Biomaterials and Nanoscience/Nanotechnology

Triggered Release via X-Radiation by Gold Embedded Magnetic Silica Nanotubes for Targeted Drug Delivery


Authors: Thao M. Nguyen, Sung Kyoung Kim, Gabriela Kramer-Marek, Jacek Capala* and Sang Bok Lee*
Department or Program: CHEM
Presented by: Thao Nguyen
Abstract: Current research efforts for triggered release in drug delivery have many flaws in protecting, delivery, and releasing the drugs in a therapeutic time frame. Here we suggest a new triggered release mechanism that releases drugs upon irradiation with X-ray. In order to control the releasing rate, silica nanotubes (SNTs) embedded with magnetic and gold nanoparticles (AuNPs) are utilized as the drug delivering vehicle. Drug molecules can be loaded on AuNPs using the template synthesis method. Modified surface sol gel method is used to synthesize the nanotubes with lengths of 500nm. Super paramagnetic iron oxide nanoparticles are embedded within the inner surface of the nanotubes providing magnetic properties for MRI imaging. Drug molecules are bound to AuNPs which contribute to the triggered release by X-ray irradiation, a mature technique in science for over a century. Preliminary data indicate the nanotubes showing great performance in triggered release using dye molecules by X-ray irradiation. Future goals of the research involve tumor targeting with Affibody™ molecules and radionuclide imaging using PET.

Heterogeneous Nanostructure Design for Electrochemical Energy Storage Devices


Authors: Stefanie Sherrill, Zhe Gui, Jonathon Duay, Ran Liu, Parag Banerjee, Gary W. Rubloff, Sang Bok Lee
Department or Program: CHEM
Presented by: Stefanie Sherrill
Abstract: Current research efforts in energy involve the development of next-generation electrical energy storage systems. As the demand for electrical energy storage devices grows, there is an urgent need to fully understand and overcome the scientific challenges involved. These fundamental challenges involve the basics of thermodynamic and kinetic limits of materials. Three main issues are currently being investigated in order to provide solutions to these challenges: electrical conductivity, charge transport rate, and mechanical stability. These issues are directly related to the design and selection of materials used in the device. Here we investigate a manganese oxide/titanium nitride (MnO2/TiN) heterogeneous nanostructure design in anodic aluminum oxide (AAO) for the development of an electrical energy storage device that results in dramatic improvements in energy and power density. The highly ordered AAO structure significantly enhances the capability of electrical energy storage devices due to its characteristic advantages such as high surface area, cost-effective fabrication, and flexible control of dimensions. The high electrical conductivity and mechanical stability of TiN and favorable properties of MnO2 (high energy density, inexpensive, abundant, nontoxic, environmentally friendly) merge into AAO to form a more efficient energy system. The heterogeneous nanostructure improves upon current limitations in electrical energy storage devices such as ion transport rate, conductivity (charge/discharge rate), and mechanical stability.

Virus-Enabled Silicon Anode for Lithium-ion batteries


Authors: Xilin Chen, Konstantinos Gerasopoulos, Juchen Guo, Adam Brown, Chunsheng Wang, Reza Ghodssi, James N. Culver
Department or Program: ENCH
Presented by: Xilin Chen
Abstract: A novel three-dimensional Tobacco mosaic virus (TMV) assembled Silicon anode is reported. This electrode combines genetically modified virus templates for the production of high aspect ratio nano-featured surfaces with electroless deposition to produce an integrated nickel current collector followed by sputter coatings of silicon to obtain a high capacity surface. Assembly of this composite silicon anode into a lithium ion battery format produced high capacities (3300mAh/g), excellent charge-discharge cycling stability (0.20% loss per cycle at 1C), and consistent rate capabilities (46.4% at 4C) between 1.5 and 0 V. After lithium insertion and extraction, a novel sponge-like structure consisting of a fibrous-like silicon matrix is found. These findings demonstrate the use of a biological template to produce a unique nano-composite electrode architecture that displays a nearly 10-fold increase in capacity over currently available graphite anodes with remarkable cycling stability.

Characterization of Biological Nanoparticles and Proteins using Electrospray – Differential Mobility Analyzer (ES-DMA)


Authors: S. Guha, D-H Tsai, L. F. Pease III, R. A. Zangmeister, K. Brorson, M. J. Tarlov, and M. R. Zachariah
Department or Program: ENME
Presented by: Suvajyoti Guha
Abstract: We demonstrate our studies of Electrospray- Differential Mobility analysis (ES-DMA) of nanoparticle (NP) systems, which more specifically includes traditional inorganic NP’s, as well as protein aggregates, and viruses. We use the ES-DMA to monitor the temporal disintegration of PR772 and the appearance of degradation products, essential to viral stability assays. We also demonstrate the capability of studying NP-antibody, virus-antibody and NP-virus binding which can help determine surface coverage and type of interactions if studied systematically. We also use the ES-DMA to study protein aggregation. Size distributions of IgG species ranging from monomers to pentamers, are obtained and are found to correlate with those calculated from simple models, which take the structural dimensions of IgG from protein crystallographic data. The dependence of IgG aggregation on the solution concentration, pH, and ionic strength are also examined, and the portion of aggregates of crosslinked antibodies quantified.

Zein Self Assemble Structures Self-Affected by pH, Surfactants, and Solvent Type


Authors: Boce Zhang, Qin Wang
Department or Program: NFSC
Presented by: Boce Zhang
Abstract: JUSTIFICATION: Encapsulation of bioactive compounds is of interest to the food industry. Zein is an excellent film former and has been used for oil encapsulation. Preliminary research showed that zein forms self-assembled nanoscale structures that might be used as carriers to encapsulate bioactive compounds and improve their bioavailability. OBJECTIVE: The objective of this study is to investigate the effect of pH and zein purity on the morphology of zein self-assembled structures. The effect of two surfactants was also investigated for their ability to alter zein morphology. METHODS: Two commercially available zein samples (low carotenoid content [LCC], high carotenoid content [HCC], 1mg/ml) were dissolved separately in 75% ethanol/water solution at different pH levels. pH of zein solutions was adjusted by HCl Solution (pH=2.0), chloroacetic acid solution (pH=3.6), and NaOH solution (pH=12.0). Zein solution as it is, pH~6.0, was used as control for comparison. Two surfactants, oleic acid (OA) and oleylamine (OL), were added separately to zein solutions prepared above. Both of them have similar lipophilic tails, however, carrying opposite charge on their polar heads. After zein-surfactant solutions were well mixed, they were dripped onto aluminum weighing pan, carefully spread, and dried in hood at ambient temperature. The surface micro and nano structures of zein deposits were characterized by focused ion beam/scanning electron microscopy (FIB/SEM). RESULTS: The pH level of the zein system significantly determines the morphology of zein structure. At pH=2, zein formed films regardless of the presence of surfactants, while zein formed particles at pH=12. In basic solutions, the surfactants had minor influence on the zein morphology resulting in distorted zein spheres. Exception is for the HCC zein sample with OA, uneven films formed instead. The effect of OA on zein morphology seems to be significant at all pH levels, however, the effect of OL is trivial. In HCl solution, zein formed even and rough films when OA and OL were added, respectively. In NaOH solution, OA disrupted zein spheres and fused them to form a film. OL converted zein nano-particles to big clusters. In ClCH2COOH condition, zein formed a semiembedded spherical structure when OL was added comparing to the sponge-like structure reported previously with OA. The changing morphology of zein may be explained by the effect of non-covalent bonding (hydrogen bond and hydrophobic force) between zein and additives. The purity of zein also plays an important role for different zein morphology formation. HCC zein tends to form film at all pH levels, perhaps with help of lipid impurities. LCC, however, preserves spherical shape of zein, especially at base solutions. SIGNIFICANCE: The formation of nano-particles may lead to some novel properties and applications of zein. Applications may include encapsulation of bioactive compounds and construction of tissue scaffolds.

Properties and Stability of SDBS-rich Surfactant Vesicle Systems for Drug Delivery Applications


Authors: Lenea H. Rader, Juhee Park, Glen B. Thomas, Douglas S. English, and Philip DeShong*
Department or Program: CHEM
Presented by: Lenea Rader
Abstract: Here we report the formation of anionic vesicles composed of the surfactants cetyltrimethylammonium tosylate (CTAT) and sodium dodecylbenzene sulfonate (SDBS) for use as potential drug delivery applications over conventional liposomes. Surfactant vesicles were prepared using a variety of methods in order to optimize vesicles for large-scale production. Colloidal solutions are stable for over six months, form vesicles of approximately 110 nm in diameter, and have a membrane surface charge similar to the charge found on human cells, ζ = -56 mV. Vesicles were functionalized and characterized with glycoconjugates (glucose, maltose, maltotriose), peptides (PADRE), nonionic surfactants (lutein), and dyes (rhodamine 6G). Lectin binding studies with concanavalin A confirm that glycoconjugates are intact on the vesicle surface thus showing potential for these systems for use as targeted delivery vehicles.

MSN as Controlled Release Devices


Authors: Matthew T. Hurley, Peter DeMuth, Chunwei Wu, Stephanie Galanie, Sara Lioi, Michael Zachariah and Philip DeShong
Department or Program: CHEM
Presented by: Matthew Hurley
Abstract: Mesoporous silica nanoparicles (MSN) have potential as drug delivery and/or controlled release devices due to their high surface area and absorption capabilities. The effect of surface charge and pH on the release of guest molecules from MSN has been studied. Release profiles of rhodamine 6G from bare and amine-coated MSN at pH 5.0 and 7.4 demonstrate that electrostatic interactions between entrapped and/or surface bound rhodamine 6G molecules and the charged surface of the MSN have a significant effect on release kinetics. Release of rhodamine 6G from amine-coated MSN can be fit to a single exponential function, while release from bare MSN can be fit to a double exponential function. These results and the interpretation of these results will be discussed in detail.

Microfludic Generation, Manipulation and Assembly of Superparamagnetic Microcapsules on a Thermoplastic PMMA chip device


Authors: Kunqiang Jiang, Srinivasa R. Raghavan, and Don L. DeVoe
Department or Program: CHEM
Presented by: Kunqiang Jiang
Abstract: Microfluidic method offers superior advantages for precise production of monodisperse polymeric capsules with unprecedented control over their sizes, geometries, as well as biochemical and mechanical properties. Here we report the generation, magnetic functionization and covalent linkage of chitosan microcapsules on a developed PMMA microfluidic platform. A superparamagnetic solution is prepared first by mixing γ-Fe2O3 nanoparticles into aqueous chitosan solution (dispersed phase), which is passively sheared off thereafter via the T junction by a continuous phase of hexadecane/Span 80 to form highly monodisperse chitosan droplets. These precursor droplets are then crosslinked interfacially by a downstream flow of a dialdehyde reagent, glutaraldehyde, through robust amine-aldehyde bonding. We have demonstrated facile and fine control over capsule sizes, configurations and geometries via simply adjusting the flow rate ratio and incubation time. In addition, a novel concept of linear capsule assembly has been proven through realizing covalent interconnecting bridge among adjacent capsules, and magneto-mechanical positioning and manipulation are achieved further upon application of an external magnetic field. This microfluidic generating and linking approach has promising potentials in various fields ranging from design for cargo carriers of biological active species, fabrication of spatial biopolymeric supporting matrices, to production of miniaturized artificial microrobots.

Synthesis and characterization of RuO2/poly (3,4-ethylenedioxythiophene) (PEDOT) composite nanotubes for supercapacitors


Authors: Ran Liu, Zhe Gui, Jonathon Duay,Stefanie Sherrill, Sang Bok Lee
Department or Program: CHEM
Presented by: Zhe Gui
Abstract: Heterogeneous materials of nanostructures have drawn an intensive attention due to their capability as electrode materials for high-power supercapacitor. In this work, we synthesized RuO2/PEDOT composite nanotubes by using a step-wise template method, during which alumina template was first use to direct the growth of PEDOT, and then PEDOT nanotubes served as template for the growth of RuO2. By the deposition of RuO2 into the porous network of the PEDOT nanobtubes, we got dramatically improved specific capacitance with the value of 640 F/g, compared to 150 F/g without the addition of RuO2. The power density, benefited from the low ionic resistance and short diffusion path of thin-walled composite nanotubes, was maintained as high as 20 kW/kg. Microscopic characterizations reveal that the combination of the brittle RuO2 and the flexible PEDOT materials also prevents the nanotubes from significant collapsing and breaking. This study could pave the way for the research on other types of composite materials for electrochemical energy storage.