No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Spinneret based Tunable Engineered Parameters (STEP) Platform is a recently reported pseudo-dry spinning and non-electrospinning technique that allows for the deposition of aligned polymeric nano-fibers with control on fiber diameters and orientation in single and multiple layers (diameter: sub 100nm micron, length: mm-cm), deposition (parallelism 2.5 degrees) and spacing (microns)). A wide range of polymers such as PLGA, PLA, PS, and PU have been utilized for their unique material properties in scaffold design. In this thesis two unique bioscaffolds are demonstrated for the measurement of group cell migration for wound closure and single cell contractility force for the study of force modulation. The wound healing assay bridges the gap between confluent reservoirs of NIH3T3 fibroblasts through arrangement of a suspended array of fibers guiding group cell migration along the fiber axis. This platform demonstrates that topographical and geometrical features of suspended fibers play a very important role in wound closure. Spacing, alignment and orientation were optimized to shown an increased rate of closure. In the second complementary assay, we report a fused-fiber network of suspended fibers capable of measuring single cell forces. Results from our experiments demonstrate that force behavior is dependent on mechanical properties such as stiffness and geometry of fiber networks. We also demonstrate changes in spatial and temporal organization of focal adhesion zyxin in response to single cell migration on these networks. / Master of Science

Yes / This study investigated adsorption kinetics, adsorption equilibrium, and adsorption isotherm of three dyes [i.e., methylene blue (MB), rhodamine-B (RB), and safranin T (ST)] onto polyacrylonitrile (PAN) and ethanolamine (EA) grafted PAN nanofibers (NFs) membranes (EA-g-PAN). The membranes were characterized by field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR) spectroscopy, and Brunauer–Emmet–Teller (BET). FE-SEM showed a smooth morphology for the NFs before and after grafting, while FT-IR confirmed EA grafting into the nitrile group of PAN. The grafting percentage with no change in the physical nature of the membrane was 12.18%. The nitrogen adsorption–desorption isotherms for PAN and EA-g-PAN NFs membranes were similar and classified as a Type IV according to the International Union of Pure and Applied Chemistry. The surface area, pore-volume, and pore size of the EA-g-PAN increased to 21.36 m2 g−1, 0.16 cm3 g−1, and 304.93 Å, respectively. The pores were cylindrical mesopores with bimodal openings, which means that pores were open at both ends. The adsorption of the MB, RB, and ST dyes onto the PAN and EA-g-PAN NFs membranes leveled off at ~ 60 min. The adsorption kinetics showed good fitting to pseudo-second-order kinetic model and multi-step diffusion process. The order of the dye adsorption was PAN / the Deanship of Scientific Research, King Saud University [RG-1440-060]

Yes / The development of high-performance flexible pressure-sensing materials necessitates the simultaneous achievement of exceptional flexibility, conductivity, and alignment of micro-nano structures with the mechanical response characteristics inherent to these materials. In this study, we propose a novel method for preparing flexible microneedles as a pressure-sensitive sensor array. Firstly, we obtain conductive composite particles through extrusion granulation, which consists of a compact conductive network with micron-scale filler as the skeleton and nano-filler filling in the gaps within the network. Moreover, by utilizing the ‘volume exclusion’ effect of the microneedle array on the micron-scale filler during injection molding, nanofillers dominate in entering the microneedle. As a result, our molded product exhibits high flexibility and moderate conductivity in its pressure-sensitive area, thereby providing ultra-high-pressure resistance along with desired response characteristics and sensitivity for sensors. Additionally, due to synergistic effects between microscale fillers and nano-fillers in non-pressure sensitive bases, a compact conductive network is formed that imparts sufficient conductivity to sensor materials. The method yields sensors with excellent repeatability, high dimensional accuracy, and good consistency, effectively addressing core application challenges of flexible sensors. The microstructure array flexible sensor fabricated using high-precision injection molding technology offers high efficiency, low cost, and scalability for mass production. Furthermore, the sensitivity of sensors produced by this method is significantly higher—26.6% greater than those made using traditional methods—with a sensitivity as high as 4.71kPa -1 .