@article{cao_guenther_sit_lommel_opperman_willoughby_2015, title={Development of Abamectin Loaded Plant Virus Nanoparticles for Efficacious Plant Parasitic Nematode Control}, volume={7}, ISSN={1944-8244 1944-8252}, url={http://dx.doi.org/10.1021/ACSAMI.5B00940}, DOI={10.1021/acsami.5b00940}, abstractNote={Plant parasitic nematodes are one of the world's major agricultural pests, causing in excess of $157 billion in worldwide crop damage annually. Abamectin (Abm) is a biological pesticide with a strong activity against a wide variety of plant parasitic nematodes. However, Abm's poor mobility in the soil compromises its nematicide performance because of the limited zone of protection surrounding the growing root system of the plant. In this study, we manipulated Abm's soil physical chemistry by encapsulating Abm within the Red clover necrotic mosaic virus (RCNMV) to produce a plant virus nanoparticle (PVN) delivery system for Abm. The transmission electron microscopic and dynamic light scattering characterization of Abm-loaded PVN (PVN(Abm)) indicated the resultant viral capsid integrity and morphology comparable to native RCNMV. In addition, the PVN(Abm) significantly increased Abm's soil mobility while enabling a controlled release strategy for Abm's bioavailability to nematodes. As a result, PVN(Abm) enlarged the zone of protection from Meloidogyne hapla root knot nematodes in the soil as compared to treating with free Abm molecules. Tomato seedlings treated with PVN(Abm) had healthier root growth and a reduction in root galling demonstrating the success of this delivery system for the increased efficacy of Abm to control nematode damage in crops.}, number={18}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Cao, Jing and Guenther, Richard H. and Sit, Tim L. and Lommel, Steven A. and Opperman, Charles H. and Willoughby, Julie A.}, year={2015}, month={May}, pages={9546–9553} }
 @article{cao_guenther_sit_opperman_lommel_willoughby_2014, title={Loading and Release Mechanism of Red Clover Necrotic Mosaic Virus Derived Plant Viral Nanoparticles for Drug Delivery of Doxorubicin}, volume={10}, ISSN={["1613-6829"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84919761332&partnerID=MN8TOARS}, DOI={10.1002/smll.201400558}, abstractNote={Loading and release mechanisms of Red clover necrotic mosaicvirus (RCNMV) derived plant viral nanoparticle (PVN) are shown for controlled delivery of the anticancer drug, doxorubicin (Dox). Previous studies demonstrate that RCNMV's structure and unique response to divalent cation depletion and re‐addition enables Dox infusion to the viral capsid through a pore formation mechanism. However, by controlling the net charge of RCNMV outer surface and accessibility of RCNMV interior cavity, tunable release of PVN is possible via manipulation of the Dox loading capacity and binding locations (external surface‐binding or internal capsid‐encapsulation) with the RCNMV capsid. Bimodal release kinetics is achieved via a rapid release of surface‐Dox followed by a slow release of encapsulated Dox. Moreover, the rate of Dox release and the amount of released Dox increases with an increase in environmental pH or a decrease in concentration of divalent cations. This pH‐responsive Dox release from PVN is controlled by Fickian diffusion kinetics where the release rate is dependent on the location of the bound or loaded active molecule. In summary, controllable release of Dox‐loaded PVNs is imparted by 1) formulation conditions and 2) driven by the capsid's pH‐ and ion‐ responsive functions in a given environment.}, number={24}, journal={SMALL}, publisher={Wiley}, author={Cao, Jing and Guenther, Richard H. and Sit, Tim L. and Opperman, Charles H. and Lommel, Steven A. and Willoughby, Julie A.}, year={2014}, month={Dec}, pages={5126–5136} }
 @article{tambe_cao_xu_willoughby_2014, title={Surface design, fabrication and properties of silicone materials for use in tissue engineering and regenerative medicine}, DOI={10.1002/9781118938478.ch23}, abstractNote={This chapter contains sections titled: Introduction Silicone Biomaterials Silicones in Tissue Engineering Surface Characterization Techniques Conclusion and Outlook Acknowledgement}, journal={Concise encyclopedia of high performance silicones}, author={Tambe, N. and Cao, J. and Xu, K. W. and Willoughby, J. A.}, year={2014}, pages={355–369} }
 @inproceedings{grewal_willoughby_2013, title={Organic surface modifications on silicone elastomers: Impact on moisture vapor permeability and surface energy dynamics}, volume={1154}, DOI={10.1021/bk-2013-1154.ch009}, abstractNote={The purpose of this study was to observe the effects of organic surface modifications on silicone elastomers with respect to moisture vapor permeability properties as a function of both grafted moiety functionality and packing density. We utilized chemical vapor deposition and mechanical manipulation of the elastomer to deposit (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane and 3-aminopropyltrimethoxysilane. As expected, the chemical vapor deposition of both species altered the chemistry of the elastomer surface to more hydrophobic for the fluorinated silane and more hydrophilic for the amino - terminated silane in the absence of mechanical elongation during the modification. As previously demonstrated, increasing the packing density of the silanes by increasing the degree of tension on the substrate during activiation and deposition, resulted in an increase in the contact angle of water. This turned out to be true even for the hydrophilic species. In all modified samples, the moisture vapor permeability (MVP) decreased by about 50% and is attributed to the ultraviolet/ ozone activation step that created a silica-like layer. Despite the reduction in MVP, the modified elastomer films are still considered to have a high moisture vapor permeability on the order of 5·10-1 g·mm/m2·hr·kPa.}, booktitle={Progress in silicones and silicone-modified materials}, author={Grewal, R. and Willoughby, J. A.}, year={2013}, pages={113–132} }
 @article{honarbakhsh_guenther_willoughby_lommel_pourdeyhimi_2013, title={Polymeric Systems Incorporating Plant Viral Nanoparticles for Tailored Release of Therapeutics}, volume={2}, ISSN={["2192-2659"]}, DOI={10.1002/adhm.201200434}, abstractNote={AbstractTherapeutic polylactide (PLA) nanofibrous matrices are fabricated by incorporating plant viral nanoparticles (PVNs) infused with fluorescent agents ethidium bromide (EtBr) and rhodamine (Rho), and cancer therapeutic doxorubicin (Dox). The native virus, Red clover necrotic mosaic virus (RCNMV), reversibly opens and closes upon exposure to the appropriate environmental stimuli. Infusing RCNMV with small molecules allows the incorporation of PVNActive into fibrous matrices via two methods: direct processing by in situ electrospinning of a polymer and PVNs solution or immersion of the matrix into a viral nanoparticle solution. Five organic solvents commonly in‐use for electrospinning are evaluated for potential negative impact on RCNMV stability. In addition, leakage of rhodamine from the corresponding PVNRho upon solvent exposure is determined. Incorporation of the PVN into the matrices are evaluated via transmission electron, scanning electron and fluorescent microscopies. Finally, the percent cumulative release of doxorubicin from both PLA nanofibers and PLA and polyethylene oxide (PEO) hybrid nanofibers demonstrate tailored release due to the incorporation of PVNDox as compared to the control nanofibers with free Dox. Preliminary kinetic analysis results suggest a two‐phase release profile with the first phase following a hindered Fickian transport mechanism for the release of Dox for the polymer‐embedded PVNs. In contrast, the nanofiber matrices that incorporate PVNs through the immersion processing method followed a pseudo‐first order kinetic transport mechanism.}, number={7}, journal={ADVANCED HEALTHCARE MATERIALS}, author={Honarbakhsh, Sara and Guenther, Richard H. and Willoughby, Julie A. and Lommel, Steven A. and Pourdeyhimi, Behnam}, year={2013}, month={Jul}, pages={1001–1007} }
 @inproceedings{grewal_sweesy_jur_willoughby_2012, title={Moisture vapor barrier properties of biopolymers for packaging materials}, volume={1107}, DOI={10.1021/bk-2012-1107.ch015}, abstractNote={We present a review of current research focused on the use of biopolymers as viable packaging materials. We discuss polysaccharides, proteins, lipids, materials systems comprising edible coatings, and inorganic surface modification processes as they impact moisture barrier permeability properties. We give an overview of the fundamental factors that affect moisture vapor permeability (MVP), provide an overview of barrier properties for typical packaging materials on a common unit basis, and the MVP improvements made with evolving techniques. We explore some challenges and unknowns with surface modifications specific to altering the barrier properties of polymers derived from renewable resources. We provide some of the future directions in our own work to improve materials with inherently poor moisture vapor properties using the insights from this review as a road map.}, booktitle={Functional materials from renewable sources}, author={Grewal, R. and Sweesy, W. and Jur, J. S. and Willoughby, J.}, year={2012}, pages={271–296} }
 @article{crowe-willoughby_weiger_ozcam_genzer_2010, title={Formation of silicone elastomer networks films with gradients in modulus}, volume={51}, ISSN={["0032-3861"]}, DOI={10.1016/j.polymer.2009.11.070}, abstractNote={We describe the formation of soft material substrates with position-dependent modulus. Two strategies have been employed in the preparation of such materials. In the first method, we create modulus gradient structures by inter-diffusing two (or more) formulations of silicone elastomers (SE), comprising mixtures of poly(dimethylsiloxane) (PDMS) and poly(vinylmethylsiloxane) (PVMS) with varying molecular weight and content of PDMS, and cross-link them thermally in order to form SE networks. With this method, the resultant substrates exhibit shallow modulus gradients that extend over a few centimeters in length. The second technique is based on employing ultraviolet (UV)-based cross-linking of mercapto-terminated PVMS chains across transparency lithographic masks. We demonstrate that the shape and "sharpness" of the modulus on the substrate depends solely on the position-dependent transparency of the mask to the UV light. As a part of the study we provide detailed material characterization of networks formed by the PDMS–PVMS and PVMS-SH chains.}, number={3}, journal={POLYMER}, author={Crowe-Willoughby, Julie A. and Weiger, Katherine L. and Ozcam, Ali E. and Genzer, Jan}, year={2010}, month={Feb}, pages={763–773} }
 @article{crowe-willoughby_stevens_genzer_clarke_2010, title={Investigating the Molecular Origins of Responsiveness in Functional Silicone Elastomer Networks}, volume={43}, ISSN={["1520-5835"]}, DOI={10.1021/ma100470w}, abstractNote={Dielectric, calorimetric, and dynamic mechanical measurements were performed to delineate the types and dynamic rates of molecular scale motion in modified poly(vinylmethyl siloxane) (PVMS) stimuli-responsive networks, where pendent groups of the form -S-(CH2)n-OH were chemically attached to the vinyl moiety of PVMS. The glass transition temperature (Tg) for the unsubstituted PVMS network matches that previously reported for linear PVMS indicating that the flexibility of the polymer chains is unaffected by the network cross-linking. In contrast, Tg increases with the introduction of pendent groups of the type -S-(CH2)n-CH3 or -S-(CH2)n-OH, where n is 2, 6, or 11, as the different groups constrain the siloxane backbone to differing degrees. The macroscopic response time and amplitude, as previously measured bydynamic contactangle,arecorrelated withtheobservedglass transition temperatures. Onecon- clusion is that the flexibility of the network and the interactions between pendent groups affect responsiveness.}, number={11}, journal={MACROMOLECULES}, author={Crowe-Willoughby, Julie A. and Stevens, Derrick R. and Genzer, Jan and Clarke, Laura I.}, year={2010}, month={Jun}, pages={5043–5051} }
 @article{crowe-willoughby_genzer_2009, title={Formation and Properties of Responsive Siloxane-Based Polymeric Surfaces with Tunable Surface Reconstruction Kinetics}, volume={19}, ISSN={["1616-3028"]}, DOI={10.1002/adfm.200800622}, abstractNote={AbstractHere, the formation of responsive polymeric materials with tunable response time is reported. These structures are fabricated by chemically modifying poly(vinylmethyl siloxane) (PVMS) networks with alkanethiols bearing a hydrophilic end‐group (COOH or OH). The response time is facilitated by the liquid nature of the PVMS backbone and increases with increase in length of the methylene spacer (CH2)n in the alkanethiol pendent group. While for n = 2 and 6, the surface reconstructs almost instantaneously, specimens with n = 11 resist reconstruction because of strong van der Waals forces, leading to the formation of semi‐crystalline regions. It is demonstrated that the responsive nature of PVMSS(CH2)11OH can be fine‐tuned by varying the temperature; it possesses a faster response at temperatures above the melting point of the S(CH2)11OH moiety.}, number={3}, journal={ADVANCED FUNCTIONAL MATERIALS}, author={Crowe-Willoughby, Julie Ann and Genzer, Jan}, year={2009}, month={Feb}, pages={460–469} }
 @inproceedings{crowe_efimenko_genzer_2007, title={Manipulating siloxane surfaces: Obtaining the desired surface function via engineering design}, volume={964}, DOI={10.1021/bk-2007-0964.ch015}, abstractNote={We present a synopsis of recent accomplishment in our group in the area of surface-functionalized silicone elastomer networks. Specifically, we show that by combining mechanical manipulation of poly(dimethylsiloxane) (PDMS) networks with activation via ultraviolet/ozone (UVO) treatment and subsequent chemical modification of the preactivated surfaces, one can generate so-called mechanically assembled monolayers (MAMs). This technology can be successfully applied to create a variety of surfaces, including dense polymer brushes, long-lived superhydrophobic surfaces, molecular gradients comprising tunable length scales and two-dimensional chemical gradients. In addition, the UVO modification of mechanically strained PDMS sheets provides a convenient route for creating "buckled" elastomeric sheets. These surfaces have a multitude of applications; ranging from anti-fouling surfaces to directed particle assembly. Finally we demonstrate control of surface wettability and responsiveness using poly(vinylmethylsiloxane) (PVMS) networks. We have shown that PVMS surfaces can be chemically tailored by reacting with thiols. The degree of response (including response rate) of such surfaces to hydrophobic-hydrophilic interactions can be adjusted by varying the chemical and structural properties of the side-group modifiers.}, booktitle={Science and technology of silicones and silicone-modified materials}, author={Crowe, J. A. and Efimenko, Kirill and Genzer, Jan}, year={2007}, pages={222–255} }
 @inbook{crowe_efimenko_genzer_schwark_2006, title={Responsive siloxane-based polymeric surfaces}, ISBN={0813821096}, booktitle={Responsive polymer materials: Design and applications}, publisher={Ames, Iowa: Blackwell Publishing}, author={Crowe, J. A. and Efimenko, K. and Genzer, J. and Schwark, D. W.}, year={2006}, pages={184} }
 @article{crowe_genzer_2005, title={Creating responsive surfaces with tailored wettability switching kinetics and reconstruction reversibility}, volume={127}, ISSN={["0002-7863"]}, DOI={10.1021/ja056926u}, abstractNote={We report on the formation of responsive surfaces with tailorable surface reconstruction kinetics and switching hysteresis by thiolene radical addition of mercaptoalkanols with variable lengths to poly(vinylmethylsiloxane) networks. Exposing these elastomer surfaces to water results in rearrangement of the hydrophilic alkanes at the surface. The rearrangement kinetics decreases with increasing number of the methylene spacers (n) in the mercaptoalkanol. The response kinetics is found to be very fast for n = 2 and 6. For instance, upon exposing to water, the water contact angle on 3-mercaptopropanol-based surfaces decreases by approximately 35 degrees at the rate of 2 degrees /s. The high flexibility of the siloxane backbone endows these materials with switching longevity; the materials were able to switch their wettability over 10 cycles with minimum hysteresis. Increasing the number of methylene spacers to n = 11 decreases the surface reorganization dramatically. Formation of semicrystalline regions in such materials (detected via IR) is responsible for initial "sluggish" kinetics and eventual surface "freezing".}, number={50}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Crowe, JA and Genzer, J}, year={2005}, month={Dec}, pages={17610–17611} }
 @article{burns_burroughs_gracz_pritchard_brozena_willoughby_khan, title={Cyclodextrin facilitated electrospun chitosan nanofibers}, volume={5}, number={10}, journal={RSC Advances}, author={Burns, N. A. and Burroughs, M. C. and Gracz, H. and Pritchard, C. Q. and Brozena, A. H. and Willoughby, J. and Khan, S. A.}, pages={7131–7137} }