Bae-Yeun Ha

In Professor Ha's research group, they explore a few theoretical problems in soft matter and biophysics, namely, chromosomes in living cells and lipid bilayer membranes.

• Biomaterials, Polymers and Bioplastics
• Biochemistry and Biophysics
• Soft Matter
• Physiology, Cell and Developmental Biology
• Theoretical molecular biophysics & soft matter
• Polymer physics for chromosome organization in a cell
• Confined polymers: chain topology, spatial organization, & dynamics
• Electrostatics in soft matter and biomolecules
• Electrostatic modification of lipid membranes
• Physical basis for cell selectivity of antimicrobial peptides

Chromosomes in living cells are strongly confined but show a high level of spatial organization. Recent experiments suggest that bacterial chromosomes behave as confined polymers and undergo abrupt compaction in a crowed medium. We have been exploring as model chromosomes confined polymers possibly with non-linear topology or cross-linking, and their compaction by crowding particles. For instance, we have shown how cylindrical confinement reshapes individual polymer chains and enhances their segregation, in the way seen in rod-shaped bacteria. Lipid bilayer membranes, enclosing living cells, primarily serve as permeability barriers. As self-assembled structures, however, their permeability and stability can be altered by surrounding ions or molecules (e.g., Mg2+ and antimicrobial peptides). Along this line, lipopolysaccharide (LPS), which carries multiple negative charges, is the key surface component of Gram-negative bacteria, constituting the outer layer of their outer membrane or simply the LPS layer. If Mg2+ stabilizes the (negatively-charged) LPS layer, cationic antimicrobial peptides permeabilize it. Inspired by this long-standing observation, we have been interested in presenting a physical picture of how the LPS layer can be electrostatically modified.

• 1996, Doctorate Physics, University of Maryland, College Park, Maryland, U.S.A.
• 1986, Master of Science Physics, Korea University, Seoul, Korea
• 1985, Bachelor of Science (BS) Physics, Korea University, Seoul, Korea

• Centre for Bioengineering and Biotechnology

• PHYS 225 - Modeling Life Physics
  • Taught in 2019, 2020, 2021, 2022, 2024
• PHYS 242 - Electricity and Magnetism 1
  • Taught in 2022
• PHYS 365 - Mathematical Physics 2
  • Taught in 2019, 2021, 2022
• PHYS 380 - Molecular and Cellular Biophysics
  • Taught in 2022
• PHYS 491 - Special Topics in Life, Medical and Biophysics
  • Taught in 2019, 2022

* Only courses taught in the past 5 years are displayed.

• Bae-Yeun Ha and Youngkyun Jung. "Polymers under confinement: single polymers, how they interact, and as model chromosomes". Soft Matter, 2015, 11, 2333-2352
• Juin Kim, Chanil Jeon, Hawoong Jeong, Youngkyun Jung and Bae-Yeun Ha. "A polymer in a crowded and confined space: effects of crowder size and poly-dispersity". Soft Matter, 2015, 11, 1877-1888
• Chanil Jeon, Juin Kim, Hawoong Jeong, Youngkyun Jung and Bae-Yeun Ha. "Chromosome-like organization of an asymmetrical ring polymer confined in a cylindrical space". Soft Matter, 2015, 11, 8179-8193
• Azadeh Bagheri, Sattar Taheri-Araghi, and Bae-Yeun Ha. "How Cell Concentrations Are Implicated in Cell Selectivity of Antimicrobial Peptides". Langmuir, 2015, 31 (29), pp 8052–8062.
• Please see Pubfacts for a complete list of Dr. Ha's publications.