Showing papers by "Caroline L. Schauer published in 2015"

An electrospun PVDF-TrFe fiber sensor platform for biological applications

Abstract: Flexible, self-powered materials are in demand for a multitude of applications such as energy harvesting, robotic devices, and lab-on-a chip medical diagnostics. Electrospinning piezoelectric fluoropolymers into nanofibers can provide these functionalities in a facile method. PVDF-TrFe was electrospun in an aligned format and interfaced with a flexible plastic substrate in order to create a platform for voltage response characterization after small force cantilever deformations. Voltage peak signals were an average of ±0.4 V, and this response did not change after platform sterilization. However, when placed in cell culture media, piezoelectric response was dampened. This platform can be used for measurement and analysis of electromechanical behavior in a variety of applications, including cellular-powered nanodevices.

Self-Folding Textiles through Manipulation of Knit Stitch Architecture

Abstract: This research presents a preliminary study on finding predictable methods of controlling the self-folding behaviors of weft knit textiles for use in the development of smart textiles and garment devices, such as those with shape memory, auxetic behavior or transformation abilities. In this work, Shima Seiki SDS-One Apex computer-aided knitting technology, Shima Seiki industrial knitting machines, and the study of paper origami tessellation patterns were used as tools to understand and predict the self-folding abilities of weft knit textiles. A wide range of self-folding weft knit structures was produced, and relationships between the angles and ratios of the knit and purl stitch types were determined. Mechanical testing was used as a means to characterize differences produced by stitch patterns, and to further understand the relationships between angles and folding abilities. By defining a formulaic method for predicting the nature of the folds that occur due to stitch architecture patterns, we can better design self-folding fabrics for smart textile applications.

Osteoblast biocompatibility of premineralized, hexamethylene-1,6-diaminocarboxysulfonate crosslinked chitosan fibers.

Abstract: Biopolymer–ceramic composites are thought to be particularly promising materials for bone tissue engineering as they more closely mimic natural bone. Here, we demonstrate the fabrication by electrospinning of fibrous chitosan-hydroxyapatite composite scaffolds with low (1 wt %) and high (10 wt %) mineral contents. Scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and unidirectional tensile testing were performed to determine fiber surface morphology, elemental composition, and tensile Young's modulus (E) and ultimate tensile strength (σUTS), respectively. EDS scans of the scaffolds indicated that the fibers, crosslinked with either hexamethylene-1,6-diaminocarboxysulfonate (HDACS) or genipin, have a crystalline hydroxyapatite mineral content at 10 wt % additive. Moreover, FESEM micrographs showed that all electrospun fibers have diameters (122–249 nm), which fall within the range of those of fibrous collagen found in the extracellular matrix of bone. Young's modulus and ultimate tensile strength of the various crosslinked composite compositions were in the range of 116–329 MPa and 2–15 MPa, respectively. Osteocytes seeded onto the mineralized fibers were able to demonstrate good biocompatibility enhancing the potential use for this material in future bone tissue engineering applications. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3201–3211, 2015.

Osteoblast biocompatibility of novel chitosan crosslinker, hexamethylene-1,6-diaminocarboxysulfonate.

Abstract: Chitosan is a naturally occurring polysaccharide, which has proven to be an attractive candidate for bone tissue engineering, due to its ability to promote osteoblast mineralization. Electrospinning has become a well-established cell scaffold processing technique, as it produces a high surface area to volume fibrous material that can mimic the three dimensionality of the extracellular matrix of a cell. In this study, we have investigated the osteoblast response to two different chemically crosslinked (hexamethylene-1,6-diaminocarboxysulfonate (HDACS) and genipin) electrospun chitosan scaffolds and their film counterparts in order to determine how material chemistry influences cellular behavior in conjunction with material topology. In addition, material properties of each fiber scaffold such as porosity and tensile strength were considered. MLO-A5 osteoblast cells grown on chitosan-HDACS scaffolds were found to display a more organized cellular network, along with significantly more filopodia extensions, compared to those grown on chitosan-genipin scaffolds. After 2 days of growth on chitosan-HDACS fibers, a higher level of alkaline phosphatase expression in MLO-A5 cells was reported compared to that of either chitosan-genipin fibers or films. These results indicate that not only chemistry, but also surface topology is an important effecter of cellular behavior. Ultimately, chitosan-HDACS fiber scaffolds provided an adequate substrate for osteoblast attachment and proliferation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3026–3033, 2015.

Novel hydrogels and methods using same

Abstract: The present invention provides hydrogel-based compositions that are suitable for replacing or supplementing the nucleus pulposus in a subject. The compositions of the invention are useful for treating, ameliorating or reverting degradation of the nucleus pulposus in the subject. The present invention also provides methods of preparing and using such compositions.