Engineering Commons^™

Sensors For The Detection Of Ammonia As A Potential Biomarker For Health Screening, Peter P. Ricci, Otto J. Gregory

Chemical Engineering Faculty Publications

The presence of ammonia within the body has long been linked to complications stemming from the liver, kidneys, and stomach. These complications can be the result of serious conditions such as chronic kidney disease (CKD), peptic ulcers, and recently COVID-19. Limited liver and kidney function leads to increased blood urea nitrogen (BUN) within the body resulting in elevated levels of ammonia in the mouth, nose, and skin. Similarly, peptic ulcers, commonly from H. pylori, result in ammonia production from urea within the stomach. The presence of these biomarkers enables a potential screening protocol to be considered for frequent, non-invasive …

Free-Standing, Thin-Film Sensors For The Trace Detection Of Explosives, Peter P. Ricci, Otto J. Gregory

Chemical Engineering Faculty Publications

In a world focused on the development of cybersecurity, many densely populated areas and transportation hubs are still susceptible to terrorist attacks via improvised explosive devices (IEDs). These devices frequently employ a combination of peroxide based explosives as well as nitramines, nitrates, and nitroaromatics. Detection of these explosives can be challenging due to varying chemical composition and the extremely low vapor pressures exhibited by some explosive compounds. No electronic trace detection system currently exists that is capable of continuously monitoring both peroxide based explosives and certain nitrogen based explosives, or their precursors, in the vapor phase. Recently, we developed a …

Computational Study Of Helical And Helix-Hinge-Helix Conformations Of An Anti-Microbial Peptide In Solution By Molecular Dynamics And Vibrational Analysis, Faramarz Joodaki, Lenore M. Martin, Michael L. Greenfield

Chemical Engineering Faculty Publications

Many classical antimicrobial peptides adopt an amphipathic helical structure at a water-membrane interface. Prior studies led to the hypothesis that a hinge near the middle of a helical peptide plays an important role in facilitating peptide-membrane interactions.Here, dynamics and vibrations of a designed hybrid antimicrobial peptide LM7-2 in solution were simulated to investigate its hinge formation.Molecular dynamics simulation results on the basis of the CHARMM36 force field showed that the $\alpha$-helix LM7-2 bent around two or three residues near the middle of the peptide, stayed in a helix-hinge-helix conformation for a short period of time, and then returned to a …

In Situ Sers Detection Of Dissolved Nitrate On Hydrated Gold Substrates, Timo Küster, Geoffrey D. Bothun

Chemical Engineering Faculty Publications

The accurate and fast measurement of nitrate in seawater is important for monitoring and controlling water quality to prevent ecologic and economic disasters. In this work we show that the in situ detection of nitrate in aqueous solution is feasible at nanomolar concentrations through surface enhanced Raman spectroscopy (SERS) using native nanostructured gold substrates without surface functionalization. Spectra were analyzed as collected or after standard normal variate (SNV) normalization, which was shown through Principal Component Analysis (PCA) to reduce spectral variations between sample sets and improve Langmuir adsorption model fits. An additional normalization approach based on the substrate silicon template …

Carbon Nanotube–Liposome Complexes In Hydrogels For Controlled Drug Delivery Via Near-Infrared Laser Stimulation, S. Zahra M. Madani, Mohammad Moein Safaee, Mitchell Gravely, Carolynn Silva, Stephen Kennedy, Geoffrey D. Bothun, Daniel E. Roxbury

Chemical Engineering Faculty Publications

Externally controllable drug delivery systems are crucial for a variety of biological applications where the dosage and timing of drug delivery need to be adjusted based on disease diagnosis and progression. Here, we have developed an externally controllable drug delivery system by combining three extensively used platforms: hydrogels, liposomes, and single-walled carbon nanotubes (SWCNTs). We have developed carbon nanotube–liposome complexes (CLCs) and incorporated these structures into a 3D alginate hydrogel for use as an optically controlled drug delivery system. The CLC structures were characterized by using a variety of imaging and spectroscopic techniques, and an optimal SWCNT/lipid ratio was selected. …

The Response Of Synechococcus Sp. Pcc 7002 To Micro-/Nano Polyethylene Particles - Investigation Of A Key Anthropogenic Stressor, Mary C. Machado, Gina V. Vimbela, Tania T. Silva-Oliveira, Arijit Bose, Anubhav Tripathi

Chemical Engineering Faculty Publications

Microplastics or plastic particles less than 5 mm in size are a ubiquitous and damaging pol- lutant in the marine environment. However, the interactions between these plastic particles and marine microorganisms are just starting to be understood. The objective of this study was to measure the responses of a characteristic marine organism (Synechococcus sp. PCC 7002) to an anthropogenic stressor (polyethelene nanoparticles and microparticles) using molecular techniques. This investigation showed that polyethylene microparticles and nanoparticles have genetic, enzymatic and morphological effects on Synechococcus sp. PCC 7002. An RT-PCR analysis showed increases in the expression of esterase and hydro- lase genes …

Enhancement Of Macrophage Uptake Via Phosphatidylserine-Coated Acetalated Dextran Nanoparticles, Nishan K. Shah, Sweta K. Gupta, Zimeng Wang, Samantha A. Meenach

Chemical Engineering Faculty Publications

Although vital to the immune system, macrophages can act as reservoirs for pathogens such as tuberculosis and human immunodeficiency virus. Limitations in the treatment of such diseases include targeting therapeutics directly to macrophages and the large systemic dosages needed. The objective of this study is to develop a nanoparticle (NP)-based drug delivery system that can provide targeted delivery into macrophages. Acetalated dextran (Ac-Dex) NP loaded with the lipophilic model compound curcumin (CUR) were synthesized and coated in 1,2-dipalmitoyl-sn-glycero-3-phospho-l-serine (DPPS), a phospholipid that induces phagocytosis in macrophages. DPPS-CUR NP were found to release 67.8% of encapsulated CUR within 24 …

Ultrasonic Generation Of Pulsatile And Sequential Therapeutic Delivery Profiles From Calcium-Crosslinked Alginate Hydrogels, Tania Emi, Kendra Michaud, Emma Orton, Grace Santilli, Catherine Linh, Meaghan O'Connell, Fatima Issa, Stephen Kennedy

Chemical Engineering Faculty Publications

Control over of biological processes can potentially be therapeutically regulated through localized biomolecular deliveries. While implantable hydrogels can provide localized therapeutic deliveries, they do not traditionally provide the temporally complex therapeutic delivery profiles required to regulate complex biological processes. Ionically crosslinked alginate hydrogels have been shown to release encapsulated payloads in response to a remotely applied ultrasonic stimulus, thus potentially enabling more temporally complex therapeutic delivery profiles. However, thorough characterizations of how different types of therapeutic payloads are retained and ultrasonically released need to be performed. Additionally, the impact of potentially disruptive ultrasonic stimulations on hydrogel structure and temperature need …

Enhancing The Thermal Stability Of Carbon Nanomaterials With Dna, Mohammad Moein Safee, Mitchell Gravely, Adeline Lamothe, Megan Mcsweeney, Daniel E. Roxbury

Chemical Engineering Faculty Publications

Single-walled carbon nanotubes (SWCNTs) have recently been utilized as fillers that reduce the flammability and enhance the strength and thermal conductivity of material composites. Enhancing the thermal stability of SWCNTs is crucial when these materials are applied to high temperature applications. In many instances, SWCNTs are applied to composites with surface coatings that are toxic to living organisms. Alternatively, single-stranded DNA, a naturally occurring biological polymer, has recently been utilized to form singly-dispersed hybrids with SWCNTs as well as suppress their known toxicological effects. These hybrids have shown unrivaled stabilities in both aqueous suspension or as a dried material. Furthermore, …

Biomolecular Functionalization Of A Nanomaterial To Control Stability And Retention Within Live Cells, Mitchell Gravely, Mohammad Moein Safaee, Daniel E. Roxbury

Chemical Engineering Faculty Publications

Noncovalent hybrids of single-stranded DNA and single-walled carbon nanotubes (SWCNTs) have demonstrated applications in biomedical imaging and sensing due to their enhanced biocompatibility and photostable, environmentally responsive near-infrared (NIR) fluorescence. The fundamental properties of such DNA-SWCNTs have been studied to determine the correlative relationships between oligonucleotide sequence and length, SWCNT species, and the physical attributes of the resultant hybrids. However, intracellular environments introduce harsh conditions that can change the physical identities of the hybrid nanomaterials, thus altering their intrinsic optical properties. Here, through visible and NIR fluorescence imaging in addition to confocal Raman microscopy, we show that the oligonucleotide length …

Dna Sequence Mediates Apparent Length Distribution In Single-Walled Carbon Nanotubes, Mohammad Moein Safaee, Mitchell Gravely, Caroline Rocchio, Matthew Simmeth, Daniel E. Roxbury

Chemical Engineering Faculty Publications

Single-walled carbon nanotubes (SWCNTs) functionalized with short single-stranded DNA have been extensively studied within the last decade for biomedical applications due to the high dispersion efficiency and intrinsic biocompatibility of DNA as well as the photostable and tunable fluorescence of SWCNTs. Characterization of their physical properties, particularly their length distribution, is of great importance regarding their application as a bioengineered research tool and clinical diagnostic agent. Conventionally, atomic force microscopy (AFM) has been used to quantify the length of DNA-SWCNTs by depositing the hybrids onto an electrostatically charged flat surface. Here, we demonstrate that hybrids of DNA-SWCNTs with different oligomeric …

A Magnetically Responsive Biomaterial System For Flexibly Regulating The Duration Between Pro- And Anti-Inflammatory Cytokine Deliveries, Anita E. Tolouei, Nihan Dügler, Rosa Ghatee, Stephen Kennedy

Chemical Engineering Faculty Publications

While inflammation can be problematic, it is nonetheless necessary for proper tissue regeneration. However, it remains unclear how the magnitude and duration of the inflammatory response impacts regenerative outcome. This is partially due to the difficulty in temporally regulating macrophage phenotype at wound sites. Here, a magnetically responsive biomaterial system potentially capable of temporally regulating macrophage phenotypes through sequential, on‐demand cytokine deliveries is presented. This material system is designed to (i) rapidly recruit proinflammatory macrophages (M1) through initial cytokine deliveries and (ii) subsequently transition macrophages toward anti‐inflammatory phenotypes (M2s) through delayed, magnetically triggered cytokine release. Here, the ability of this …

A Carbon Nanotube Optical Reporter Maps Endolysosomal Lipid Flux, Jena V. Prakrit, Daniel E. Roxbury, Thomas V. Galassi, Leila Akkari, Christopher P. Horoszko, David B. Iaea, Januka Budhathoki-Uprety, Nina Pipalia, Abigail S. Haka, Jackson D. Harvey, Jeetain Mittal, Frederick R. Maxfield, Johanna A. Joyce, Daniel A. Heller

Chemical Engineering Faculty Publications

Lipid accumulation within the lumen of endolysosomal vesicles is observed in various pathologies including atherosclerosis, liver disease, neurological disorders, lysosomal storage disorders, and cancer. Current methods cannot measure lipid flux specifically within the lysosomal lumen of live cells. We developed an optical reporter, composed of a photoluminescent carbon nanotube of a single chirality, that responds to lipid accumulation via modulation of the nanotube’s optical band gap. The engineered nanomaterial, composed of short, single-stranded DNA and a single nanotube chirality, localizes exclusively to the lumen of endolysosomal organelles without adversely affecting cell viability or proliferation or organelle morphology, integrity, or function. …

Development And Physicochemical Characterization Of Acetalated Dextran Aerosol Particle Systems For Deep Lung Delivery, Zimeng Wang, Sweta K. Gupta, Samantha A. Meenach

Chemical Engineering Faculty Publications

Biocompatible, biodegradable polymers are commonly used as excipients to improve the drug delivery properties of aerosol formulations, in which acetalated dextran (Ac-Dex) exhibits promising potential as a polymer in various therapeutic applications. Despite this promise, there is no comprehensive study on the use of Ac-Dex as an excipient for dry powder aerosol formulations. In this study, we developed and characterized pulmonary drug delivery aerosol microparticle systems based on spray-dried Ac-Dex with capabilities of (1) delivering therapeutics to the deep lung, (2) targeting the particles to a desired location within the lungs, and (3) releasing the therapeutics in a controlled fashion. …

Fully Compositional Multi-Scale Reservoir Simulation Of Various Co2 Sequestration Mechanisms, Denis V. Voskov, Heath Henley, Angelo Lucia

Chemical Engineering Faculty Publications

A multi-scale reservoir simulation framework for large-scale, multiphase flow with mineral precipitation in CO₂-brine systems is proposed. The novel aspects of this reservoir modeling and simulation framework are centered around the seminal coupling of rigorous reactive transport with full compositional modeling and consist of (1) thermal, multi-phase flow tightly coupled to complex phase behavior, (2) the use of the Gibbs-Helmholtz Constrained (GHC) equation of state, (3) the presence of multiple homogeneous/heterogeneous chemical reactions, (4) the inclusion of mineral precipitation/dissolution, and (5) the presence of homogeneous/heterogeneous formations. The proposed modeling and simulation framework is implemented using the ADGPRS/GFLASH system. …

Dna–Carbon Nanotube Complexation Affinity And Photoluminescence Modulation Are Independent, Prakrit V. Jena, Mohammad M. Safaee, Daniel A. Heller, Daniel E. Roxbury

Chemical Engineering Faculty Publications

Short single-stranded DNA (ssDNA) has emerged as the natural polymer of choice for noncovalently functionalizing photoluminescent single-walled carbon nanotubes. In addition, specific empirically identified DNA sequences can be used to separate single species (chiralities) of nanotubes, with an exceptionally high purity. Currently, only limited general principles exist for designing DNA–nanotube hybrids amenable to separation processes, due in part to an incomplete understanding of the fundamental interactions between a DNA sequence and a specific nanotube structure, whereas even less is known in the design of nanotube-based sensors with determined optical properties. We therefore developed a combined experimental and analysis platform on …

Progress Toward Applications Of Carbon Nanotube Photoluminescence, Prakrit V. Jena, Thomas V. Galassi, Daniel E. Roxbury, Daniel A. Heller

Chemical Engineering Faculty Publications

In the fifteen years following the discovery of single-walled carbon nanotube (SWCNT) photoluminescence, investigators have made significant progress in their understanding of the phenomenon and toward the development of applications. The intrinsic potential of semiconducting carbon nanotubes – a family of bright, photostable near infrared (NIR) fluorophores (900–2100 nm) with tunable properties, has motivated their use as optical probes and sensors. In this perspective, we highlight the advances made in the synthesis, processing, modification, separation, and metrology of carbon nanotubes in the context of applications of their photoluminescence.

Single Nanotube Spectral Imaging To Determine Molar Concentrations Of Isolated Carbon Nanotube Species, Thomas V. Galassi, Prakrit V. Jena, Daniel E. Roxbury, Daniel A. Heller

Chemical Engineering Faculty Publications

Electronic and biological applications of carbon nanotubes can be highly dependent on the species (chirality) of nanotube, purity, and concentration. Existing bulk methods, such as absorbance spectroscopy, can quantify sp² carbon based on spectral bands, but nanotube length distribution, defects, and carbonaceous impurities can complicate quantification of individual particles. We present a general method to relate the optical density of a photoluminescent nanotube sample to the number of individual nanotubes. By acquiring 3-dimensional images of nanotubes embedded in a gel matrix with a reducing environment, we quantified all emissive nanotubes in a volume. Via spectral imaging, we assessed structural …

Synthesis And Characterization Of Nanocomposite Microparticles (Ncmp) For The Treatment Of Cystic Fibrosis-Related Infections, Zimeng Wang, Samantha A. Meenach

Chemical Engineering Faculty Publications

Purpose:

Pulmonary antibiotic delivery is recommended as maintenance therapy for cystic fibrosis (CF) patients who experience chronic infections. However, abnormally thick and sticky mucus present in the respiratory tract of CF patients impairs mucus penetration and limits the efficacy of inhaled antibiotics. To overcome the obstacles of pulmonary antibiotic delivery, we have developed nanocomposite microparticles (nCmP) for the inhalation application of antibiotics in the form of dry powder aerosols.

Methods:

Azithromycin-loaded and rapamycin-loaded polymeric nanoparticles (NP) were prepared via nanoprecipitation and nCmP were prepared by spray drying and the physicochemical characteristics were evaluated.

Results:

The nanoparticles were …

Development Of Three-Dimensional Lung Multicellular Spheroids In Air- And Liquid-Interface Culture For The Evaluation Of Anticancer Therapeutics, Samantha A. Meenach, Alexandran N. Tsoras, Ronald C. Mcgarry, Heidi M. Mansour, J. Zach Hilt, Kimberly W. Anderson

Chemical Engineering Faculty Publications

Three-dimensional (3D) lung multicellular spheroids (MCS) in liquid-covered culture (LCC) and air-interface culture (AIC) conditions have both been developed for the evaluation of aerosol anticancer therapeutics in solution and aerosols, respectively. The MCS were formed by seeding lung cancer cells on top of collagen where they formed spheroids due to the prevalence of cell-to-cell interactions. LCC MCS were exposed to paclitaxel (PTX) in media whereas AIC MCS were exposed to dry powder PEGylated phospholipid aerosol microparticles containing paclitaxel. The difference in viability for 2D versus 3D culture for both LCC and AIC was evaluated along with the effects of the …

On The Linear Approximation Of Mixture Internal Energies Of Departure, Robert B. Kelly, Angelo Lucia

Chemical Engineering Faculty Publications

Direct Monte Carlo simulation of internal energies of departure for binary mixtures of geological interest are gathered and compared to those calculated using a linear mixing rule. Simulation results for gas–oil, oil–oil, and oil–water mixtures show that the linear mixing rule used in the Gibbs–Helmholtz Constrained (GHC) equation of state framework gives accurate approximations of binary mixture internal energies of departure. A flowchart for computing internal energies of departure using Monte Carlo simulation is included along with a sensitivity analysis for the GHC mixture energy parameter with respect to uncertainty in internal energies of departure.

Synthesis Of Co-Electrospun Lead Selenide Nanostructures Within Anatase Titania Nanotubes For Advanced Photovoltaics, Evan K. Wujcik, Stephanie R. Aceto, David R. Heskett, Arijit Bose

Chemical Engineering Faculty Publications

Inorganic nano-scale heterostructures have many advantages over hybrid organic-inorganic dye-sensitized solar cells (DSSC or Grätzel cells), including their resistance to photo-bleaching, thermal stability, large specific surface areas, and general robustness. This study presents a first-of-its-kind low-cost all-inorganic lead selenide-anatase titania (PbSe/TiO₂) nanotube heterostructure material for photovoltaic applications. Herein, PbSe nanostructures have been co-electrospun within a hollow TiO2 nanotube with high connectivity for highly efficient charge carrier flow and electron-hole pair separation. This material has been characterized by transmission electron microscopy (TEM), electron diffraction, energy dispersive X-ray spectroscopy (EDX) to show the morphology and material composition of the synthesized …

Change In Chirality Of Semiconducting Single-Walled Carbon Nanotubes Can Overcome Anionic Surfactant Stabilisation: A Systematic Study Of Aggregation Kinetics, Iftheker A. Khan, Joseph R. V. Flora, A. R. M. Nabiul Afrooz, Nirupam Aich, P. Ariette Schierz, P. Lee Ferguson, Tara Sabo-Attwood, Navid B. Saleh

Chemical Engineering Faculty Publications

Single-walled carbon nanotubes’ (SWNT) effectiveness in applications is enhanced by debundling or stabilisation. Anionic surfactants are known to effectively stabilise SWNTs. However, the role of specific chirality on surfactant-stabilised SWNT aggregation has not been studied to date. The aggregation behaviour of chirally enriched (6,5) and (7,6) semiconducting SWNTs, functionalised with three anionic surfactants – sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and sodium deoxycholate – was evaluated with time-resolved dynamic light scattering. A wide range of mono- (NaCl) and divalent (CaCl₂) electrolytes as well as a 2.5 mg total organic carbon (TOC) L^–1 Suwannee River humic acid …

Switchable Release Of Entrapped Nanoparticles From Alginate Hydrogels, Cathal J. Kearney, Hadas Skaat, Stephen M. Kennedy, Jennifer Hu, Max Darnell, Theresa M. Raimondo, David J. Mooney

Chemical Engineering Faculty Publications

Natural biological processes are intricately controlled by the timing and spatial distribution of various cues. To mimic this precise level of control, the physical sizes of gold nanoparticles are utilized to sterically entrap them in hydrogel materials, where they are subsequently released only in response to ultrasound. These nanoparticles can transport bioactive factors to cells and direct cell behavior on‐demand.

Synthesis And Characterization Of Creka-Conjugated Iron Oxide Nanoparticles For Hyperthermia Applications, Anastasia M. Kruse, Samantha A. Meenach, Kimberly W. Anderson, J. Zach Hilt

Chemical Engineering Faculty Publications

One of the current challenges in the systemic delivery of nanoparticles in cancer therapy applications is the lack of effective tumor localization. Iron oxide nanoparticles coated with crosslinked dextran were functionalized with the tumor homing peptide CREKA, which binds to fibrinogen complexes in the extracellular matrix of tumors. This allows for the homing of these nanoparticles to tumor tissue. The iron oxide nanoparticle core allows for particle heating upon exposure to an alternating magnetic field (AMF) while the dextran coating stabilizes the particles in suspension and decreases the cytotoxicity of the system. Magnetically mediated hyperthermia (MMH) allows for the heating …

Low-Dose Chemotherapy Of Hepatocellular Carcinoma Through Triggered-Release From Bilayer-Decorated Magnetoliposomes, Yanjing Chen, Yuan Chen, Da Xiao, Arijit Bose, Ruitang Deng, Geoffrey D. Bothun

Chemical Engineering Faculty Publications

Low-dose (LD) chemotherapy is a promising treatment strategy that may be improved by controlled delivery. Polyethylene glycol-stabilized bilayer-decorated magnetoliposomes (dMLs) have been designed as a stimuli-responsive LD chemotherapy drug delivery system and tested in vitro using Huh-7 hepatocellular carcinoma cell line. The dMLs contained hydrophobic superparamagnetic iron oxide nanoparticles within the lipid bilayer and doxorubicin hydrochloride (DOX, 2 μM) within the aqueous core. Structural analysis by cryogenic transmission electron microscopy and dynamic light scattering showed that the assemblies were approximately 120 nm in diameter. Furthermore, the samples consisted of a mixture of dMLs and bare liposomes (no nanoparticles), which provided …

Metallic And Ceramic Thin Film Thermocouples For Gas Turbine Engines, Ian M. Tougas, Martin Amani, Otto J. Gregory

Chemical Engineering Faculty Publications

Temperatures of hot section components in today’s gas turbine engines reach as high as 1,500 °C, making in situ monitoring of the severe temperature gradients within the engine rather difficult. Therefore, there is a need to develop instrumentation (i.e., thermocouples and strain gauges) for these turbine engines that can survive these harsh environments. Refractory metal and ceramic thin film thermocouples are well suited for this task since they have excellent chemical and electrical stability at high temperatures in oxidizing atmospheres, they are compatible with thermal barrier coatings commonly employed in today’s engines, they have greater sensitivity than conventional …

Characterization And Aerosol Dispersion Performance Of Spray-Dried Chemotherapeutic Pegylated Phospholipid Particles For Dry Powder Inhalation Delivery In Lung Cancer, Samantha A. Meenach, Kimberly W. Anderson, J. Zach Hilt, Ronald J. Mcgarry, Heidi M. Mansour

Chemical Engineering Faculty Publications

Pulmonary inhalation chemotherapeutic drug delivery offers many advantages for lung cancer patients in comparison to conventional systemic chemotherapy. Inhalable particles are advantageous in their ability to deliver drug deep in the lung by utilizing optimally sized particles and higher local drug dose delivery. In this work, spray-dried and co-spray dried inhalable lung surfactant-mimic PEGylated lipopolymers as microparticulate/nanoparticulate dry powders containing paclitaxel were rationally designed via organic solution advanced spray drying (no water) in closed-mode from dilute concentration feed solution. Dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine poly(ethylene glycol) (DPPE-PEG) with varying PEG chain length were mixed with varying amounts of paclitaxel in methanol …

Thermoelectric Power Factor Of In2O3:Pd Nanocomposite Films., Otto J. Gregory, Matin Amani, Gustave C. Fralick

Chemical Engineering Faculty Publications

A nanocomposite exhibiting large thermoelectric powers and capable of operating at temperatures as high as 1100 °C in air was fabricated by embedding palladium nanoparticles into an indium oxide matrix via co-sputtering from metal and ceramic targets. Combinatorial chemistry techniques were used to systematically investigate the effect of palladium content in these nanocomposite films on thermoelectric response. Based on these rapid screening experiments, the thermoelectric properties of the most promising nanocomposites were evaluated as a function of post-deposition heat treatment at high temperatures. An n-type nanocomposite film was developed exhibiting a power factor of 4.5 x 10^-4 W/m·K^{2 …}

Hydration Repulsion Effects Of The Formation Of Supported Lipid Bylayers, Selver Ahmed, Rajesh Raman Madathingal, Stephanie L. Wunder, Yanjing Chen, Geoffrey D. Bothun

Chemical Engineering Faculty Publications

When zwitterionic lipids fuse onto substrates such as silica (SiO₂), the water of hydration between the two approaching surfaces must be removed, giving rise to an effective hydration repulsion. Removal of water around the polar headgroups of the lipid and the silanols (SiOH) of SiO₂ allows supported lipid bilayer (SLB) formation, although an interstitial water layer remains between the lipid and surface. The importance of hydration repulsion in SLB formation is demonstrated by monitoring fusion of zwitterionic lipids onto silica (SiO2) nanoparticles heat treated to control the silanol group (SiOH) density and thus the amount of bound …