Minkyu Kim

Minkyu Kim

Assistant Professor, BIO5 Institute
Assistant Professor, Biomedical / Materials Science Engineer
Assistant Professor, Biomedical Engineering
Member of the Graduate Faculty
Primary Department
Department Affiliations
Contact
(520) 621-6070

Work Summary

Work Summary
Minkyu Kim's research interests are in the areas of biopolymers and biomaterials for advanced national defense and healthcare. He is currently working to develop functional biopolymer materials for the treatment of antimicrobial-resistance diseases and atherosclerosis.

Research Interest

Research Interest
Minkyu Kim, Ph.D., is an Assistant Professor in the Department of Materials Science and Engineering and the Department of Biomedical Engineering at the University of Arizona. He received a M.S. (2006) in Biomedical Engineering and a Ph.D. (2011) in Mechanical engineering and Materials Science at Duke University. During his Ph.D., he worked in the Single-Molecule Force Spectroscopy group led by Prof. Marszalek. He was a postdoc at MIT from 2012 to 2016, and worked in the Bioinspired and Biofunctional Polymers group led by Prof. Olsen. Dr. Kim’s research is focused on the design and development of biopolymer-based functional materials for targeted applications in healthcare and for national defense. Based on his diverse research experiences in the areas of biopolymer nanomechanics, polymer physics and self-assembly, biomolecular engineering and soft materials, his group is currently developing (a) mechanically responsive soft materials that mimic reversible deformability of red blood cell and that can be utilized as targeted drug delivery vehicles for the early treatment of atherosclerosis and (b) nuclear membrane inspired biopolymer materials that selectively filter and neutralize a broad range of bacteria, fungi and viruses for pharmaceutical, food safety, water decontamination and defense applications. In addition to biomaterial development to mitigate atherosclerosis and infectious diseases, Dr. Kim is also interested in addressing how bioinspired design and biosynthesis can be used for the preparation of novel functional materials, how the nanomechanics of folded biopolymers and artificially engineered hyperbranched biopolymer structures can be translated into the mechanics of macromolecular materials that provide new insight into polymer science, and how protein sequences can control parameters that regulate the functional properties of polymeric materials. Lab Website: http://kim.lab.arizona.edu

Publications

Wang, R., Sing, M. K., Avery, R. K., Souza, B. S., Kim, M., & Olsen, B. D. (2016). Classical Challenges in the Physical Chemistry of Polymer Networks and the Design of New Materials. ACCOUNTS OF CHEMICAL RESEARCH, 49(12), 2786-2795.
Ke, C., Loksztejn, A., Jiang, Y., Kim, M., Humeniuk, M., Rabbi, M., & Marszalek, P. E. (2009). Detecting solvent-driven transitions of poly(A) to double-stranded conformations by atomic force microscopy. Biophysical journal, 96(7), 2918-25.

We report the results of direct measurements by atomic force microscopy of solvent-driven structural transitions within polyadenylic acid (poly(A)). Both atomic force microscopy imaging and pulling measurements reveal complex strand arrangements within poly(A) induced by acidic pH conditions, with a clear fraction of double-stranded molecules that increases as pH decreases. Among these complex structures, force spectroscopy identified molecules that, upon stretching, displayed two distinct plateau features in the force-extension curves. These plateaus exhibit transition forces similar to those previously observed in native double-stranded DNA (dsDNA). However, the width of the first plateau in the force-extension curves of poly(A) varies significantly, and on average is shorter than the canonical 70% of initial length corresponding to the B-S transition of dsDNA. Also, similar to findings in dsDNA, stretching and relaxing elasticity profiles of dspoly(A) at forces below the mechanical melting transition overlap but reveal hysteresis when the molecules are stretched above the mechanical melting transition. These results strongly suggest that under acidic pH conditions, poly(A) can form duplexes that are mechanically stable. We hypothesize that under acidic conditions, similar structures may be formed by the cellular poly(A) tails on mRNA.

Callahan, D. J., Liu, W., Li, X., Dreher, M. R., Hassouneh, W., Kim, M., Marszalek, P., & Chilkoti, A. (2012). Triple Stimulus-Responsive Polypeptide Nanoparticles That Enhance Intratumoral Spatial Distribution. NANO LETTERS, 12(4), 2165-2170.
Kim, M., Gkikas, M., Huang, A., Kang, J. W., Suthiwangcharoen, N., Nagarajan, R., & Olsen, B. D. (2014). Enhanced activity and stability of organophosphorus hydrolase via interaction with an amphiphilic polymer. Chemical communications (Cambridge, England), 50(40), 5345-8.

A simple approach to enhancing the activity and stability of organophosphorus hydrolase (OPH) is developed based on interactions between the hydrophobic poly(propylene oxide) (PPO) block of amphiphilic Pluronics and the enzyme. This strategy provides an efficient route to new formulations for decontaminating organophosphate neurotoxins.

Kim, M., Abdi, K., Lee, G., Rabbi, M., Lee, W., Yang, M., Schofield, C. J., Bennett, V., & Marszalek, P. E. (2010). Fast and forceful refolding of stretched alpha-helical solenoid proteins. Biophysical journal, 98(12), 3086-92.

Anfinsen's thermodynamic hypothesis implies that proteins can encode for stretching through reversible loss of structure. However, large in vitro extensions of proteins that occur through a progressive unfolding of their domains typically dissipate a significant amount of energy, and therefore are not thermodynamically reversible. Some coiled-coil proteins have been found to stretch nearly reversibly, although their extension is typically limited to 2.5 times their folded length. Here, we report investigations on the mechanical properties of individual molecules of ankyrin-R, beta-catenin, and clathrin, which are representative examples of over 800 predicted human proteins composed of tightly packed alpha-helical repeats (termed ANK, ARM, or HEAT repeats, respectively) that form spiral-shaped protein domains. Using atomic force spectroscopy, we find that these polypeptides possess unprecedented stretch ratios on the order of 10-15, exceeding that of other proteins studied so far, and their extension and relaxation occurs with minimal energy dissipation. Their sequence-encoded elasticity is governed by stepwise unfolding of small repeats, which upon relaxation of the stretching force rapidly and forcefully refold, minimizing the hysteresis between the stretching and relaxing parts of the cycle. Thus, we identify a new class of proteins that behave as highly reversible nanosprings that have the potential to function as mechanosensors in cells and as building blocks in springy nanostructures. Our physical view of the protein component of cells as being comprised of predominantly inextensible structural elements under tension may need revision to incorporate springs.