College of Science and Engineering
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Browsing College of Science and Engineering by Department "Materials Science, Engineering, and Commercialization"
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Item Conductive Polymer-based Nanoparticles for Laser-mediated Photothermal Ablation of Cancer: Synthesis, Characterization, and in vitro Evaluation(Dove Press, 2017-01) Cantu, Travis; Walsh, Kyle; Pattani, Varun P.; Moy, Austin J.; Tunnell, James; Irvin, Jennifer A.; Betancourt, TaniaLaser-mediated photothermal ablation of cancer cells aided by photothermal agents is a promising strategy for localized, externally controlled cancer treatment. We report the synthesis, characterization, and in vitro evaluation of conductive polymeric nanoparticles (CPNPs) of poly(diethyl-4,4'-{[2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-1,4-phenylene] bis(oxy)}dibutanoate) (P1) and poly(3,4-ethylenedioxythiophene) (PEDOT) stabilized with 4-dodecylbenzenesulfonic acid and poly(4-styrenesulfonic acid-co-maleic acid) as photothermal ablation agents. The nanoparticles were prepared by oxidative-emulsion polymerization, yielding stable aqueous suspensions of spherical particles of <100 nm diameter as determined by dynamic light scattering and electron microscopy. Both types of nanoparticles show strong absorption of light in the near infrared region, with absorption peaks at 780 nm for P1 and 750 nm for PEDOT, as well as high photothermal conversion efficiencies (~50%), that is higher than commercially available gold-based photothermal ablation agents. The nanoparticles show significant photostability as determined by their ability to achieve consistent temperatures and to maintain their morphology upon repeated cycles of laser irradiation. In vitro studies in MDA-MB-231 breast cancer cells demonstrate the cytocompatibility of the CPNPs and their ability to mediate complete cancer cell ablation upon irradiation with an 808-nm laser, thereby establishing the potential of these systems as agents for laser-induced photothermal therapy.Item Droplet Impinging Behavior on Surfaces with Wettability Contrasts(Elsevier, 2018-08) Farshchian, Bahador; Pierce, Jacoby; Beheshti, Mohammad S.; Park, Sunggook; Kim, NamwonHeterogeneous substrates with moderate and extreme wettability contrasts were fabricated by comprising of superhydrophobic/hydrophilic and superhydrophobic/extremely hydrophilic surfaces, respectively. The interactions of water droplets impinging on the surfaces with sharp wettability contrasts were investigated experimentally. The impinging droplets that slightly touch the hydrophilic or extremely hydrophilic areas on each substrate exhibit a directional rebounding towards the more wetting surfaces, i.e., hydrophilic or extremely hydrophilic surface. The trajectory and landing distance of the rebounded droplets were tailored by controlling the releasing height of the droplet, wetting contrast across the border, and portion of the droplet touching the more wetting surface of the substrates with wettability contrasts. The landing distance of the droplet increases with the increased releasing height and higher wettability contrast across the border. Increasing the portion of the impinging droplet touching the more wetting surface of the heterogeneous substrates leads to the shorter landing distance of rebounded droplets.Item Electroactive Polymer Nanoparticles Exhibiting Photothermal Properties(Journal of Visualized Experiments, 2016-01) Cantu, Travis; Rodier, Bradley; Iszard, Zachary; Kilian, Alissa; Pattani, Varun P.; Walsh, Kyle; Weber, Katharina; Tunnell, James; Betancourt, Tania; Irvin, Jennifer A.A method for the synthesis of electroactive polymers is demonstrated, starting with the synthesis of extended conjugation monomers using a three-step process that finishes with Negishi coupling. Negishi coupling is a cross-coupling process in which a chemical precursor is first lithiated, followed by transmetallation with ZnCl2. The resultant organozinc compound can be coupled to a dibrominated aromatic precursor to give the conjugated monomer. Polymer films can be prepared via electropolymerization of the monomer and characterized using cyclic voltammetry and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. Nanoparticles (NPs) are prepared via emulsion polymerization of the monomer using a two-surfactant system to yield an aqueous dispersion of the polymer NPs. The NPs are characterized using dynamic light scattering, electron microscopy, and UV-Vis-NIR-spectroscopy. Cytocompatibility of NPs is investigated using the cell viability assay. Finally, the NP suspensions are irradiated with a NIR laser to determine their effectiveness as potential materials for photothermal therapy (PTT).Item High Permeability Photosintered Strontium Ferrite Flexible Thin Films(Multidisciplinary Digital Publishing Institute, 2021-01-01) Ahmad, Abid; Mishra, Bhagyashree; Foley, Andrew; Wood, Leslie; Chen, Maggie YihongThe paper is focused on the development and optimization of strontium ferrite nanomaterial and photosintered flexible thin films. These magnetic thin films are characterized with direct current (DC) and high frequency measurements. For photosintered strontium ferrite samples, we achieved relative complex permeability of about 29.5-j1.8 and relative complex permittivity of about 12.9-j0.3 at a frequency of 5.9 GHz.Item High Throughput Preparation of Poly(Lactic-Co-Glycolic Acid) Nanoparticles Using Fiber Fluidic Reactor(Multidisciplinary Digital Publishing Institute, 2020-07-09) Aghda, Niloofar Heshmati; Lara, Emilio; Patel, Pulinkumar; Betancourt, TaniaPolymeric nanoparticles (NPs) have a variety of biomedical, biotechnology, agricultural and environmental applications. As such, a great need has risen for the fabrication of these NPs in large scales. In this study, we used a high throughput fiber reactor for the preparation of poly(lactic-co-glycolic acid) (PLGA) NPs via nanoprecipitation. The fiber reactor provided a high surface area for the controlled interaction of an organic phase containing the PLGA solution with an aqueous phase, containing poly(vinyl alcohol) (PVA) as a stabilizer. This interaction led to the self-assembly of the polymer into the form of NPs. We studied operational parameters to identify the factors that have the greatest influence on the properties of the resulting PLGA NPs. We found that the concentration of the PLGA solution is the factor that has the greatest effect on NP size, polydispersity index (PDI), and production rate. Increasing PLGA concentration increased NP sizes significantly, while at the same time decreasing the PDI value. The second factor that was found to affect NP properties was the concentration of PVA solution, which resulted in increased NP sizes and decreased production rates. Flowrates of the feed streams also affected NP size to a lesser extent, while changing the operational temperature did not change the product’s features. In general, the results demonstrate that fiber reactors are a suitable method for the large-scale, continuous preparation of polymeric NPs suitable for biomedical applications.Item Inkjet-Printed Graphene-Based 1 × 2 Phased Array Antenna(Multidisciplinary Digital Publishing Institute, 2020-09-18) Monne, Mahmuda Akter; Grubb, Peter; Stern, Harold; Subbaraman, Harish; Chen, Ray T.; Chen, Maggie YihongLow-cost and conformal phased array antennas (PAAs) on flexible substrates are of particular interest in many applications. The major deterrents to developing flexible PAA systems are the difficulty in integrating antenna and electronics circuits on the flexible surface, as well as the bendability and oxidation rate of radiating elements and electronics circuits. In this research, graphene ink was developed from graphene flakes and used to inkjet print the radiating element and the active channel of field effect transistors (FETs). Bending and oxidation tests were carried out to validate the application of printed flexible graphene thin films in flexible electronics. An inkjet-printed graphene-based 1 × 2 element phased array antenna was designed and fabricated. Graphene-based field effect transistors were used as switches in the true-time delay line of the phased array antenna. The graphene phased array antenna was 100% inkjet printed on top of a 5 mil flexible Kapton® substrate, at room temperature. Four possible azimuth steering angles were designed for −26.7°, 0°, 13°, and 42.4°. Measured far-field patterns show good agreement with simulation results.Item Low temperature atomic layer deposition of zirconium oxide for inkjet printed transistor applications(Royal Society of Chemistry, 2019-01) Jewel, Mohi Uddin; Mahmud, MD Shamim; Monne, Mahmuda Akter; Zakhidov, Alex; Chen, Maggie YihongWe report the growth of zirconium oxide (ZrO2) as a high-k gate dielectric for an inkjet-printed transistor using a low-temperature atomic layer deposition (ALD) from tetrakis(dimethylamido)zirconium (TDMAZr) and water precursors. All the samples are deposited at low-temperature ranges of 150–250 °C. The films are very uniform with RMS roughness less than 4% with respect to their thickness. The atomic force microscopy (AFM) shows a significant change in surface morphology from tapered posts to undulating mountain-like structures with several hundreds of ALD cycles. The results from X-ray diffraction (XRD) analysis exhibit an amorphous to the crystalline structure with temperature variation, which is independent of the thickness of the films. All our samples are hydrophilic as contact angles are less than 90°. The capacitance–voltage (C–V) and conductance–voltage (Gp/ω–V) characteristics of ZrO2 dielectrics for silicon metal–oxide–semiconductor (MOS) capacitors are studied for different temperatures. For the n-type substrate MOS capacitors, the dielectric constants are estimated to be 7.5–11. Due to the low deposition temperature, a hydrophilic surface, and high k value, the ALD-ZrO2 dielectric can be compatible for printed transistors. The processes of fabrication and characterization of inkjet-printed graphene transistors is demonstrated using the ZrO2 dielectric. The possible solvents, surfactant, and the dielectric induced modifications in graphene flakes are demonstrated by Raman spectra. The graphene flakes spread uniformly on the ZrO2 surface. The functional inkjet-printed graphene transistor characteristics are demonstrated to illustrate the field effect behavior with the ALD-ZrO2 dielectric.Item Material selection and fabrication processes for flexible conformal antennas(Hindawi, 2018-05) Monne, Mahmuda Akter; Lan, Xing; Chen, Maggie YihongFlexible antennas offer many advantages for communication, radar, RF identification, and energy harvesting applications. A review on the material selection and fabrication process of flexible antennas is presented since these aspects are critical to the antenna’s overall electrical and mechanical performance. A number of different material and fabrication techniques are reviewed in detail for different types of antennas. In addition, experimental results are also discussed for these antennas, which further underlines the importance of material selection and the various fabrication processes.Item Synthesis of Printable Polyvinyl Alcohol for Aerosol Jet and Inkjet Printing Technology(Multidisciplinary Digital Publishing Institute, 2021-02-22) Monne, Mahmuda Akter; Howlader, Chandan Qumar; Mishra, Bhagyashree; Chen, Maggie YihongPolyvinyl Alcohol (PVA) is a promising polymer due to its high solubility with water, availability in low molecular weight, having short polymer chain, and cost-effectiveness in processing. Printed technology is gaining popularity to utilize processible solution materials at low/room temperature. This work demonstrates the synthesis of PVA solution for 2.5% w/w, 4.5% w/w, 6.5% w/w, 8.5% w/w and 10.5% w/w aqueous solution was formulated. Then the properties of the ink, such as viscosity, contact angle, surface tension, and printability by inkjet and aerosol jet printing, were investigated. The wettability of the ink was investigated on flexible (Kapton) and non-flexible (Silicon) substrates. Both were identified as suitable substrates for all concentrations of PVA. Additionally, we have shown aerosol jet printing (AJP) and inkjet printing (IJP) can produce multi-layer PVA structures. Finally, we have demonstrated the use of PVA as sacrificial material for micro-electro-mechanical-system (MEMS) device fabrication. The dielectric constant of printed PVA is 168 at 100 kHz, which shows an excellent candidate material for printed or traditional transistor fabrication.Item Targeting Hepatocellular Carcinoma with Aptamer-functionalized PLGA/PLA-PEG Nanoparticles(Society of Photo-optical Instrumentation Engineers, 2014-08-27) Weigum, Shannon E.; Sutton, Melissa; Barnes, Eugenia; Miller, Sarah; Betancourt, TaniaHepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide, particularly in regions where chronic Hepatitis B and C infections are common. Nanoparticle assemblies that incorporate high-affinity aptamers which specifically bind malignant hepatocellular carcinoma cells could be useful for targeted drug delivery or enhancing contrast with existing ablation therapies. The in vitro interactions of a tumor-specific aptamer, TLS11a, were characterized in a hepatoma cell line via live-cell fluorescence imaging, SDS-PAGE and Western Blotting techniques. Cell surface binding of the aptamer-AlexaFluor® 546 conjugate was found to occur within 20 minutes of initial exposure, followed by internalization and localization to late endosomes or lysosomes using a pH-sensitive LysoSensor™ Green dye and confocal microscopy. Aptamer-functionalized polymer nanoparticles containing poly(lactic-co-glycolic acid) (PLGA) and poly(lactide)-b-poly(ethylene glycol) (PLA-PEG) were then prepared by nanoprecipitation and passively loaded with the chemotherapeutic agent, doxorubicin, yielding spherical nanoparticles approximately 50 nm in diameter. Targeted drug delivery and cytotoxicity was assessed using live/dead fluorescent dyes and a MTT colorimetric viability assay with elevated levels of cell death found in cultures treated with either the aptamer-coated and uncoated polymer nanoparticles. Identification and characterization of the cell surface protein epitope(s) recognized by the TLS11a aptamer are ongoing along with nanoparticle optimization, but these preliminary studies support continued investigation of this aptamer and functionalized nanoparticle conjugates for targeted labeling and drug delivery within malignant hepatocellular carcinomas.Item Wormlike Micellar Solutions, Beyond the Chemical Enhanced Oil Recovery Restrictions(Multidisciplinary Digital Publishing Institute, 2019-09) Nodoushan, Emad Jafari; Yi, Taeil; Lee, Young Ju; Kim, NamwonWhile traditional oil recovery methods are limited in terms of meeting the overall oil demands, enhanced oil recovery (EOR) techniques are being continually developed to provide a principal portion of our energy demands. Chemical EOR (cEOR) is one of the EOR techniques that shows an efficient oil recovery factor in a number of oilfields with low salinity and temperature ranges. However, the application of cEOR under the harsh conditions of reservoirs where most of today’s crude oils come from remains a challenge. High temperatures, the presence of ions, divalent ions, and heterogeneous rock structures in such reservoirs restrict the application of cEOR. Polymer solutions, surfactants, alkaline-based solutions, and complex multi-components of them are common chemical displacing fluids that failed to show successful recovery results in hostile conditions for various reasons. Wormlike micellar solutions (WMS) are viscoelastic surfactants that possess advantageous characteristics for overcoming current cEOR challenges. In this study, we first review the major approaches and challenges of commonly used chemical agents for cEOR applications. Subsequently, we review special characteristics of WMS that make them promising materials for the future of cEOR.