, DOI: 10.1039/c9sm01101c (2019)
- D. J. Brannum, E. J. Price, D. Villamil, M. Brannum, S. K. Kozawa, C. Berry, R. Semco, and G. E. Wnek, “Flame-Retardant Polyurethane Foams: One-Pot, Bioinspired Silica Nanoparticle Coating,” ACS Applied Polymer Materials, DOI 10.1021/acsapm.9b00283 (2019)
- M. T. Brannum, A. M. Steele, M. C. Venetos, L. T. J. Korley, G. E. Wnek and T. J. White, “Light Control with Liquid Crystalline Elastomers,” Adv. Optical Mater., DOI: 10.1002/adom.201801683 (2019)
- X. Wang, X. Li, C. Grimme, A. Olah, E. Baer and G. E. Wnek, “Fabrication of Surlyn® Ionomer Microfibers Using a Novel Co-Extrusion and Multiplication Approach,” J. Appl. Polym. Sci., doi/abs/10.1002/app.48046 (2019)
- M. Mehregany and G. E. Wnek, “Opinion: Principles to Guide Leadership Training,” ASEE Prism (Last Word), May/June 2019
- M. T. Brannum, A. D. Auguste, B. R. Donovan, N. P. Godman, V. M. Matavulj, A. M. Steele, L. T. J. Korley, G. E. Wnek and T. J. White,“Deformation and Elastic Recovery of Acrylate-based Liquid Crystalline Elastomers,” Macromolecules, https://pubs.acs.org/doi/full/10.1021/acs.macromol.9b01092 (2019)
- M. Mofidfar, E.S. Kim, E. L. Larkin, L. Long, W. D. Jennings, S. Ahadian, M. Ghannoum and G. E. Wnek, " Antimicrobial Activity of Silver Containing Crosslinked Poly(Acrylic Acid) Fibers,” Micromachines, 10, 829 (2019) (Special Issue Micro- and Nanotechnologies for Medicine: Emerging Frontiers and Applications 2019)