Heterogeneous Catalysis (Small Molecule)

My research interests encompass a range of emerging, multidisciplinary topics across soft matter physics, chemistry and bioengineering. The unifying theme across these topics is the design and manipulation of materials (e.g., by acoustic, electric and magnetic fields) to direct their assembly, reconfiguration and locomotion for fundamental and applied research in biomedicine and related areas.

My research interests fall broadly into three main thrusts:

1) Development of advanced microfluidic platforms for processing biofluids. This entails engineering chip-based devices empowered by external fields (e.g., acoustic, magnetic and electric), that can perform multiple useful functions like drive cells into individualized compartments for encapsulation, staining and culturing.

2) Synthesis of silicone particle scaffolds to encapsulate, protect and controllably release drugs. Given the remarkable properties of silicones (e.g., stability, tunability and biocompatibility), I am interested in applying sol-gel techniques to synthesize particles that can biospecifically attach to substrates for field-triggered delivery.

3) Design of reconfigurable active matter that is capable of manipulating materials across scales. In particular, I am interested in the lithographic fabrication of particles with complex shape and patches to enable locomotion when stimulated by external fields to create the next generation of micro-robotic tools and constituents for self-healing materials, as examples.

Teaching Interests:

In college, I learned the definition of a leader is someone who sets noble objectives and pursues those objectives with such intensity, that others cannot help but follow. My perspective of teaching is the same. I believe the most important aspects to teaching are to show genuine excitement, to challenge students to identify important problems and to think critically throughout the discovery process (see my “Teaching and Mentorship” Section below).

Given my background, I am prepared to teach core courses in chemical engineering, including but not limited to, thermodynamics, kinetics, polymer science, colloidal systems and transport phenomena. Having majored in biomedical engineering, minored in materials science and graduated with high distinction, I am also prepared to teach classes in biomedical engineering and materials. Given my research and entrepreneurship experiences, I am also excited about the idea of developing and teaching new courses on advanced topics such as microfluidics, field-based manipulations and entrepreneurship.

Notable Awards:

2016 Dean’s Award for Excellence in Mentoring, Duke University

2015 Exceptional Student Award, ISAC (international award to 1 Ph.D. student/yr.)

2014 NSF Graduate Research Opportunities Worldwide Award (to study in Sweden)

2013 Exceptional Student Award, ISAC

2012 NSF Graduate Research Fellowship

2011 The Raven Society, UVA

2010 Tau Beta Pi Engineering Honor Society

Postdoctoral Projects:

“Reconfigurable assemblies of engineered microcubes and active particles powered by AC electric fields” Under Prof. Orlin D. Velev, Department of Chemical & Biomolecular Engineering, NC State University 2016-2017

“Mondisperse silicone gel particles for the encapsulation and controlled release of hydrophobic drugs” Under Prof. Stefan Zauscher, Department of Mechanical Engineering & Materials Science, Duke University 2016-2017

PhD Dissertation:

“Acoustic and magnetic techniques for the isolation and analysis of cells in microfluidic platforms” Under Prof. Gabriel P. López, Department of Biomedical Engineering, Duke University 2011-2016

Successful Proposals:

• NSF graduate research fellowship; 2012-2015; totaling $138,000
• 3 startup awards for Encapsio LLC (I am the CTO); totaling $71,000
• 10 undergraduate research awards (written with students); totaling $60,200
• 7 travel awards (from NSF, MRS, ACS, ISAC, etc.); totaling $15,450

Proposals Under Review:

• NIH R41EB024472; I am the PI/PD; $224,920

Research Experiences:

During my time in graduate school, I developed expertise in designing, fabricating and operating acoustically powered microfluidic (acoustofluidic) devices. During this time, I engineered such systems to isolate rare cells from blood for templating, staining and analysis as well as assemble anisotropic particles into ordered crystallites.

During my postdoc with the NSF’s Research Triangle MRSEC, I expanded this work to fabricate complex particles that, by virtue of their design, can harvest energy from external fields for active propulsion. Additionally, using assemblies of these particles, I helped develop new classes of reconfigurable materials that can bend and flex on demand in so-called “colloidal origami” that can be used to probe cell stiffness and measure the viscoelastic properties of liquid crystals.

In 2016, I co-founded a company (Encapsio LLC) based on discoveries I made at Duke University. Encapsio is a company that produces monodisperse silicone particles to encapsulate, protect and controllably release active ingredients for skin care. In the last 18 months, we raised over $70,000 to: (i) validate the core technology, (ii) develop a beta prototype of our first product (i.e., a formulation containing retinol-encapsulated microparticles), (iii) file intellectual property through Duke University, (iv) send the prototype to third-party laboratories to conduct human irritation studies and controlled release studies and (v) negotiate an exclusive licensing agreement for the technology.

Teaching and Mentorship Experiences:

As a professor, the ultimate measure of my success will be my students (as outlined below); quality research, publications and intellectual property will be enjoyable byproducts. Therefore, to hone my skills as a mentor and educator, I have tenaciously sought mentorship opportunities.

Over the last six years, I have mentored 21 undergraduate, 3 masters and 4 PhD students. Of these, 15 are female and 9 are in underrepresented or minority groups in STEM. These students are from various educational disciplines (i.e., biology, biomedical engineering, chemical engineering, chemistry, mechanical engineering and physics).

Currently 13 of my past and present mentees have peer-reviewed publications in print, and 9 others have publications that are submitted or are in preparation. Also, many of my mentees have placed in top programs after graduation (e.g., MIT Mechanical Engineering PhD Program, UPenn Medical School, UT Austin Chemical Engineering PhD Program, University of Texas Medical Branch MD/PhD Program).

Mentorship is the best part of my job, and so it is with great satisfaction that my students nominated me to win the 2016 Dean’s Award for Excellence in Mentoring, which is an award granted by Duke to only three students annually: (https://gradschool.duke.edu/about/news/c-wyatt-shields-iv-2016-dean-s-award-winner).

Finally, I developed lectures (e.g., on acoustic and magnetic particle manipulations) and I served as a teaching assistant for two classes at Duke (Biomaterials & Biomechanics in 2013 and 2015, where I gave mini-lectures and oversaw laboratory activities) and at the University of Virginia (Biomedical Engineering: Design & Discovery in 2009 and 2011).

Future Directions:

Early on, I plan to devote my lab to three main areas that enable the study of fundamental science as well as develop engineered systems that are competitive for funding by most of the top funding agencies (e.g., NIH, NSF, DOD, ONR):

First, given the ability of acoustofluidic devices to precisely handle cells and biofluids, I would like to devote a portion of my lab to develop innovative microbioanalytical platforms, e.g., for continuous cell staining and washing, high resolution cell imaging and real-time surface potential evaluation of single cells.

Second, while the Stöber process has existed for half a century, the ability to control the properties of silicone particles for encapsulating drugs remains unexplored. By appending bioactive agents to the surfaces of the particles, it should be possible to design a set of particles that stably attach to skin for topical formulations that last days instead of hours. This advancement could revolutionize the treatment of skin disease by slowly delivering potent drugs with narrow therapeutic windows.

Third, one idea that captivates me is the marriage of active particles (i.e., particles that undergo autonomous locomotion) and biological transport. For this project, I envision is the use of engineered active particles as “cellular jetpacks”, where active particles are lithographically engineered to contain small metallic patches that: (i) present antibodies via thiol chemistry for the biospecific attachment of single cells and (ii) enable particles respond to external fields for their active self-propulsion, which could enable on-chip cell separation and the bottom-up assembly of programmable tissues. This would provide a new way of creating hierarchically organized tissue constructs to enable new fundamental studies on engineered tissues.

Publications (selected from 18 articles and 2 patents):

Han, K; Shields IV, CW; Diwakar, NM; Bharti, B; López, GP; Velev, OD. “Sequence-encoded colloidal origami and microbot assemblies from patchy magnetic cubes,” (Minor revisions at Science Advances).

Wang, PY;* Shields IV, CW;* Zhao, T; Jami, H; López, GP; Kingshott, P. “Rapid self-assembly of shaped microtiles into large, close-packed crystalline monolayers on a solid surface,” Small 2016. 12(2): 1309-1314. *Co-First Author; I.F. = 8.3

Shields IV, CW; Sun, D; Johnson, K; Duval, K; Rodriguez, AV; Gao, L; Dayton, PA; López, GP. “Nucleation and growth synthesis of functional, monodisperse and acoustically programmable particles,” Angewandte Chemie International Edition 2014. 53(31): 8070-8073. *I.F. = 11.7

Shields IV, CW; Johnson, LM; Gao, L; López, GP. “Elastomeric negative acoustic contrast particles for capture, acoustophoretic transport, and confinement of cells in microfluidic systems,” Langmuir 2014. 30(14): 3923-3927.

Shields IV, CW; Zhu, S; Yang, Y; Bharti, B; Liu, J; Yellen, BB; Velev, OD; López, GP. “Field-directed assembly of patchy anisotropic microparticles with defined shape,” Soft Matter 2013. 9(38): 9219-9229.

Reviews:

Shields IV, CW; Reyes, C.; López, GP. “Microfluidic cell sorting: A review of the advances in the separation of cells from debulking to rare cell isolation,” Lab on a Chip 2015. 15(5): 1230-1249. *More than 150 citations