About

Ching-Hwa Kiang is an Associate Professor of Physics & Astronomy and Bioengineering at Rice University. He completed his B.S. at National Taiwan University, earned his Ph.D. from the California Institute of Technology, and conducted postdoctoral research at the Massachusetts Institute of Technology. Throughout his career, he has been recognized for his contributions to the field, including being named a Fellow of the American Physical Society in 2010 and receiving the Best of Small Tech Researcher of the Year award in 2007. He also held the position of Cram Teacher-Scholar at the University of California, Los Angeles from 1996 to 1999 and was awarded the Student Thesis Fellowship by IBM Corporation from 1992 to 1995.

Research topics

• Chemistry
• Biology
• Biochemistry
• Biophysics
• Materials science
• Nanotechnology
• Composite material
• Medicine
• Internal medicine
• Biomedical engineering
• Cancer research

Selected publications

• Observing Dynamic States of Single-Molecule DNA and Proteins Using Atomic Force Microscope

  Cambridge University Press eBooks · 2022-05-05

  book-chapterSenior author

  Biomolecules and biopolymers undergo conformational transitions during many biological processes. For example, some proteins are observed to have multiple intermediate states in the folding/unfolding pathways (Stigler et al., 2011; Yu et al., 2012); intrinsically disordered proteins can form diverse metastable structures (Neupane et al., 2014); functional proteins can often be switched between active and inactive states through conformational transitions (Yang et al., 2003; Hanson et al., 2007; Wijeratne et al., 2013); nucleosomes are able to regulate DNA unwrapping through their conformational transitions (Ngo et al., 2015). These dynamic states of DNA and proteins control their biological functions. Since force plays a fundamental role in many, if not all, biological systems, one way to reveal the dynamics of the molecules is to elucidate its intra- and intermolecular force, which can be used as a marker to capture information about their conformational changes.

  PublisherDOI

• Quantifying the Effect of Anti-cancer Compound (Piperlongumine) on Cancer Cells Using Single-Cell Force Spectroscopy

  bioRxiv (Cold Spring Harbor Laboratory) · 2021 · 1 citations

  Senior authorCorresponding
  • Biophysics
  • Chemistry
  • Materials science

  Abstract Natural compounds have shown a great potential in anti-cancer research by tumor growth inhibition and anti-metastatic properties. Piperlongumine (PL) is a natural compound derived from pepper species that has been demonstrated to have anti-cancer effect on HeLa cells. Here we focus on understanding the mechanical properties of HeLa cells under PL treatment, using Atomic Force Microscopy (AFM) based single-cell manipulation technique. We used AFM to pull single HeLa cells and acquired the force-distance curves that presented stepwise patterns. We analyzed the step force (SF) and observed that cells treated with PL exhibit higher force compared to control cells. This SF increase was also observed in experiments performed on substrates of different stiffness. Therefore, analyzing SF, it is possible to investigate the effect of PL on the mechanical properties of the HeLa cells. The understanding of the PL action on HeLa cells’ mechanical properties may help in the development of effective therapeutic drugs against cancers.

  PublisherOA PDFDOI

• Dependence of Membrane Tether Strength on Substrate Rigidity Probed by Single-Cell Force Spectroscopy

  The Journal of Physical Chemistry Letters · 2020 · 5 citations

  Senior authorCorresponding
  • Materials science
  • Biophysics
  • Chemistry

  Substrate rigidity modulates cell mechanics, which affect cell migration and proliferation. Quantifying the effects of substrate rigidity on cancer cell mechanics requires a quantifiable parameter that can be measured for individual cells, as well as a substrate platform with rigidity being the only variable. Here we used single-cell force spectroscopy to pull cancer cells on substrates varying only in rigidity, and extracted a parameter from the force-distance curves to be used to quantify the properties of membrane tethers. Our results showed that tether force increases with substrate rigidity until it reaches its asymptotic limit. The variations are similar for all three cancer cell lines studied, and the largest change occurs in the rigidity regions of softer tissues, indicating a universal response of cancer cell elasticity to substrate rigidity.

  PublisherDOI

• Mechanical Responses of Breast Cancer Cells to Substrates of Varying Stiffness Revealed by Single-Cell Measurements

  The Journal of Physical Chemistry Letters · 2020 · 22 citations

  • Materials science
  • Biophysics
  • Biomedical engineering

  How cancer cells respond to different mechanical environments remains elusive. Here, we investigated the tension in single focal adhesions of MDA-MB-231 (metastatic breast cancer cells) and MCF-10A (normal human breast cells) cells on substrates of varying stiffness using single-cell measurements. Tension measurements in single focal adhesions using an improved FRET-based tension sensor showed that the tension in focal adhesions of MDA-MB-231 cells increased on stiffer substrates while the tension in MCF-10A cells exhibited no apparent change against the substrate stiffness. Viscoelasticity measurements using magnetic tweezers showed that the power-law exponent of MDA-MB-231 cells decreased on stiffer substrates whereas MCF-10A cells had similar exponents throughout the whole stiffness, indicating that MDA-MB-231 cells change their viscoelasticity on stiffer substrates. Such changes in tension in focal adhesions and viscoelasticity against the substrate stiffness represent an adaptability of cancer cells in mechanical environments, which can facilitate the metastasis of cancer cells to different tissues.

  PublisherOA PDFDOI

• Different Mechanical Responses to Substrate Stiffness between Cancer Cells and Normal Cells

  Biophysical Journal · 2020-02-01

  articleOpen access
  PublisherOA PDFDOI

• Quantifying Substrate Rigidity Effects on Cancer Cell Mechanics using Single Cell Force Spectroscopy

  Biophysical Journal · 2020-02-01

  articleOpen accessSenior author
  PublisherOA PDFDOI

• Mechanical Responses of Cancer Cells to Different Matrices Measured by AFM and FRET

  Biophysical Journal · 2019-02-01

  articleOpen access
  PublisherOA PDFDOI

• The Conformation of Factor H Determines its Von Willebrand Factor Reductase Activity

  Bulletin of the American Physical Society · 2018-03-05

  articleSenior author
  Publisher

• Correlating Conformational Dynamics with the Von Willebrand Factor Reductase Activity of Factor H Using Single Molecule Force Measurements

  The Journal of Physical Chemistry B · 2018-10-10 · 1 citations

  articleSenior authorCorresponding

  Activation of proteins often involves conformational transitions, and these switches are often difficult to characterize in multidomain proteins. Full-length factor H (FH), consisting of 20 small consensus repeat domains (150 kD), is a complement control protein that regulates the activity of the alternative complement pathway. Different preparations of FH can also reduce the disulfide bonds linking large Von Willebrand factor (VWF) multimers into smaller, less adhesive forms. In contrast, commercially available purified FH (pFH) has little or no VWF reductase activity unless the pFH is chemically modified by either ethylenediaminetetraacetic acid (EDTA) or urea. We used atomic force microscopy single molecule force measurements to investigate different forms of FH, including recombinant FH and pFH, in the presence or absence of EDTA and urea, and to correlate the conformational changes to its activities. We found that the FH conformation depends on the method used for sample preparation, which affects the VWF reductase activity of FH.

  PublisherDOI

• Detecting the Biopolymer Behavior of Graphene Nanoribbons in Aqueous Solution

  Bulletin of the American Physical Society · 2017-03-13

  articleSenior author
  Publisher

Recent grants

• Nonequilibrium, Single-Molecule Studies of Protein Unfolding

  NSF · $300k · 2005–2009

• Shear-Activated Molecular Glue

  NSF · $390k · 2009–2013

• NIH Grant R03AG015626

  NIH · $76k · 2001

Frequent coauthors

• Nolan C. Harris

  30 shared

• J. Salem

  University of Nevada, Las Vegas

  22 shared

• Donald S. Bethune

  IBM Research - Almaden

  21 shared

• P. H. M. van Loosdrecht

  University of Cologne

  18 shared

• Sithara S. Wijeratne

  Massachusetts General Hospital

  18 shared

• R. Beyers

  Skadden Arps Slate Meagher & Flom

  18 shared

• P. Burbank

  Virginia Tech

  18 shared

• Harry C. Dorn

  Virginia Tech

  17 shared

Education

• PhD

  California Institute of Technology

  1995

Awards & honors

• Fellow, American Physical Society (2010)
• The Best of Small Tech Researcher of the Year award (2007)
• Cram Teacher-Scholar, University of California, Los Angeles…
• Student Thesis Fellowship, IBM Corporation (1992-1995)