Progress 09/01/05 to 08/31/09
Outputs
OUTPUTS: Directed self-assembly of zein and possibly other proteins may be useful in controlling the spatial distribution of cells on a surface. This process may find an application in the construction of scaffolding for tissue engineering. Results of this research were presented in the classroom, in departmental seminars, at scientific meetings, and published in scientific journals. PARTICIPANTS: Graciela Padua, Department of Food Science and Human Nutrition, University of Illinois. Qin Wang, now at Department of Nutrition and Food Science at the University of Maryland. Chang Liu, Department of Mechanical Engineering, Northwestern University. Leilei Yin, Beckman Institue, University of Illinois. Qian Wang, University of Illinois. Xuejun Wang, University of Illinois. Wujing Xian, University of Illinois. Shifeng Li, University of Illinois. TARGET AUDIENCES: Academic and industry researchers and students interested in the design and characterization of biomaterials. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The topography and biocompatibility of zein layers adsorbed on patterned templates containing hydrophilic and hydrophobic regions were investigated. Nanopatterned templates consisting of hydrophilic lines on a hydrophobic background were drawn by dip-pen nanolithography (DPN) on gold-coated surfaces. Zein was allowed to adsorb on patterned surfaces from alcohol-water solutions. The topography of zein deposits was observed by atomic force microscopy (AFM). Height profiles from AFM measurements revealed that zein deposits followed closely the nanopatterned templates. To investigate the biocompatibility of micropatterned zein layers, templates containing hydrophilic and hydrophobic regions were generated by micro-contact printing. Mouse fibroblasts seeded on patterned zein layers proliferated on zein deposited over hydrophilic regions, but not on hydrophobic ones. The experiment indicated that fibroblast cells responded to variations in the surface chemistry generated by the different orientation adopted by zein on the two substrates. The possibilities of guiding the self-assembly of zein at the sub-micron level and using DPN and micro-contact printing to enable this process are novel concepts.
Publications
- Wang, Q., Xian, W., Li, S., Liu, C. and Padua, G.W. 2008. Topography and biocompatibility of patterned hydrophobic/hydrophilic zein layers. Acta Biomaterialia. 4 (4 ): 844-851.
- Padua, G.W. 2009. Soft matter approach to zein-based food structures. Conference of Food Engineering. April 7, 2009, Columbus, OH.
- Padua, G.W. 2009. Zein nanofabricated biomaterials for tissue scaffolding. Proceedings of the USDA Grantees Meeting. September 27-28, 2009, Santa Fe, NM.
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Progress 09/01/07 to 08/31/08
Outputs
OUTPUTS: Activities: 1) Conducting experiments as reported in the publications section. 2) Mentoring of a post-doctoral associate who became an Assistant Professor at the University of Maryland. Events include attendance at: 1) AIChE Annual Meeting Nov 12-17, 2006 San Francisco, CA. with presenting "Cell growth on zein surfaces self-assembled on patterned templates" in Topical Conference "The U.S.-Japan Joint Topical Conference on Medical Engineering, Drug Delivery Systems and Therapeutic Systems". 2) ACS 233th National Meeting, Chicago, IL March 25-29, 2007 presenting "Controlled self-organization of zein nanostructures for encapsulation of active food ingredients" in "Micro/Nano Encapsulation of Active Food Ingredients". 3) 2nd International Symposium on Delivery of Functionality in Complex Food Systems: Physically-Inspired Approaches From Nanoscale to Microscale, Amherst, MA October 8-10, 2007 presenting "Multi-scale self-assembly of zein structures". 4) AIChE Annual Meeting. Salt Lake City, UT November 4-9, 2007 presenting "Zein controlled micro- and nano-structures for food applications". Services include consulting which has taken place with several industry groups on zein properties and behavior for a variety of potential industrial and consumer applications. Products include a 3D video animation that was produced in collaboration with Parkland College of Champaign, IL that illustrates the process of protein self-assembly. This video is intended for incorporation in protein chemistry courses for undergraduate and graduate students and for discovery seminars and presentations for undergraduates and high school students. Dissemination activities include the generation of materials for the publication of USDA Partners Video Magazine, Episode 21 "The Science of Small", Preview: Researchers are exploring the power of nanotechnolgy . Segment "New Skin". The piece is posted on line at: www.csrees.usda.gov/newsroom/partners/21/nanotechnology.html. Also, DVDs were distributed to schools and farming organizations. PARTICIPANTS: Dr. Qin Wang was a post-doctoral research associate in this poject. She is now at the University of Maryland. TARGET AUDIENCES: Students and researchers in industry and academia interested in nanotechnology, biopolymers, protein self-assembly, tissue scaffolding, and microencapsulation. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Change in knowledge: New qualitative models were proposed to explain protein-protein interaction and self-assembly. The model proposes that zein self-assembly is guided by hydrophobic interactions and van der Waals forces, the rate of self-assembly and the ultimate structure of the aggregate will depend on the hydrophobic/hydrophilic balance of the solvent medium. Thus, structure development and architecture can be guided by adding or removing surface active components from the medium. For example, zein can be dispersed in alcohol-water mixtures, the exact nature of the structure adopted by zein will depend on the alcohol used in the solvent as well as its concentration. These new models can be used, in the near future, to predict protein behavior and design novel structures such as layers for scaffolding in tissue engineering and novel food components such as encapsulation systems and functional matrices for bioactive compounds. Change in actions: A new interest in zein as a biopolymer has developed among researchers in industry and academia as a result of new knowledge generated in this and other projects. A number of possible applications are currently being evaluated ranging from tissue engineering scaffolding to microencapsulation systems and biodegradable plastic goods and packaging materials.
Publications
- Abstracts: Wang, Q., Li, S., Liu, C., Padua, GW. 2006 Cell Growth on zein surfaces self-assembled on patterned templates. Topical Conference The US-Japan Joint Topical Conference on Medical Engineering, Drug Delivery Systems and Therapeutic Systems. Proceedings of the 2006 AIChE Annual Meeting Nov 12-17, 2006 San Francisco, CA
- Padua, GW and Wang, Q. 2007 Controlled self-organization of zein nanostructures for encapsulation of active food ingredients. In Micro/Nano Encapsulation of Active Food Ingredients. Eds. P. Given, Q. Huang, and M. Qian. Proceedings of the ACS 233th National Meeting, Chicago, IL March 25-29, 2007.
- Journal papers: Wang Q, Wang Q, Wang XJ, and Padua GW. 2006. Zein dynamic adsorption to carboxylic and alkyl coated surfaces. J. Agric. Food Chem. 54 (2): 517-522.
- Wang, Q., Yin, L., Padua, G.W. 2008 Effect of Hydrophilic and Lipophilic Compounds on Zein Microstructures. Food Biophysics 3:174-181.
- Padua, G.W., Wang, Q. 2007 Multi-scale self-assembly of zein structures. 2nd International Symposium on Delivery of Functionality in Complex Food Systems: Physically-Inspired Approaches Nanoscale to Microscale. Amherst, MA October 8-10, 2007. Wang, Q., Yin, L., Padua, G.W. 2007 Zein controlled micro- and nano-structures for food applications. AIChE Annual Meeting. Salt Lake City UT November 4-9, 2007.
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Progress 09/01/06 to 08/31/07
Outputs
OUTPUTS: The topography and biocompatibility of zein layers adsorbed on patterned templates containing hydrophilic and hydrophobic regions was investigated. Nanopatterned templates consisting of hydrophilic lines on a hydrophobic background were drawn by dip-pen nanolithography (DPN) on gold coated surfaces. 16-mercaptohexadecanoic acid (COOH(CH2)15SH, MHA) was used as primary ink to generate hydrophilic lines. Unpatterned surfaces were backfilled with 18-octadecanethiol (CH3(CH2)17SH, ODT), which generated hydrophobic regions. Zein was allowed to adsorb on patterned surfaces from alcohol-water solutions. The topography of zein deposits was observed by atomic force microscopy (AFM). Height profiles from AFM measurements revealed that zein deposits followed closely the nanopatterned templates. The biocompatibility of zein layers assembled over hydrophilic/hydrophobic micropatterned templates was investigated. Templates containing MHA lines and ODT regions were generated by
micro-contact printing. Mouse fibroblasts seeded on patterned zein layers proliferated on zein deposited over MHA lines, but not on zein over ODT. The experiment indicated that fibroblast cells were able to respond to variations in the underlying surface chemistry, transmitted by the different orientation adopted by zein on the different substrates. This property may be useful in controlling the spatial distribution of cells on patterned protein layers.
PARTICIPANTS: Graciela W. Padua, Department of Food Science and Human Nutrition, University of Illinois. Chang Liu, Dept. of Mechanical Engineering, Northwestern University. Qin Wang, Department of Food Science and Human Nutrition, University of Illinois. Shifeng Li, Dept. of Mechanical Engineering, Northwestern University. Wujing Xian, Department of Materials Science and Engineering, University of Illinois.
TARGET AUDIENCES: Researchers and students in universities, medical institutes, government agencies working in tissue engineering.
Impacts
Zein nanoscale structures were built on MHA/ODT templates patterned on gold surfaces by DPN. Differences in morphology between zein deposits over MHA and ODT were observed. Zein formed high rising structures on MHA and low-lying deposits on ODT. Topographical features of zein deposits, as observed by AFM, were clearly defined. The experiment indicated that zein responds sharply to the polar character of adsorbing surfaces and thus enabled the investigation of cell attachment to zein layers of varied surface chemistry. Micropatterned surfaces having hydrophilic and hydrophobic regions were generated by micro-contact printing. Zein self-assembled on such patterned surfaces generating a secondary template which was used for growing fibroblast cells. Cell growth on patterned zein layers was confined to areas where zein was adsorbed on MHA. In contrast, zein adsorbed on ODT showed limited cell growth. The experiment indicated that fibroblast cells were able to respond to
the underlying surface chemistry, which was transmitted by the different orientation adopted by zein on the different substrates. It was suggested that zein may be used to control the spatial location, orientation, and morphology of seeded cells. A controlled microenvironment is considered critical in the development of engineered tissues. Further work is needed to generate micropatterned surfaces on soft materials and form 3D structures either by layer-by-layer construction or other enabling technologies.
Publications
- Wang, Q., Xian, W., Li, S., Liu, C. and Padua, G.W. 2007. Topography and biocompatibility of patterned hydrophobic/hydrophilic zein layers. (Forthcoming).
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Progress 09/01/05 to 08/31/06
Outputs
Zein adsorption on nanopatterned templates containing hydrophilic and hydrophobic regions was investigated. Nanopatterns consisting of lines, dots, and grids were generated by dip-pen nanolithography using 16-mercaptohexadecanoic acid as primary ink and 18-octadecanethiol as backfill ink. Zein was allowed to adsorb on patterned surfaces from ethanol-water solutions. The topography of zein deposits was observed by atomic force microscopy. Zein followed closely the template of nanopatterned surfaces and self-assembled into high raised structures on -COOH surfaces but showed low laying coverage on -CH3 surfaces. Resulting zein patterns showed a high degree of edge definition resulting from effective nanopatterning and the ability of zein molecules to orient themselves and self-assemble according to the ink character. Zein supramolecular structures may find application in construction of cell growth scaffolding.
Impacts
Micro and nanopatterning of proteins and other biomolecules on to various surfaces is currently a focus of attention, linked to the development of biosensors and tissue scaffolding. Patterning is expected to produce templates that control the spatial distribution of attaching biochemicals and cells. Dip-pen nanolithography (DPN) is a novel technique used to form patterns of chemical compounds with nanoscale precision. In this work, zein was used to produce a layer of protein of hybrid of a hydrophilic/hydrophobic surface. Patterned protein layers are expected to find application in the construction of self-assembled structures. Zein self-assembly properties, biocompatibility, and biodegradability make it a promising material for construction of tissue scaffolding and drug delivery vehicles.
Publications
- No publications reported this period
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