Valerie Sheares Ashby, Ph.D. - US grants

The need for heteroatom functionalized biomaterials with tunable thermal, mechanical and solubility properties that also meet biocompatibility and biodegradation requirements is significant. The utility of functionality in these materials is evident in a number of applications ranging from drug delivery to gene therapy where the ability to attach targeting groups, cell fusion promoters, fluorescent labels, mechanical property-enhancing groups, etc. would significantly advance performance. While there are a variety of new materials that have been proposed to address the lack of functionality in synthetic polymeric biomaterials, many of them fall short because of poor biocompatibility, poor biodegradability or limited design capability and control. The development of a methodology to incorporate these needed functional groups into classes of materials that already meet many of these criteria is a viable approach. As such, the proposed research effort has three goals:
1) the design of synthetic routes that yield monomers capable of being polymerized via step growth reactions,
2) the synthesis of a variety of functionalized polyester, polyether and polycarbonate homopolymers and copolymers, and
3) the derivation of the structure-property relationships for these functionalized polymers, examining thermal, mechanical, processing, biocompatibility, biodegradation and structure-function characteristics of the materials.

Intellectual Merit. The success of these materials will have a significant impact on this area of advanced biomaterials by providing a method of tailoring chemical functionality and optimizing physical, mechanical and biological properties. The approach is a rational one with significant potential as the work will focus on classes of materials that are FDA approved. Moreover, the starting materials used, disubstituted dienes, for example, are routinely produced in 85% overall yield on a 100 gram scale with greater than 99% purity, making them excellent starting materials for derivatization. While the initial thermal and mechanical property analysis will be conducted in laboratories at UNC, further analysis of these materials will be accomplished in collaboration with Professor Robert Langer's group at MIT. Collaborations with colleagues at MIT and UNC will combine expertise in polymer synthesis, polymer characterization and biomaterials to make significant contributions to the field.

Broader Impact: This project will advance the understanding of the role of various functional groups in well-known aliphatic biomaterials, while promoting teaching and training. Graduate students will learn how to solve problems by starting with monomer synthesis moving to the polymer synthesis then to the material properties and applications. Undergraduates and high school student researchers will be presented with intriguing, relevant problems that can be answered in the laboratory using organic synthesis and analytical chemistry. The multidisciplinary interaction will also be an educational opportunity for all students, as they will be active participants in the collaborative research. Additionally, it is expected that the research results will be incorporated, where appropriate, into the teaching of undergraduate organic chemistry and of graduate polymer chemistry to help students appreciate the utility of basic concepts.

The purpose of the North Carolina Alliance to Create Opportunity through Education (OPT-ED) AGEP is to substantially enhance efforts in North Carolina to increase the number of underrepresented minority (URM) students receiving PhD degrees and ultimately entering the professoriate in science, technology, engineering, and mathematics (STEM) fields. The proposed AGEP project combines two existing Minority Graduate Education (MGE) projects at the University of North Carolina at Chapel Hill (UNCCH) and jointly at North Carolina State University (NCSU) and North Carolina A&T State University (NC A&T). Immediately after the MGE grants were awarded, the three schools formed an alliance; one year later, formed a formal network that included all NSF-HRD supported URM initiative projects in North Carolina: the Louis Stokes Alliance Minority Participation Program, the Historically Black Colleges and Universities, and Centers for Research Excellence in Science and Technology, in addition to the North Carolina Math Science Education Network, a K-12 program with sites at college campuses across the state. Thus, OPT-ED is the formal alliance of the three institutions under one program and the building and strengthening of the collaborative network or alliance among NSF-supported URM initiative projects in the state.

Intellectual Merit. OPT-ED.s strength and uniqueness is its incorporation of NSF URM initiative
programs in North Carolina into a broader alliance to form student pathways to the PhD degree and the professoriate. OPT-ED and its network partners recognize that STEM PhDs are not the result of graduate programs alone, but are fashioned from the intellectual building blocks that occur in middle and high school. The logic behind the development of OPT-ED stems from the conceptualization that the connecting of programs with common goals, to advance the participation of URM students in STEM fields would strengthen this effort in a much broader fashion. The key is the participation of programs from the education spectrum ranging from middle school to PhD programs. This in itself is a unique development. This framework allows a clear pathway to be evident in that students in the middle school program can receive guidance and support all the way through to the completion of the PhD. These connections will enhance the possibility of students continuing to receive encouragement, reinforcement, and expanded research experiences that will increase their successfully pursuing STEM graduate degrees.

Broader Impacts. Through integrating the resources of all NSF-HRD (and ultimately other) diversity
programs in the state, OPT-ED will have a broad impact across several educational levels, the state of North Carolina, the Southeast and, with the eventual production of PhD recipients, the nation. Thus, OPTED will serve as a comprehensive project for recruiting, mentoring, and graduating URM students in STEM PhD programs, and to carry out strategies to identify and broadly support URM students who want to pursue graduate studies and careers. The norms of inclusiveness at the AGEP institutions and the relationships that have been forged in Phase I and will be strengthened in Phase II will endure well past the termination of grant support. Given its goals and objectives, this alliance and the expected expansion of network programs will continue to work in partnership to provide URM students with opportunities to pursue PhD degrees and prepare for the professoriate well into the future.

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SES-0548858
Henry Frierson
University of North Carolina at Chapel Hill

SES-0549031
Robert Schwab
University of Maryland, College Park

SES- 0548909
Steven Ullmann
University of Miami

SES-0549057
Anne Donnelly
University of Florida

SES-0548986
Orlando Taylor
Howard University

The goal of the Atlantic Coast Social, Behavioral, and Economic Sciences (AC-SBE) Alliance, consisting of Howard University, the University of Florida, the University of Maryland at College Park, the University of Miami, and the University of North Carolina at Chapel Hill, is to increase the number of under-represented minority students receiving PhD degrees in the social, behavioral, and economic (SBE) sciences and ultimately entering the professoriate. All five universities are among the nation's leaders in awarding PhDs in the SBE fields to underrepresented minority students. The plan for the AC-SBE Alliance includes elements designed to help students at each step as they move from undergraduate school into graduate programs and onto the professoriate. The consortium has four objectives: (1) Recruit and prepare undergraduates to pursue a PhD in SBE fields, (2) Assist students in the transition from undergraduate to graduate study, (3) Retain PhD students and increase degree completion rates, and (4) Prepare future SBE faculty for success. Although each of the five schools in the AC-SBE alliance has unique features, the AC-SBE Alliance will include a number of overarching activities that will involve all five universities. For one example, the Alliance will build upon Howard University's Summer Institute that prepares future faculty in the STEM disciplines to launch a parallel SBE component. Also, entering AC-SBE students will be invited to participate in a one-week course Introduction to Data Analysis for the Social Sciences at the Odum Institute for Research in the Social Sciences at the University of North Carolina at Chapel Hill. The Odum Institute will also offer a number of videoconference short courses for AC-SBE students. Efforts will be made to ensure that the students in the SBE Alliance have further opportunities to interact and network at conferences such as the NSF-supported EMERGE.

Broader Impacts. Through integrating the resources of the five AC-SBE Alliance institutions, AC-SBE will have a broad impact across a wide region of the country in the eventual production of SBE PhD recipients. Thus, AC-SBE will serve as a comprehensive project for recruiting, mentoring, and graduating URM students in SBE PhD programs, and to carry out strategies to identify and broadly support URM students who want to pursue graduate studies and academic careers. The norms of inclusiveness at the AC-SBE Alliance institutions and the relationships that have been forged will endure well past the termination of grant support to continue efforts to ensure the significant numbers of minority students pursue and receive PhD degrees and enter the professoriate.

TECHNICAL SUMMARY: The need for completely amorphous elastomeric biomaterials with tunable thermal, mechanical and degradation properties is significant. While crystalline materials are suitable for several biological applications, in many cases, implanted tissue engineering scaffolds, drug delivery depots and in vivo sensing materials are in mechanically dynamic environments in the body and must sustain and recover from various deformations without mechanical irritations to the surrounding tissues. In addition to decreasing tissue damage, elastomeric materials would also address needs ranging from tissue engineering scaffolds with desired mechanical properties to completely amorphous drug delivery devices with faster controlled release profiles to flexible mechanical devices such as drug eluting stents. Despite the recognized importance of elastomeric biomaterials, there have been only a few examples reported in the literature. In this project, synthetic strategies will be developed that will lead to a variety of new elastomeric biomaterials. Specifically, the following will be accomplished: 1) the design of synthetic routes that yield monomers capable of being polymerized via step growth reactions, 2) the synthesis of a variety of polyester, polyester ether and polyester urethane homopolymers, copolymers, thermoset and thermoplastic elastomers, and their polar functionalized derivatives and 3) the study of the structure-property relationships for these materials, examining thermal, mechanical, solubility, processing, biocompatibility and biodegradation characteristics. While the initial thermal and mechanical property analysis will be conducted in laboratories at UNC, further bidegradation and biocompatibility analysis of these materials will be accomplished in collaboration with Professor Moo Cho in the UNC School of Pharmacy. Processing will be completed in collaboration with Professor Joseph DeSimone in the UNC department of chemistry. A detailed analysis of mechanical properties, particularly related to shape memory behavior will be a collaborative effort with Professor Ken Gall at Georgia Tech. Collaborations with colleagues at UNC and GT will combine our expertise in polymer synthesis, with characterization, processing and biomaterials knowledge to make significant contributions to this area of research.

NONTECHNICAL SUMMARY: The biomaterials currently used in applications such as drug delivery stents and tissue regeneration scaffolds typically are rigid materials that often cause damage to the surrounding tissues. The new materials that will result from this project will have properties that are more compatible with soft tissue. Despite the recognized importance of designing these soft elastomeric degradable biomaterials, there have been few examples reported in the literature. In this research, synthetic strategies will be developed that lead to a variety of these types of new elastomers. The success of these materials will have a significant impact on this area of advanced biomaterials by providing methods for producing elastomers as well as for tailoring the chemical functionality, physical, mechanical and biological properties. This project will also promote teaching and training of graduate students, undergraduates and high school student researchers. Each will be presented with intriguing, relevant problems that can be answered in the laboratory using organic synthesis and analytical chemistry. The research results will be incorporated into the teaching of undergraduate organic and of graduate polymer chemistry to help students appreciate the utility of basic concepts. The major outreach efforts of this project include continuing work in a recently established UNC Chapter of the National Organization of Black Chemists and Chemical Engineers for which the PI is the faculty advisor. The PI will also continue to serve as a mentor in the Project SEED program, which encourages economically disadvantaged high school students to pursue career opportunities in the chemical sciences.

SES-0750385
Henry Frierson
Anne Donnelly
Carolyn Tucker
University of Florida

SES-0750663
Kim Nickerson
Johnetta Davis
Robert Schwab
University of Maryland, College Park

SES-0750657
Steven Ullmann
University of Miami

SES-0549057
Anne Donnelly
University of Florida

SES-0750683
Orlando Taylor
Florence Bonner
Angela Cole
Howard University

The grant provides three years of continued support to the Atlantic Coast Social, Behavioral, and Economic Sciences (AC-SBE) Alliance. AC-SBE, comprised of Howard University, University of Florida (lead institution), University of Maryland at College Park, University of Miami, and University of North Carolina at Chapel Hill, to complete a range of activities with the goal of increasing the number of under-represented minority students receiving doctorate degrees in the social, behavioral, and economic (SBE) sciences and ultimately entering the professoriate. All five universities are currently among the nation's leaders in awarding PhDs in the SBE fields to underrepresented minority students. The AC-SBE Alliance includes elements designed to help students at each step as they move from undergraduate school into graduate programs and onto the professoriate. The Alliance will continue to: (1) recruit and prepare undergraduates to pursue a PhD in SBE fields, (2) assist students in the transition from undergraduate to graduate study, (3) retain PhD students and increase degree completion rates, and (4) prepare future SBE faculty for success. Although each of the five schools in the AC-SBE alliance has unique features, the AC-SBE Alliance includes a number of overarching or "value-added" activities that involve sharing resources across the five universities. For example, the Alliance builds upon Howard University's Summer Institute that prepares future faculty in the STEM (science, engineering and technology) fields, adding a parallel SBE component. Also, entering AC-SBE students participate in a one-week course--Introduction to Data Analysis for the Social Sciences--at the Odum Institute for Research in the Social Sciences at the University of North Carolina at Chapel Hill. The Odum Institute also offers a number of videoconference short courses to AC-SBE students.

Broader Impacts. Through integrating the resources of the five Alliance institutions, AC-SBE has the potential to realize a broad impact across a wide region of the country in the production of SBE PhD recipients. Thus, AC-SBE serves as a comprehensive project for recruiting, mentoring, and graduating underrepresented students in SBE PhD programs, and further to more broadly support students who want to pursue graduate studies and academic careers. It is anticipated that the norms of inclusiveness at the AC-SBE Alliance institutions and the relationships that have been forged will endure well past the termination of grant support to continue efforts to ensure the significant numbers of minority students pursue and receive PhD degrees and enter the professoriate.

Intellectual Merit
This proposal is for the evaluation of a currently-funded NSF program: The AGEP Collaborative Research Training: North Carolina Alliance to Create Opportunity Through Education (OPT-ED). In evaluating the program, the OPT-ED alliance administration and partners seek to accomplish two objectives:
1. Assess the extent to which OPT-ED has been successful in meeting the goals of AGEP and its specific objectives; and
2. Inform the OPT-ED alliance about effective strategies in accomplishing AGEP goals as it moves forward.
As the OPT-ED alliance implements strategies that are designed to increase the enrollment and retention of URM students in STEM disciplines and advance into the professoriate, it is important to assess the impact of each program component and the strategies that are most effective in producing the desired outcomes. Evaluation results are intended to inform OPT-ED alliance partners as they plan future strategies and activities. It is also intended to inform the alliance about additional partners that may be included (e.g., community colleges, early childhood educators, etc.); existing and new resources to tap into; and potentially new concepts to incorporate.
Broader Impact
The OPT-ED alliance strategies are designed to broaden the participation of underrepresented groups; namely, URM doctoral graduates and faculty in STEM fields. The evaluation of OPT-ED seeks to identify those strategies that have proved to be most effective in raising the interest of URM students in STEM majors; retaining them through their college years up to receiving the doctorate degree; and impacting their decision to pursue STEM faculty positions. Successful strategies have the potential for replication across other universities at a national level.
Moreover, the evaluation will serve to assess the extent to which the alliance serves as a model for replication. One of the questions the evaluation seeks to answer is the role each partner plays in enhancing the enrollment and retention of URM students in STEM majors. Evaluation results will identify the most critical type of partners, the type and level of networking and collaboration across partners, and the barriers that must be overcome for implementing a successful alliance.
The national concern over the small presence of URM groups in STEM fields is clearly warranted. The OPT-ED alliance is established to implement strategies and activities that raise URM student interest in STEM disciplines and help them overcome obstacles to their retention until completion of doctoral degrees. This evaluation will identify critical partnerships and successful strategies in enhancing URM student enrollment and retention in STEM majors and careers.

In this doctoral dissertation enhancement project, scanning tunneling microscopy (STM) will be used to examine flurorophillic self assembly as a means to control the morphology of thin films that are grown for use in organic field-effect transistors (OFETs) and organic photovoltaics (OPVs). The doctoral student, Hayden Black, will combine his expertise in synthetic polymer chemistry with the expertise in the modern analytical technique of STM in the laboratory of Prof. Dmitrii Perepichka of McGill University in order to provide insight into morphological control in the fabrication of thin-films of both OFETs and OPVs.

The methods of growing organic semiconductors utilized in these studies may offer transformative pathways to fabricate organic semiconducting devices having improved performance and reliability. These methods might also have a significant impact on the fabrication of organic semiconductor devices in general. The graduate student will benefit greatly from being part of this synergistic international collaboration, which further strengthens the student's ongoing studies of these organic semiconductors. Providing first-rate international research experiences for U.S. students is a major goal of the Office of International Science and Engineering.

ID: MPS/DMR/BMAT(7623) 1206957 PI: Ashby, Valerie ORG: University of North Carolina

Title: Shape Memory Biomaterials Possessing Independent Photo and Thermal Switches for Dual and Triple Shape Memory

INTELLECTUAL MERIT: Shape memory polymers (SMPs) are proving to be an attractive, novel tool in biomedical applications including self-tightening sutures, self-deploying stents, and drug delivery vehicles. The transition in dual SMPs is characterized by a change from shape A to shape B upon direct or indirect triggering typically by heat and more recently by light. Triple shape polymeric materials (TSPs), first developed in 2006, have received increased attention in biomedical research due to their ability to perform complex movements (for example, shape A to B to C). In spite of the unique mobility properties of both systems, there remain significant challenges. Specifically, for dual shape memory polymers in many of the proposed biomaterials applications, the transition temperature (T-trans) should be near body temperature (37 °C). However, because the T-trans is altered by several factors (molecular weight, crosslink density, functionality), it is often challenging to target specific transition temperatures, as any change in either property results in a T-trans shift. Triple shape materials often take advantage of multiphase polymer networks with two phase-separated domains, and therefore two independent transition temperatures. As a result, the transition temperature and property control challenges seen in dual shape memory are even more pronounced in the triple shape system. To address these issues, novel polymeric biomaterials that possess two independent transitions (photo and thermal) within a single temperature range will be designed. For the polymers that possess transitions between room and body temperature, the thermal shape memory properties will be characterized and combined with light-induced shape memory to form unique triple shape materials. Finally, using a modified PRINT (Pattern Replication in Non-Wetting Templates) fabrication method, multi-functional shape memory polymers with the ability to shape shift on the macro and micro/nano scales will be created. To our knowledge, there are no examples of polymeric biomaterials that possess independent thermal and photo switches that can be combined for triple shape memory. At the end of three years these materials will have been developed, their unique properties elucidated and insight gained into their potential as unique multifunctional biomaterials. Potential fields of application include those that require materials capable of complex movement, such as minimally invasive surgery, where multifunctional stents, catheters, and valves could prove to be significant advances in the next generation of smart medical devices.

BROADER IMPACTS: The understanding of shape memory biomaterials will be advanced, while teaching and training will be promoted . Graduate students will learn how to solve problems by starting with polymer design and synthesis and continuing through materials characterization and applications. Undergraduates and high school student researchers will be presented with intriguing, relevant problems that can be answered in the laboratory using organic synthesis, analytical chemistry, and biological techniques. The interdisciplinary interaction will also be an educational opportunity for all students, as they will be active participants in the collaborative research. Additionally, it is expected that the research results will be incorporated, where appropriate, into the teaching of undergraduate organic chemistry and graduate polymer science to help students appreciate the utility of basic concepts. All students will be encouraged to present their research at conferences and publish their research in the appropriate journals. The PI will mentor underrepresented high school, undergraduate and graduate students, as well as junior faculty in various workshops, presentations and research experiences. Finally, the PI will utilize her role as UNC NSF AGEP Director to continue the mentoring of undergraduates interested in pursuing doctoral degrees in STEM fields and graduate students in doctoral programs in STEM fields who are interested in research and teaching careers.

Non-technical summary: Understanding and harnessing the remarkable properties of materials, whether for medicine, energy, or information technology, requires instruments that can accurately probe a material's structure and properties. As technologies advance and materials reduce in size, the tools used to interact with and study materials must also miniaturize. Spectrophotometers, instruments that employ light to probe materials, are essential tools in virtually every area of materials research, and yet the light beams that are emitted from most spectrophotometers are millimeters across rather than micrometers. This project addresses regional and national needs for advanced instrumentation with miniaturized (micro) light beams via the acquisition of a microspectrophotometer. This instrument provides unprecedented capabilities for focusing light into microscopic (less than one micrometer) regions of a material and quantitatively analyzing its structure and properties. This instrument merges five traditionally distinct measurement techniques to yield rich insight into the physical and chemical properties of microstructured and nanostructured materials. This new research capability enables studies with applications that span across multiple areas of research, including 3-D printing, solar cells, and cancer diagnostics. Education of high school, undergraduate and graduate students is advanced through hands-on training and access to the microspectrophotometer. The instrument will be a focal point for classes and training activities for students that explore material properties, surfaces, and light-matter interaction. The location of the instrument in a shared instrument facility with a strong track record of providing broad access enables educational and research activities that positively impact regional universities, government, non-profit users, and industry.

Technical summary: Advancements in research on nanomaterials, biological materials, and their composites are placing increased demands on traditional light-based spectroscopies?especially those that lack the focusing optics needed to resolve nano-to-micrometer scale variations in structure, composition, and properties. The major research instrumention acquired in this project a microspectrophotometer, which combines five traditional spectroscopies into a single platform by using the magnifying optics of a high-powered microscope. The instrument performs transmission, reflection, fluorescence, polarization, and Raman spectroscopies, enabling a single region of a single material to be probed in series by each technique. By employing quartz optics, the usable spectrum extends from 300 nm to 2100 nm, which creates new opportunities to explore small band-gap materials such as those of interest in solar cells and fiber optic communications or to explore label-free detection in cellular diagnostics. The principal objectives of this program are to establish a microspectrophotometer in a shared instrumentation facility in the Chapel Hill Analytical and Nanofabrication Laboratory, to exploit the instrument's capabilities in the fields of electronic and photonic materials, soft matter, and biomaterials, and to use the instrument as a platform for educating a diverse body of students from UNC Chapel Hill and neighboring institutions.

This study will test the hypothesis that awarding of tenure represents an opportunity to nurture innovation as well as non-incremental and novel research pursuits. Development of faculty as highly successful researchers and educators is a critical goal of all universities. Considerable time and effort are invested into recruiting and mentoring exceptionally promising junior faculty. Tenure recognizes the most promising faculty and provides long term security and stability to develop their research ideas. However, less attention is focused upon post-tenure faculty development and the formulaic tenure process in most universities discourages risk associated with pursuing innovative research. This project will test a program to effect a refocusing of research direction in newly tenured faculty, with the goal of increasing their desire and ability to engage with significant problems.

This study seeks to leverage achievement of tenure as a pivot point for inducing reflection, with the goal of stimulating newly tenured faculty to engage with novel research directions with increased potential for societal impact. The study will involve development of a unique, interdisciplinary program, the Faculty Springboard, targeting recently tenured associate professors drawn from the sciences and engineering at Duke University to facilitate the exploration of new and potentially groundbreaking research initiatives. The program will consist of: 1) an annual innovation workshop, focusing on community building, networking and brainstorming; 2) professional coaching and mentoring to further develop faculty?s novel research ideas; 3) a follow-up workshop to cement project development. Program delivery and effectiveness will be assessed through a comprehensive evaluation plan. Best practices will be institutionalized to ameliorate societal impact achieved through faculty research.

The anticipated Broader Impact of this research is the expansion of research programs focused on addressing societal challenges. Through developing a faculty network and skillsets in support of creative risk-taking for innovative research, this professional development model has the potential to enhance researchers? abilities to address "wicked problems". By establishing proof of principle at Duke through targeted iterative evaluation, core essential components critical to success of this model program will be identified and disseminated for adaptation by other universities.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.