Summer2012

AppliedBiotechnology Research

Experience

University of California, Santa Barbara

Lab Mentor: Hannah KallewaardFaculty Mentor: Kevin PlaxcoDepartment: Chemistry and Biochemistry

Kaisha BenjaminChemical EngineeringHoward University

Daniel ConchaMechanical Engineering and Materials Science

Duke University

Lab Mentor: Teyeb Ould-ElyFaculty Mentor: Dan Morse

Department: Molecular, Cellular and Developmental Biology

DEVELOPMENT OF A HERPES ELECTROCHEMICAL SENSORHerpes Simplex Virus type-2 (HSV-2) is the primary cause of recurrent genital Herpes. Most patients that have HSV-2 are unaware of their infection because they are either asymptomatic or their doctor is unable to recognize that their symp-toms are a result of the virus. This can lead to the unintentional transmission of the virus from mother to child or between partners. This project ultimately aims to increase the occurrence of point-of-care diagnostics through the fabrication of a HSV-2 Electrochemical-DNA (E-DNA) sensor. Point-of care diagnostics allows a doctor to rapidly and accurately diagnose and treat a patient within a single doctor’s appointment. The E-DNA sensor used in this project consists of a gold electrode with a “scaffold” structure. The scaffold is comprised of a 27 base strand of DNA labeled with a methylene blue redox tag at its 3’ end and a thiol group at its 5’ end. The thiol group is used to covalently bond the DNA to the electrode surface in a self-assembly manner. The sensor also consists of a strand of PNA with a peptide epitope at the distal end. We use Pep-tide 55, an eighteen amino acid sequence from Glycoprotein g2, a glycoprotein found on HSV-2 that the human immune system recognizes. When the HSV-2 Antibody binds to the Peptide 55 epitope, a decrease in electron transfer between the redox tag and the gold electrode occurs, thus reducing the amount of current observed.

SYNTHESIS AND CHARACTERIZATION OF ANODE MATERIAL FOR LIGHTWEIGHT AND EFFICIENT BATTERIESToday’s global energy demands have placed a huge emphasis on battery development. Lithium-ion batteries have been found to outper-form alkaline, Ni–Cd, and lead acid batteries. Though lithium-ion batteries have been implemented in small electronic devices, further research seeks to optimize battery performance (i.e. power output, capacity, cyclability and weight) in hopes of integrating them into larger energy-dependent industries (Military, Aerospace, Medical devices, Automotive, etc.). Currently, graphite is the primary anode material for lithium-ion batteries due to its long cycle life, abundant material supply and relatively low cost. However, the graphite an-ode has the disadvantage of low energy density (375mAhg-1). To increase power output and capacity, we have developed a Sn/Graphite nanocomposite anode, using our previously developed vapor diffusion catalytic synthesis method. I have altered various experimental parameters with hopes of loading more homogenously dispersed Sn into the graphite matrix. The higher theoretical capacity of Sn than graphite dictates that increased homogenous loading within the graphite matrix should improve battery life, energy capacity and power output. After loading the nanocomposite into half-cells, the material is then analyzed through cycled Arbin Testing and Electrical Impedance Spectroscopy as well as Scanning Electron Microscopy, X-Ray Diffraction and Thermogravimetric Analysis. The resulting information will allow us to further understand how to improve Sn loading into the graphite matrix and the resulting effect on battery performance. If successful, this will serve as a critical stepping-stone in battery development, and will encourage new applications for lithium-ion batteries as a lightweight, safe and reliable alternative energy source.

Lab Mentor: Chrysafis AndreouFaculty Mentor: Carl MeinhartDepartment: Mechanical Engineering

Alan GonzalezElectrical EngineeringCalifornia State University, Los Angeles

Ashleigh JonesBiology

Jackson State University

Lab Mentor: William RyanFaculty Mentor: Jim Blascovich

Department: Psychological and Brain Studies

PICOLITER SCALE DROPLET GENERATOR FOR PRECISION MIXINGA microfluidic double droplet generator was fabricated to investigate mixing in picoliter scale droplets. Microfluidics is the process of designing and making devices that can sustain small volumes of fluid (<1 μl). The precise control provided by microfluidics can allow the investigation of many chemical reactions such as the aggregation of silver nanoparticles used for chemical detection. Here, we use a UV-curable polymer to fabricate the double droplet generator. This particular material was chosen because it is fast and easy to fabricate, and allows for control of the surface properties of our devices. By making the material hydrophobic we can generate water-in-oil droplets that contain fluorescent particles and in this way visualize the mixing inside the droplets.

AUDITORY IMPACTS ON CARDIOVASCULAR MEASURESHundreds of products are made each year that incorporate the sounds of a heart beating in order to relieve stress. These products are mainly manufactured for infants but similar products are marketed to adults as well. People spend large amounts of money on these pricey products, despite the fact that there is no scientific re-search that shows whether these products actually relieve stress or not. The main goal of this experiment was to find out if heart sounds were stress relieving for young adults. We believed that heart sounds would be more effective in lowering the level of stress in participants rather than Pachelbel’s canon and nothing. We believe that if heart sounds have a positive effect on young adults then they would have the same effect on babies. We had participants listen to heart sounds, Pachelbel’s canon or nothing at all and then perform a stressful math task. We examined their self reported stress and physiological stress, assessed through blood pressure, heart rate and impedance. Cardiovascular measures suggest that participants who listened to heart sounds were threatened more than those who listened to Pachelbel or nothing. Physiological data and self-reported data did not correlate. The results obtained suggest that heart sounds are somewhat threatening instead of relaxing.

Lab Mentors: Roxanne Croze, Lyndsay LeachFaculty Mentor: Dennis CleggDepartment: Molecular, Cellular and Developmental Biology

Sandra NakasoneAgricultural and Biological EngineeringUniversity of Florida

Mayra PerezMollecular, Cellular, and Developmental Biology

University of California, Sanra Barbara

Lab Mentor: Vivek Gupta Faculty Mentor: Samir Mitragotri

Department: Chemical Engineering

MONITORING STEM CELL-DERIVED RETINAL PIGMENTED EPITHELIUM IN OCULAR DISEASEAge-related macular degeneration (AMD) is a disease that causes progressive deterioration of a highly specialized cell type, the retinal pigmented epithelium (RPE), within the macula. The macula, located in the central posterior part of the eye, is responsible for fine acuity vision. Death of RPE cells within the macula leads to loss of the central vision. AMD primarily affects adults over the age of 70 and is the leading cause of blindness in developed countries, yet there are currently no treatment options for the most common form of the disease; Dry AMD. Use of human embryonic stem cells (hESC) has been proposed as a novel approach to slow the progression of AMD. HESC spontaneously differentiate into RPE, which can be used therapeutically for AMD by transplantation, however, little work has been done to characterize the behavior of these cells. It is crucial to ensure transplanted cells maintain their differentiated state and do not cause inflammation in the host. We hypothesize that different fluorescent reporters can be used in stem cell derived RPE (hESC-RPE), allowing us to monitor RPE cell identity and inflammation. Cur-rently, we are testing markers for RPE identity (RPE65, Best1) and inflammation (STAT1) using lentiviral vectors and fluorescent imaging techniques. Our preliminary results indicate that hESC-RPE mature correctly and behave as healthy RPE in vitro. After characterization, these cells will be transplanted into an in vivo rat model of retinal dysfunction and further studied. Success of this study will lead to better cell-based therapies for treating AMD patients.

MUCOADHESIVE INTESTINAL DEVICES FOR ORAL DELIVERY OF MACROMOLECULES Despite being an attractive and patient compliant approach, oral drug delivery has been extremely challenging and has not been available for administration of peptides and other macromolecules such as insulin because of (i) enzymatic degradation in the gastrointestinal tract and (ii) very poor permeability across intestinal epithelium. To address these challenges, we hereby report development of a novel muco-adhesive device, which will deliver clinically relevant doses of macromolecules via absorption through intestinal epithelium while avoid-ing gastrointestinal degradation. Flexible design of these devices enables them to encapsulate varying amounts of therapeutic agents, and to combine synergizing approaches such as inclusion of biologically safe chemical permeation enhancers so as to maximize oral bioavail-ability. In this project, devices were fabricated using proprietary mixtures of different mucoadhesive polymers (carbopol, chitosan, pectin, and sodium carboxymethylcellulose) using a hydraulic press. Fabricated devices were tested for (i) efficacy in releasing fluorescent dye, and a test peptide FITC-insulin in-vitro; and (ii) mucoadhesive strength between device and porcine intestine ex-vivo. Results indicated that mucoadhesive devices effectively released encapsulated dye and peptide over 7 hours. Drug release kinetics could be fine-tuned by altering the ratio of polymers. All devices showed significant mucoadhesion enabling them to adhere with a force of approximately 100 times their own weight. Further studies need to be performed to optimize the polymer blend, and to test efficacy of chemical permeation enhancers in enhancing drug release/transport from the devices. Overall, mucoadhesive devices provide an attractive non-invasive alter-native for oral delivery of macromolecules, otherwise being administered via injections.

Alvaro SolanoMechanical EngineeringCalifornia State University, Fullerton

Lab Mentor: Oshin NazarianFaculty Mentor: Frank ZokDepartment: Materials

COMPRESSIVE RESPONSE OF ENERGY ABSORBING POLYURETHANE FOAMSThe improvised explosive device (IED) has become a large threat to personnel safety. The shockwave propagated through the detonation process is the main component that is harmful to personnel. Recently, materials have been developed to mitigate the sharp peak pressures observed in this type of event. Much interest lies in commercially available energy-absorbing foams, such as Zorbium®. The motivation for this project is two-fold. The first goal is to understand the behavior of polyurethane foams by testing several commercially available foams. The second objective is to compare these foams against other energy absorbing materials, and to establish whether a composite utilizing a cellular structure with embedded foams is advantageous.