Nanomanufacturing of Biopolymer Nanofiber Hierarchical Assemblies

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Immediate cellular environment, commonly referred to as the extracellular matrix, consists of micro/nanofibers (diameter: microns to sub-100 nanometers) and serves as a scaffold upon which most cells in the body attach and receive mechanical and chemical cues. An increased awareness of the role of alignment in extracellular matrix-cell interactions and the role of biophysical cues in development and disease models including cancer has necessitated the development of fiber manufacturing technologies mimicking the native environments for in vivo translational and in vitro cell behavior studies. Electrospinning is the most commonly used manufacturing method to fabricate nanofibers. However, it still lacks precise control on fiber diameter, spacing and orientation. This award utilizes a non-electrospinning fiber manufacturing platform to architect precise biophysical environments for cell studies through improved spinnability of biopolymers with control on fiber diameter, spacing and orientation in multiple layers. The resulting constructs can be instrumental in developing implantable scaffolds for tissue engineering, and single cell diagnostic platforms. Therefore, results from this research will benefit the U.S. economy and society. This multidisciplinary research involves elements from disciplines such as manufacturing, polymer physics, biology, mechanics and mechanical engineering. The award will help broaden participation of underrepresented groups in engineering research and positively impact engineering education at both undergraduate and graduate levels.The physics of polymer fiber formation at the nanoscale involves a delicate balance between solution rheology and applied external forces, which makes nanomanufacturing and hierarchical assembly of nanofibers extremely challenging. To augment our capabilities in fiber manufacturing, a non-electrospinning nanofiber manufacturing platform will be used to study fiber spinnability in this work. Due to elimination of electric source in the manufacturing process, the platform will provide superior control on fiber diameter, orientation, spacing and assembly, particularly in multiple layers. Using poly (lactic-co-glycolide acid) and fibrinogen as model polymer systems, this project will develop fiber spinnability scaling laws representing fiber diameter design space spanning a wide range of solution rheologies and processing parameters. Furthermore, mechanical tensile testing of single fibers using atomic force microscopy at different strain rates will provide the fiber probability failure Weibull distributions in the manufacturing process. This research will fill the knowledge gap on the spinnability of biopolymers and for the first time provide the ability to manufacture custom architectures representing gradients in biophysical cues. The overall research will thus provide a roadmap to design and build scaffolds of biopolymers with improved quality, scalability and repeatability.