A team of Clemson University and Colorado State University faculty will develop inverted colloidal crystal (ICC) membranes for protein separations through the synthesis and haracterization, molecular modeling, and experimental validation. An aim is to take advantage of the highly uniform and controllable pore size, fully interconnected pores, and large void volume of ICC materials for high speed, high efficiency chromatographic bioseparations. While the structural properties of the ICC membranes will be controlled during synthesis, the PIs will use post-synthesis surface modification tools to tailor the chemistry of the ICC membranes. Molecular modeling will play a critical role in the design process, providing a tool for studying the influence of the surface modifications on membrane charge state, and identifying optimized operating pH conditions in a virtual environment. Intellectual Merit It remains a major challenge to create highly porous membrane materials that have precisely controlled pore sizes and narrow pore-size distributions. Another challenge is to understand through modeling how the physicochemical properties of such a membrane would affect its performance to carry out biological separations. Challenges to overcome include: . Designing, synthesizing, and characterizing highly ordered, functionalized ICC membranes . Characterizing the breakthrough response and separation factors for proteins using ICC membranes . Modeling and visualizing ICC membrane properties and protein breakthrough.
Since ICC membranes have uniform and controllable pore size and a fully interconnected, periodic pore structure, they will find numerous applications in membrane chromatography. ICC membranes could also represent a new generation of microfiltration and ultrafiltration membranes for bioseparations and biomedical separations. Broader Impacts. The program will involve a team of undergraduates as part of the Undergraduate Creative Inquiry (UCI) Program. The UCI program goals are to educate the students in the methods of scientific research and to promote reasoning, ethical judgment, and effective communication skills. UCI researchers will participate in both bench-top and modeling projects and will be trained in the fundamentals of computer modeling, membrane synthesis, and protein separation. The goal of the outreach activities is to incorporate experimentation and simulation as teaching tools through existing programs targeted at middle school students and middle school math and science educators. Through the Paws for Polymers outreach program, we will teach engineering and science concepts to twelve Hispanic middle school students who come to campus 1-2 times per month. A week-long summer camp program for these students will be conducted as part of the Summer Science, Engineering and Architecture series. Selected camp activities will be used in a similar format for Project WISE, a 1-week residential camp for rising 8th grade girls, and Sneak-A-Peek, a 1-week camp for incoming female freshmen who plan on majoring in engineering, math, or science. The proposed research has potential implications for proteomics research. Fractionating the proteome into its constituents is a major research challenge that must be met in order to identify proteins and their functions, with the ultimate goal of diagnosing and treating diseases. The ICC membranes that are developed will lead to highly efficient protein separations with higher productivity than currently used chromatographic methods, as a result of their highly uniform three-dimensional structures.
This multi-campus, basic research program developed a new class of membranes called inverted colloidal crystal (ICC) membranes. These membranes are highly ordered and periodic in structure, and easily tailored for target separations. The research program provided a solution to a major challenge; namely, the creation of highly porous membrane materials that have precisely controlled pore sizes and narrow pore-size distributions, and surface chemistries tailored for target applications. This program provided the research training ground for four PhD graduate students, two postdoctoral scholars and a team of undergraduate students. All students were trained in the scientific method and learned how to plan, develop, execute, and present scientific research. Undergraduates were supervised on a daily basis by graduate students. To assist the graduate students to become more reflective and effective mentors, the PI delivered a mentoring course to 14 graduate students from across the college of engineering and science (including PhD students working on this project). In the course assessment, graduate student mentors reported 'significant gains' in skill level among all mentoring categories. The research team designed and prepared ICC membranes for use in protein separations and particle fractionation. Molecular modeling played a critical role in the design process, providing a tool for studying the influence of the membrane surface modifications on membrane charge state, and identifying optimized operating pH conditions in a virtual environment. Microfiltration membranes were prepared with a range of pore sizes and thicknesses. These membranes were able to fractionate particles by size from bi-disperse particle suspensions. Ultrafiltration membranes also were prepared and modified by a special type of surface-initiated polymerization. ICC membranes were found to have ideal ultrafiltration membrane structures, consisting of high porosity and highly interconnected uniform pores, which enabled size-based separations of polysaccharides. Using surface modification, the team also demonstrated that pore size could be adjusted post-membrane synthesis for a specific separation need. Through a graduate research supplement, the scope of the project was expanded to include the development and testing of macroporous membrane adsorbers for bind-and-elute protein purification. The macroporous membranes yielded high protein binding capacity and unprecedented productivity that was two orders of magnitude higher than commercial, particle-based separation media. These macroporous membranes hold potential for protein capture steps, where high protein binding capacities are needed to realize single-cycle processing of very large scale protein therapeutic batch sizes at high-productivity. To increase the likelihood for societal and economic benefits (impact) from this research, our team disseminated findings in a timely way to potential users. In addition to the seven joint publications, we networked and delivered 21 presentations at conferences and universities. All graduate students and some of the undergraduates made presentations. A total of 12 of the 21 presentations on this work were made by these students. The team also was active in science outreach. The goal of the outreach activities was to incorporate experimentation and simulation as teaching tools through existing programs targeted at middle school students and middle school math and science educators. Our undergraduate research team worked with an all-Hispanic 4-H club comprising almost 100% of 7th grade girls. They developed outreach projects based on their research and tested these projects with the 4-H club students during the semester and during a summer camp.
