Marc D. Porter - US grants

This grant is in the general field of analytical and surface chemistry and in the subfield of spectroscopy of liquid solid interfaces. Professor Marc Porter of Iowa State University will use monomolecular films at solid surfaces to develop structure-property and structure-reactivity relationships relevent to surface chemical reactions. The use of electrochemically active functional groups specifically synthesized at the liquid-solid interface will allow the study of surface pH gradients. Optical spectroscopic methods will be used to probe the self assembled thiophenyl linkages at platinum and gold electrode surfaces. Surface infrared, spectroelectrochemistry and surface enhanced Raman spectroscopy will be used to study the reactivity and transformation of functional groups at the monolayer interface. Probe molecules will be used to determine Hammett linear free energy relationships. Spatially oriented arrays of pendant reactive functional groups (carboxylic acids, amines, esters and quinones) will be constructed and the effects of packing density, orientation and composition on reactivity will be explored. Electrochemical parameters will also be explored as a means to control reactivity and structure.

0088241
Porter
The objective of the proposed research is the design, development, and evaluation of a new paradigm for chip-scale bioanalytical laboratories. The goal is to uniquely couple the emerging fields of magnetically-based analyte labeling, DNA/protein microarray fabrication, microfluidic injection, and giant magnetoresistive sensors, forming a new class of integrated systems that address the enormous demand for high throughput sample screening in the functional genomics and proteomics arenas. These types of assays are also applicable to purity maintenance of public water and food supplies.

The objective of this research is to acquire research instrumentation for doing research on photonic waveguides and photonic devices, integrated biosensors, sensors for detection of toxic chemicals, organic semiconductors and neuron regrowth. These devices demand state of the art alignment capability with both front and back alignments. Iowa State has active research programs in each of the above areas, but does not have back and front sub-micron mask aligner. In this proposal, we plan to acquire a Suss MA/BA6 mask aligner capable of sub-micron lithography and of simultaneous back and front alignment so that device can be made on both sides of a substrate and devices in the submicron range can be made. This aligner will complement our existing array of tools, thereby allowing for a significant increase in our research productivity across a large number of disciplines.
Intellectual merit and Broad Impact
The proposed instrument meets a critical need at the University. No other comparable instrument is available at Iowa State. The instrument complements the following tools we own: Alcatel Deep RIE, poly-Si CVD furnace, Standard Si fabrication tools, Metal evaporators, Nanocrystalline Si plasma deposition reactors, Organic LED reactors, Single cantilever AFM tool. The instrument will allow faculty, students and research staff from Chemical Engineering, Electrical Engineering, Materials Science and Engineering, Mechanical Engineering, Physics, Chemistry and Biology to conduct experiments in the fields of photonic bandgaps, directed neural regrowth, nanocrystalline Si devices, integrated chemical and biological sensors based on OLED's and GMR devices, thin film resonators and multi-cantilver AFM tools for combinatorial diagnosis of surfaces. The instrument will be housed at the Microelectronics Research Center (MRC), an inter-disciplinary center at Iowa State where all the complementary facilities exist and are available for use by all the Iowa State faculty, staff and students. A full-time scientist will be in charge of the instrument and will maintain it in addition to some of the other tools. A maintenance account will be set up to charge the users a use-fee to pay for maintenance.
There will be significant impact on education of students, both graduate and undergraduate. This instrument, along with the existing instruments will be used for future experimental modules in courses dealing with fabrication of semiconductor, photonic and MEMS materials and devices Approximately 40 graduate students in many disciplines who use MRC facilities, and about 15 undergraduates who do research at MRC as part of their senior design or independent research projects will benefit from the acquisition of this instrument. A significant number of women and minority students are expected to participate in research activities made possible by the acquisition of this instrument. The proposed research activity has potentially broad impacts in the fields of electronic and photonic devices, sensors and neural science and engineering.

NER: Active Nanotribological Surfaces Using Monomolecular Films
PI: Sriram Sundararajan (Iowa State University)

Abstract

This proposal was received in response to Nanoscale Science and Engineering initiative, NSF 05-610, category NER. The objective of this research is design molecularly thin films that allow active manipulation of their surface energy and tribological (friction, lubrication and wear) behavior through the application of electric fields. The approach is to investigate two candidate alkanethiol based molecule systems using combined experimental and computational studies that include 1) synthesis, chemical and structural characterization of candidate films; 2) computational studies to qualitatively predict and understand the effect of electric fields on film behavior and 3) experimental tribological characterization of films in response to electrical fields.

Successful demonstration of the proposed research strategy can lead to applications in a whole range of industrial and consumer mechanical systems in which energy and economical losses associated with friction/wear can be significantly reduced. The films can also be used in systems where friction behavior needs to be controlled on demand such as biomaterial research (cells, tissues, fluid studies) and consumer applications (footwear for all-year traction). The project will also enhance undergraduate and graduate education by incorporating research results into engineering courses and leveraging freshman honors/student workstudy programs at Iowa State University to include undergraduates in research.

DESCRIPTION (provided by applicant): Viruses claimed a significant component of the nearly 15 million lives lost to infectious diseases in 2002. Viral transmission can occur through several routes, including contact with infected individuals, ingestion of contaminated food and water, or contact with a vector like mosquitoes and ticks. These pathways, which may only need to transmit a few tens to hundreds of viruses to trigger an infection, will only become more prevalent as the globalization and urbanization of our planet accelerates. Thus, the ability to detect these and many other pathogens and disease markers rapidly and at very low levels stands as an extremely challenging proposition central to pubic health monitoring, food/water safety, and bioterrorism. While recent breakthroughs have led to the capability to detect viruses and other nanometric targets (e.g., proteins) at single and double digit levels after capture on a solid phase, the time required for sample/label incubation remains a bottleneck for transitioning to the surveillance/monitoring arena. This proposal seeks to redefine assay speed by exploring the potential of nanoporous gold (NPG) to function as a flow-through capture substrate for the efficient extraction of viruses and other comparably-sized pathogens and disease markers (e.g., antibodies), while at the same time accounting for other considerations needed for effective performance. The basis for this strategy rests with predicted improvements in the mass transfer rates, and thus the binding rates, for both the capture and labeling steps in heterogeneous assays that may be realized by flow through a nanoporous material. Models project potential increases in binding rates of more than two orders of magnitude with respect to the most effective of the known approaches. Two groups of experiments are therefore planned to assess this possibility using gold nanoparticle-based surface enhanced Raman scattering (SERS) measurements. In the first group of experiments, NPG membranes of varied pore size will be fabricated, derivatized, and tested as flow through extraction phases for the model virus feline calicivirus, FCV. FCV, which has ~30-nm diameter and is an effective norovirus simulant, will enable an in-depth, systematic assessment of extraction with respect to pore size. These studies will also test the effect of flow rate on capture and label efficiency, and collectively will provide a set of predictive rules for performance optimization in other potential applications. In addition, experiments will be conducted to minimize the impact of nonspecific adsorption by use of blocking agents, as well as potential complications from membrane clogging through the incorporation of sample prefilters. In the second group of experiments, these guidelines will be applied to assays for the detection of FCV in several matrices, including whole goat serum, tap water and groundwater. PUBLIC HEALTH RELEVANCE: This grant proposal seeks to redefine the speed of heterogeneous immunoassays by exploring the potential of nanoporous gold (NPG) membranes to function as flow through capture substrates for the rapid, efficient and selective concentration of nanometrically-sized pathogens (e.g., viruses and proteins). The basis for this strategy rests with: (1) the predicted improvements in the mass transfer rates, and thus the binding rates, for both the capture and labeling steps that may be realized by flow through a nanoporous material;and (2) the high sensitivity of a readout technique that uses modified gold nanoparticles and surface enhanced Raman scattering (SERS). To carry out the above tasks, we have assembled a team of scientists and engineers from the University of Utah Departments of Chemistry, Chemical Engineering, and Bioengineering, and from the Arizona State University School of Materials.

PROJECT SUMMARY Tuberculosis (TB) is the world's second deadliest infectious disease, overshadowed only by HIV/AIDS. A prompt, accurate diagnosis is required for effective control of TB, but in endemic regions, patient management is initially based upon clinical suspicion and low-sensitivity sputum microscopy. Confirmatory culture testing is slow, costly, and not routinely available. There is currently a lack of early diagnostic tests, which, when combined with marginal clinical laboratory infrastructure, can result in the under- or over-diagnosis of TB. The former impacts successful patient outcomes and efforts to block secondary transmission, while the latter promotes unnecessary treatment and poor utilization of healthcare resources. The number of new TB cases diagnosed in the U.S. remains sizable, with a significant proportion of infections occurring in individuals who have limited access to health care, are foreign-born, and/or are HIV-infected. We have assembled a team of clinicians, TB experts, immunologists, and chemists to develop a new test for TB. Using surface-enhanced Raman spectroscopy (SERS) to significantly lower the limit of detection, we propose the development of an inexpensive, rapid, and accurate point-of- care immunodiagnostic assay utilizing multiplexed monoclonal antibodies to concurrently identify a panel of Mycobacterium tuberculosis target antigens that have been identified in body fluids during active infection. It is anticipated that a paired test to detect M. tuberculosis antigens in both serum and urine will significantly improve the overall sensitivity of antigen detection, redefining the way TB is managed. This approach is expected to provide the qualitative and quantitative data necessary for rapid, reliable diagnosis in a variety of settings, allowing the prompt accurate treatment of TB, as well as immediate infection control measures designed to avert transmission to others. The impact of the approach is amplified as the SERS platform can be adapted to the diagnosis of other infectious diseases by changing the array of detection antibodies.

DESCRIPTION (provided by applicant): Invasive Aspergillosis (IA) is a devastating and frequently fatal infection in immunocompromised patients, in part because of poor early detection tools. The ability to promptly launch antifungal therapy for Aspergillosis and other invasive fungal diseases is critical for positive patient outcomes. However, early detection is complicated by low levels of antigenic markers that signal disease onset and by poor specificity of current diagnostic assays. The aim of this proposal is to develop an antibody-based diagnostics platform comprised of new monoclonal antibodies coupled with the ultrasensitive detection capabilities of surface enhanced Raman spectroscopy and gold nanoparticle sandwich assays. To address the challenges in the early detection of IA, we have assembled a collaborative research team of scientists from the University of Utah and North Dakota State University composed of immunologists with expertise in monoclonal antibody development and screening for Aspergillus spp;medical microbiologists with strengths in basic mycology, fungal assay development and validation;analytical chemists with a strong focus in the creation of novel, ultrasensitive and selective diagnostic tests;and infectious disease clinicians with proficiency in the design and implementation of patient-oriented research. We will address the specific aims of this project in two phases. The aims for the R21 phase of the project are: (1) Identify protein-based fungal targets through the development of monoclonal antibodies from unique, stage-specific biomarkers of Aspergillus spp. (2) Evaluate monoclonal antibody combinations with surface enhanced Raman spectroscopy-based sandwich immunoassay techniques. (3) Define assay performance metric comparisons using diverse human sample matrices. Upon meeting the milestones of the first stage of the project, the aims of the R33 phase are: (1) Characterize fungal target proteins based on growth stage specificity. (2) Optimize analysis protocols to maximize fungal detection. (3) Standardize components of a unique analysis kit for early clinical Aspergillosis diagnosis. The detection strategy created through the successful completion of this project will redefine the diagnosis of IA through augmented sensitivity and specificity, permitting treatment at the earliest stages of disease.

DESCRIPTION (provided by applicant): Early diagnosis is critical to the treatment of cancer and many other diseases. Today's diagnostic methods, however, often rely on the detection of individual and, in a few instances, small numbers of disease markers that have limited value in early diagnosis. Importantly, there is a growing body of evidence demonstrating that the diagnostic, prognostic, and stratification accuracy can be improved by detecting the presence of a large number of relevant biomarkers in serum samples. To this end, the creation of a platform capable of high throughput and high detection sensitivity stands as a vital first step. Such a platform must also handle samples of preciously limited volume and meet the demand for ever shorter turn-around-times. These same attributes are at the heart of advances in the discovery and screening of new disease markers. This multidisciplinary project at the University of Utah seeks to create a new nanotechnology-based platform - the multiplexed magnetoresistive immunoassay (mMRIA) system - for the early detection of cancer. It targets pancreatic cancer as the first step in platform development and performance validation. Pancreatic cancer is the fourth most common cause of cancer-related deaths in the United States. The 5-year survival rate of ~4%, the lowest of any cancer, underscores the importance of the project. Project goals include: (1) strategies to markedly enhance magnetoresistive sensor performance (e.g., noise and signal attributes, internal response calibration, design and layout of the addresses on the capture substrate array, separation between sensor (i.e., reader) and scanned array, and analytical descriptors of signal transduction); (2) synthesis of novel magnetic nanoparticles to serve as labels with a strong magnetic signature; (3) integration of advances in hydrodynamics to increase sample and label flux to the solid phase array as a means to reduce TAT and simultaneously lower the background signal; and (4) design and construction of instrumentation to quantitatively read thousands of immunoassay addresses in less than one minute. RELEVANCE (See instructions): This project is focused on the development of a nanotechnology-based platform for the early diagnosis of cancer. The goal is to construct and test this technology, which is based on the magnetics concepts that read the hard disk drive in most of today's laptop computers and portable music media players, that will simultaneously and rapidly detect large numbers of disease markers at unprecedented levels of sensitivity.

DESCRIPTION (provided by applicant): This proposed research focuses on the advanced development and validation of an innovative, extensible diagnostics platform to markedly improve early cancer detection and cancer risk assessment through the ultrasensitive readout of biomarker panels. The creation of a surface-enhanced Raman scattering (SERS) immunoassay diagnostic platform, realized by coupling sensitive SERS detection with nanoparticle labels, enhanced analyte delivery, and immunoassay architectures, will result in a simple platform capable of multiplexed biomarker detection. This intelligent use of a panel of biomarkers will serve as the cornerstone in making subclinical cancer detection a reality. Integral to this work is the use of pancreatic adenocarcinoma (PA) as a disease model to validate the platform. PA exhibits traits common to most diseases that progress asymptomatically, including the unavailability of one ideal tumor marker with high clinical sensitivity and specificity. Since development of PA arises from a range of causative mutations in individuals, a panel of multiple biomarkers with overlapping detection capabilities is likely to provide improved accuracy. Assembly of such a panel from markers that have demonstrated limited correlative value individually provides a vehicle to assess the figures of merit and multiplexing ability of the SERS platform. Currently, our ability to identify health risk, disease susceptibility, and response to therapy remains unreachable due in part to our technical inability to easily screen a single sample for the large number of biomarkers that potentially make up a "disease map" and to do so at costs that enable routine testing for everyone. The SERS platform is designed to remove this hurdle. Once validated, the platform could also be used for marker and marker panel discovery and is uniquely suited for rapid deployment as a cost-effective, portable, and robust system for multiplexed diagnostic assays in a clinical setting or to form an essential part of the personalized medicine infrastructure. PUBLIC HEALTH RELEVANCE: This proposal seeks to make early cancer detection and the associated promise of improved outcomes accessible to the general public. Current technical limitations have hindered the ability to rapidly screen large numbers of biomarkers from individual patients, a method purported to have improved diagnostic, prognostic, and therapeutic efficacy over a single biomarker. The project proposes developing a platform that uses a rapid, cost-effective optical detection technology to simultaneously measure hundreds of biomarkers in a single drop of blood.

DESCRIPTION (provided by applicant): Invasive Aspergillosis (IA) is a devastating and frequently fatal infection in immunocompromised patients, in part because of poor early detection tools. It presently kills 52% of those infected. The ability to promptly launch antifungal therapy for Aspergillosis and other invasive fungal diseases is critical for positive patient outcomes. However, early detection is complicated by low levels of antigenic markers that signal disease onset and by the poor specificity of current diagnostic assays. The aim of this proposal is to develop an antibody- based diagnostics platform comprised of new monoclonal antibodies coupled with the ultrasensitive detection capabilities of surface enhanced Raman spectroscopy and gold nanoparticle sandwich assays. To address the challenges in the early detection of IA, a collaborative research team of scientists from the University of Utah and North Dakota State University has been assembled and includes immunologists with expertise in monoclonal antibody development and screening for Aspergillus spp; medical microbiologists with strengths in basic mycology, and in fungal assay development and validation; analytical chemists and nanotechnologists with a strong focus in the creation of novel, ultrasensitive and selective diagnostic tests; and infectious disease clinicians with proficiency in the design and implementation of patient-oriented research. This R21 grant application will advance this concept using Aspergillus fumigatus (A. fumigatus) - the most common cause of IA - as the proof-of-principle target. The specific aims for this R21 grant application are: (1) To generate unique, stage-specific biomarkers and associated monoclonal antibodies (mAbs) for A. fumigatus. Murine mAbs will be generated against cellular components and secreted products of A. fumigatus. (2) To identify and optimize multiplexed mAb combinations for a sandwich immunoassay based on surface enhanced Raman scattering (SERS), and mAb-coated gold nanoparticle labels. (3) To assess the performance of the assay using biological sample matrices. The detection strategy created through the successful completion of this project will redefine the diagnosis of IA through augmented sensitivity and specificity, permitting treatment at the earliest stages of disease. PUBLIC HEALTH RELEVANCE: Invasive aspergillosis (IA) is a devastating, frequently fatal infection in immunocompromised and immunosup- pressed patients. Unfortunately, the ability to promptly launch antifungal therapy for IA and other invasive fun- gal diseases is compromised by the poor clinically sensitivity, clinical specificity, and prognostic value of exist- ing diagnostic tools. Until IA can be reliably identified at early stages, the morbidity/mortality attendant with this dreadful disease will remain unacceptably high. The overall goal of this project is to develop a rapid, cost effec- tive laboratory test that will serve as a cornerstone for the confident early diagnosis of IA.

DESCRIPTION (provided by applicant): There is a growing need for a highly efficient, simple, and easy to use quantitation method for multiplexed marker analyses. We hypothesize that differences in analyte flux to different addresses in a heterogeneous array-based platform can serve as an effective means to simultaneously determine the absolute concentration of a number of analytes with only the need to add a single calibrant to the sample. This proposal details a reduction to practice of technology that will afford a simple and cost-effective approach to determine the concentration of each marker - irrespective of the number of markers - without requiring the creation of calibration curves or the use of calibrants. The platform is extensible - meaning it could be deployed for genomic and metabolic studies as well as for platform proteomic assays - and could be applied to other readout methods.

DESCRIPTION (provided by applicant): Recent events have placed the need for the development of reliable techniques for the rapid, low-level detection of NIAID Category A Priority Pathogens (Category A Pathogens) at an even more critical level. This project will develop deployable, nanoparticle-based, surface enhanced Raman scattering (SERS) diagnostic tests to fill this need. In so doing, this project will focus on serum markers for three well characterized Category A Pathogens (i.e., Bacillus anthracis, Clostridium botulinum toxin, and Yersinia pestis) in devising and performance-validating a multiplexed diagnostic panel based on the ultrasensitive detection of extrinsic Raman labels (ERLs) selectively bound to captured active pathogen antigens. ERLs will use unique Raman reporter molecules (RRMs) and monoclonal antibodies (mAbs) to selectively bind to captured antigens and to generate a markedly enhanced signal for ultra-low-level detection. Concurrently, we will also design and manufacture prototypes of a lightweight integrated, closed, sample-to-answer platform capable of reading the characteristic SERS spectrum from the ERLs when excited by a new diode laser. The platform will be field-deployable, have a desktop printer-size footprint, and have a readout of ~2 min for a 96-well microplate. As assays for the deactivated pathogens are validated in the laboratory the procedures will be transferred into a BSL-3 facility where methods for the active Category A Pathogen markers will be validated. When the prototypic Raman instruments and panel kits are available, they will be beta-tested and performance validated in the research laboratory (with deactivated markers) and in the BSL-3 facility (with active markers) at the U.S. Army's Dugway Proving Ground (DPG). This project represents a partnership between scientists and engineers at the University of Utah, B&W Tek, Inc. (a global leader in Raman spectroscopy and related automated instrumentation), and DPG.

PROJECT SUMMARY/ABSTRACT Preventative or curable major diseases such as cancer, heart disease, and diabetes can be successfully treated if detected early in their development via routine physician visits and preventative screening. However, many populations of the world are medically underserved due to resource limitations, geographical location and socio-economic barriers. The overall goal of this project is to develop a portable, inexpensive and easy-to- use point-of-care (POC) platform that can be deployed to prescreen such communities for many of the common, clinically significant diseases in these underserved communities. For development of our initial proof of concept, our integrative team will closely collaborate with partnering physicians in Mongolia on a platform for early diagnosis of hepatocellular carcinoma (HCC) and Hepatitis B and C, which are closely linked to HCC, both of which have a high incidence in this country and in the surrounding region. We propose the development of a portable, easy-to-use, low-cost immunosorbent assay for blood-borne biomarkers of these diseases using a quantitative vertical flow assay (q-VFA) with Raman readout. This platform, which is based on an extensive body of work at the University of Utah, provides a short sample-to- result turn-around-time and can be administered, for example, by a local health care worker or community leader. If positive, referral for further diagnostic evaluation is needed, and the patient can be directed to their nearest medical facility.