Research Experience for Undergraduates

Project Examples

BRIEF DESCRIPTION OF INDEPENDENT PROJECTS

ANDERSON
Our interests are in the area of biointerfaces as it relates to the interaction of synthetic materials with biological cells and proteins.

Design of Biocompatible Materials: Blood-contacting devices are becoming more common and, while many of these devices have been successfully used for many years and are judged to be therapeutically 6 beneficial, their performance is less than optimal. Almost immediately upon implantation in the body, blood-contacting materials become completely coated with proteins and this leads to attachment of cells. Aggregated platelets combine with protein on the surface and lead to formation of thrombi, which can cause significant problems downstream and also hinder the performance of the device. Bacteria, such as Treponema pallidum can go unnoticed by the body and survive in a latent form for several years through a process known as antigenic disguise. The overall objective of this research is to use antigenic disguise to create biocompatible surfaces. It has been shown that Treponema pallidum binds soluble dimeric fibronectin, and some investigators believe that the bound fibronectin serves as an antigenic disguise for the bacterium. Recently, the protein responsible for binding soluble fibronectin, Tp0483, has been identified, expressed and purified. In this proposed study, proteins such as, Tp0483 will be adsorbed to surfaces using self-assembled monolayers (SAM), and the adsorption of plasma proteins such as fibronectin will be investigated using surface plasmon resonance spectroscopy. In addition, the mechanism of adsorption of plasma proteins to the antigenic disguised protein will be studied using atomic force microscopy. The REU student will learn protein expression and purification techniques along with techniques used to create self-assembled monolayers. He/she will also be directly involved in collecting experimental data using surface plasmon resonance and atomic force microscopy.

BACHAS
The main thrust of our research lies in the area of Bioanalytical Chemistry. Specifically, we are interested in the development of new polymer membrane-based sensors for detecting biochemically important molecules and ions.

Electrochemically Imprinted Membranes for Sensors: Sensing membranes will be prepared by an electrochemically mediated imprinting process. Specifically, by electrochemically polymerizing monomers with appropriate functional groups in the presence of an electrolyte, new material can be obtained with a pore architecture that is complimentary to the structure of a "print" ion or molecule in solution. These materials will be used as ion-selective membranes in the development of sensors with unique selectivities. Further, by using monomers containing a catalytic unit, it should be possible to design catalytic membranes with enhanced selectivity. The REU student will be involved in the synthesis of corrin derivatives with polymerizable units, their electrochemical polymerization, their characterization using a variety of electrochemical methods, and their application in sensing and/or catalysis.

BHATTACHARYYA
The focus of our research group is in the area of functionalized membranes and nanostructured materials.

Functionalized membranes for selective separations and r eactions: Conventional membranes (such reverse osmosis and ultrafiltration) lack selectivity and high flux at low pressures. The synthesis of tunable (singe layer and multi-layer assembly in pores) membranes provide added opportunities in permeate flux and separation selectivity control. The attachment of selected types of polyelectrolytes and the in-situ synthesis of nanoparticles in membranes allows highly effective separations at low pressures and toxic organic destruction at room temperature. The REU student will use the layer-by-layer (LBL) assembly technique, most commonly conducted by intercalation of positive and negative polyelectrolytes, to assemble supramolecular structures and develop nanostructured materials. Non-stoichiometric immobilization of charged polyelectrolyte assemblies within confined pore geometries leads to an enhanced volume density of ionizable groups in the membrane phase. This increase in the effective charge density allows for Donnan or charge-based exclusion of ionic species using porous materials characterized by hydraulic permeability values well beyond conventional membrane processes. The project will also include chelation of metals (Mn+) in LBL assembly, followed by post-reduction to form (M0). This will allow the studies of catalytic reactions in the membrane domain. The REU students will also be involved in permeability and reactivity measurements, and material characterization through HRTEM mapping.

BUTTERFIELD
The focus of our research program is in the area of biophysical chemistry of membranes and on the interaction of nanoparticles with biological systems.

Neurotoxicity of Manufactured Nanoparticles: The focus of one aspect of our research program is in the area of toxicity to brain induced by manufactured nanoparticles (MNP). Specifically, we are interested in whether MNP, given peripherally, affect oxidative damage to brain membrane proteins and lipids centrally. This is a key issue of safety of widely used MNP (for example, ceria MNP used as gasoline additives, and MNP used in cosmetics). If brain oxidative stress occurs, what is the mechanism? The REU student will be involved in determining how these materials (specifically ceria of different size and shape) may be neurotoxic via oxidative processes. Indices of protein and lipid oxidation in brain membranes, and biological pathways involved will be pursued by the REU student. In addition, the REU student will use redox proteomics (pioneered in Butterfield’s laboratory) to identify oxidatively modified brain proteins following peripheral administration of MNP.

DAUNERT
Our group employs genetic engineering in the design of proteins and materials for use in sensing devices and protein separations. We are also interested in the development of integrated microand nanofabricated devices.

Stimuli-Responsive Materials with Integrated Protein Recognition: Currently, there are a limited number of biomaterials that have properties that allow them to perform in a reproducible, accurate, selective, and sensitive manner, and that are amenable to integration into devices that can be employed in a variety of applications (e.g., biosensors). To that end, we will design biologically inspired, advanced biomaterials that integrate protein recognition within micro- and nano-fabricated structures. One example is a stimulusresponsive material that incorporates the biological recognition of calmodulin (CaM) for its ligand, 7 phenothiazine, within a porous hydrogel or membrane network. CaM is a calcium binding protein that undergoes a large conformational change upon binding calcium, certain peptides, and phenothiazines. This binding is reflected as a volume change of the hydrogel or the pore architectures of polymeric membranes. The REU students will fabricate such stimuli-responsive hydrogels in the form of an array through microspotting for use as valves in microfluidics or as high-throughput analytical tools. By integrating the microspot array with a laser diode, the swelling of the microspot can be detected by the height change exhibited by the microspots. REU students will focus on one of three areas: (i) the development and characterization of novel polymer systems with tailored response characteristics (e.g., degree and rate of swelling response) through the molecular design of the polymer network, (ii) the development of methods of synthesis (e.g., surface initiated photopolymerization from SAM modified surfaces) to enable precise integration of these intelligent materials at the micro- and nanoscale with silicon, glass, or polymer surfaces, or (iii) application of these intelligent materials and demonstration of their response properties.

HILT
Our laboratory applies chemical engineering fundamentals to the rational design, synthesis and characterization, and application of novel materials. We are particularly interested in designing and fabricating intelligent polymer networks for application as recognition and/or actuation elements in innovative devices for microsensing, microarray, and other micro- and nanoscale applications. Biomimetic Recognitive Polymer Networks: A biomimetic template-mediated polymerization is applied to create polymers designed to mimic biological recognition pathways and at the same time exhibit other abiotic properties that are more favorable, such as greater stability in harsh environments. These biomimetic polymer networks are advantageous over natural receptors (e.g., proteins and antibodies) because they can be tailored to bind any molecule with controlled selectivity and affinity, provided that certain interactions exist. To achieve a relatively easy on/off-binding event, a non-covalent recognition process based on supramolecular interactions, such as hydrogen bonding, electrostatic interactions, hydrophobic interactions, and van der Waals forces, will be utilized. REU students will have the opportunity to develop novel polymer networks using molecular design for precise control over their binding properties for a target molecule.

JAY
The primary thrust of our program is the application of biocompatible nanoparticles in pharmaceutical chemistry.

Templating Solid Lipid Nanoparticles: The manufacturing processes for preparing most nanoparticle drug delivery systems involve microfluidization, high-pressure homogenization and/or extrusion steps that are not always readily scalable. We have developed a process referred to as, nanotemplate engineering, as an inexpensive, reproducible, and scalable nanoparticle formation process that avoids some of the issues associated with the preparation of other nanocarrier systems. This involves formation of a microemulsion precursor at elevated temperatures that, upon cooling, yields a suspension of solid nanoparticles. We have used the nanotemplate engineering process to prepare solid lipid nanoparticles containing antiinflammatory agents and will optimize the process for maximum drug entrapment and stability. Their stealth properties will be assessed by in vitro methods including adsorption of immunoglobulin and uptake by a macrophage cell line.

KALIKA
Research in our laboratory is focused on the investigation of morphological structure and dynamics in strategically designed polymeric materials; applications include polymer networks and nanocomposites for use as gas separation membranes, as well as novel polymer blends.

Polymer Chain Dynamics in Model Nanocomposite Systems: The presence of nanoscale structure in polymers can lead to substantial enhancements in the bulk properties of the material. The formulation of polymer nanocomposites via the introduction of nanoscale filler results in the creation of vast amounts of particle-polymer surface area, and particle-polymer interactions, as well as physical confinement effects, and has the potential to alter local chain conformation and relaxation dynamics. By systematically controlling the nature of the particle-polymer interface and corresponding composite morphology, we seek to understand at a molecular level how filler loading influences the relaxation characteristics of these nanocomposites and their ultimate thermomechanical and gas transport properties. Of particular interest is the relationship between nanocomposite behavior and the relaxation properties of polymers confined within isolated thin films. This project will examine nanocomposites based on both glassy and rubbery (network) polymer systems, with a focus on strategies to control the surface chemistry of the nanoscale filler. Undergraduate researchers will participate in the modification and functionalization of selected inorganic filler materials, as well as formulation of the nanocomposite specimens. The morphology and 8 corresponding dynamic relaxation characteristics of the resulting nanocomposites will be investigated using appropriate microscopy and spectroscopic techniques.

KNECHT
Research in our group is focused on using biological molecules, such as peptides and oligonucleotides, for the fabrication and organization of inorganic nanomaterials.

Biomimetic Synthesis of Heterogeneous Catalysts: Application of biologically programmable peptides bound to carbon nanotube (CNT) surfaces will be used as a template for the fabrication of bimetallic PdAu heterogeneous catalysts. To this extent, peptides discovered through phage display techniques, will be the driving force for the nucleation, growth, and spatial arrangement of Pd and Au nanoparticles along the CNT surface. The REU student will use this method to control the composition, structure, and interparticle distance in studying the structure-function relationship of bimetallic nanocatalysts. Additionally, this technique can easily be applied to many other materials.

KNUTSON
The focus of our research group is the use of CO₂ and CO₂-like (fluorinated) systems to provide unique solvent environments for the synthesis and processing of tailored materials.

CO₂P rocessing of Structured Nanoporous Silica to Enhance Functionalization: The goal of this research is to use CO₂ processing to tailor the functionalization and solute loading of surfactant templated mesoporous materials. We have recently demonstrated the ability to expand the pores of thin films and powders of surfactant-templated mesoporous silica using CO₂. Preliminary results indicate that exposure to CO₂ can also be used to reorient the functional silica precursors and improve the accessibility of functional groups within the structured porous materials. This project will demonstrate the tailoring of porous silica materials with reactive amine groups and the selective loading of the pores with solutes (e.g., dyes and enzymes) using CO₂ processing. The undergraduate researcher will participate in the synthesis and characterization of thin films of nanoporous functionalized ceramics. The materials properties and the functional group accessibility will be determined as a function of synthesis and CO₂ processing conditions.

WEI
Our research interests are at the interface between biochemistry and material science. Among others, we will incorporate protein design and engineering into the fabrication of novel nanoscale biological-inorganic materials.

Nanomaterial Assembly Based on Genetically Engineered Virus Capsid Proteins: The quest for new nanosized chemical architectures has promoted general interest in utilizing existent biogenic assemblies of the proper dimension, such as viruses. Viruses are made by two components, a nucleic acid genome (where the virus’ heredity information is stored), surrounded by a protective shell of protein called a capsid. Capsids can serve as scaffolds or building blocks for novel materials, nanosized reactors for well- controlled chemical reactions, or containers for specific labels in diagnostic imaging. We will use the cowpea chlorotic mottle virus (CCMV) capsid protein as an example to develop viral capsid based tools that have potential applications in targeted drug delivery, and to make nanoscale building blocks with integrated inorganic coating or core for the construction of novel biomaterials. More specifically, the REU student will first establish a bacterial expression system for the virus protein, which allows for convenient genetic modifications of the protein. Next, he/she will insert a metal binding peptide at specific target locations on the protein. After the virus protein self-assembles into a hollow shell, various salt solutions will be introduced followed by eduction to construct mineral coated and/or mineral filled nanospheres.