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Chun Min Lo

Bio: Chun Min Lo is an academic researcher from National Yang-Ming University. The author has contributed to research in topics: Electric cell-substrate impedance sensing & Digital holographic microscopy. The author has an hindex of 20, co-authored 36 publications receiving 5385 citations. Previous affiliations of Chun Min Lo include University of South Florida & Rensselaer Polytechnic Institute.

Papers
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Journal ArticleDOI
TL;DR: It is discovered that changes in tissue rigidity and strain could play an important controlling role in a number of normal and pathological processes involving cell locomotion, including morphogenesis, the immune response, and wound healing.

3,189 citations

Journal ArticleDOI
TL;DR: Techniques of digital holography are improved in order to obtain high-resolution, high-fidelity images of quantitative phase-contrast microscopy, and the angular spectrum method of calculating holographic optical field is seen to have significant advantages including tight control of spurious noise components.
Abstract: Techniques of digital holography are improved in order to obtain high-resolution, high-fidelity images of quantitative phase-contrast microscopy. In particular, the angular spectrum method of calculating holographic optical field is seen to have significant advantages including tight control of spurious noise components. Holographic phase images are obtained with 0.5 μm diffraction-limited lateral resolution and largely immune from the coherent noise common in other holographic techniques. The phase profile is accurate to about 30 nm of optical thickness. Images of SKOV-3 ovarian cancer cells display intracellular and intranuclear organelles with clarity and quantitative accuracy.

651 citations

Journal ArticleDOI
TL;DR: Transepithelial impedance of Madin-Darby canine kidney cell layers is measured by a new instrumental method, referred to as electric cell-substrate impedance sensing, and shows that reduction of Ca2+ concentration causes junction resistance between cells to drop and the distance between the basal cell surface and substratum to increase.

284 citations

Journal ArticleDOI
TL;DR: The results suggest that myosin IIB is involved not in propelling but in directing the cell movement, by coordinating protrusive activities and stabilizing the cell polarity.
Abstract: Although myosin II is known to play an important role in cell migration, little is known about its specific functions. We have addressed the function of one of the isoforms of myosin II, myosin IIB, by analyzing the movement and mechanical characteristics of fibroblasts where this protein has been ablated by gene disruption. Myosin IIB null cells displayed multiple unstable and disorganized protrusions, although they were still able to generate a large fraction of traction forces when cultured on flexible polyacrylamide substrates. However, the traction forces were highly disorganized relative to the direction of cell migration. Analysis of cell migration patterns indicated an increase in speed and decrease in persistence, which were likely responsible for the defects in directional movements as demonstrated with Boyden chambers. In addition, unlike control cells, mutant cells failed to respond to mechanical signals such as compressing forces and changes in substrate rigidity. Immunofluorescence staining indicated that myosin IIB was localized preferentially along stress fibers in the interior region of the cell. Our results suggest that myosin IIB is involved not in propelling but in directing the cell movement, by coordinating protrusive activities and stabilizing the cell polarity.

239 citations

Book ChapterDOI
TL;DR: A powerful tool for the study of mechanical interactions between cells and their physical environment, this method will be particularly useful for studying the functions of various components at focal adhesions, and the effects of mechanical forces on focal adhesion-mediated signal transduction.
Abstract: We have described a powerful tool for the study of mechanical interactions between cells and their physical environment. Although the approach has already been used in a variety of ways to measure traction forces and to characterize active and passive responses of cultured cells to mechanical stimulation, it can be extended easily and combined with other microscopic approaches, including fluorescent analog imaging (Beningo et al., 2001), photobleaching, calcium imaging, micromanipulation, and electrophysiology. This method will be particularly useful for studying the functions of various components at focal adhesions, and the effects of mechanical forces on focal adhesion-mediated signal transduction. In addition, the method can be extended to a 3D setting, e.g., by sandwiching cultured cells between two layers of polyacrylamide to create an environment mimicking that in the tissue of a multicellular organism. Whereas chemical interactions between cells and the environment have been investigated extensively, many important questions remain as to the role of physical forces in cellular functions and the interplay between chemical and physical mechanisms of communication. The present approach, as well as other approaches capable of probing physical interactions, should fill in this important gap in the near future.

174 citations


Cited by
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Journal ArticleDOI
25 Aug 2006-Cell
TL;DR: Naive mesenchymal stem cells are shown here to specify lineage and commit to phenotypes with extreme sensitivity to tissue-level elasticity, consistent with the elasticity-insensitive commitment of differentiated cell types.

12,204 citations

Journal ArticleDOI
18 Nov 2005-Science
TL;DR: An understanding of how tissue cells—including fibroblasts, myocytes, neurons, and other cell types—sense matrix stiffness is just emerging with quantitative studies of cells adhering to gels with which elasticity can be tuned to approximate that of tissues.
Abstract: Normal tissue cells are generally not viable when suspended in a fluid and are therefore said to be anchorage dependent. Such cells must adhere to a solid, but a solid can be as rigid as glass or softer than a baby's skin. The behavior of some cells on soft materials is characteristic of important phenotypes; for example, cell growth on soft agar gels is used to identify cancer cells. However, an understanding of how tissue cells-including fibroblasts, myocytes, neurons, and other cell types-sense matrix stiffness is just emerging with quantitative studies of cells adhering to gels (or to other cells) with which elasticity can be tuned to approximate that of tissues. Key roles in molecular pathways are played by adhesion complexes and the actinmyosin cytoskeleton, whose contractile forces are transmitted through transcellular structures. The feedback of local matrix stiffness on cell state likely has important implications for development, differentiation, disease, and regeneration.

5,889 citations

Journal ArticleDOI
TL;DR: It is found that tumors are rigid because they have a stiff stroma and elevated Rho-dependent cytoskeletal tension that drives focal adhesions, disrupts adherens junctions, perturbs tissue polarity, enhances growth, and hinders lumen formation.

3,553 citations

Journal ArticleDOI
25 Nov 2009-Cell
TL;DR: Reduction of lysyl oxidase-mediated collagen crosslinking prevented MMTV-Neu-induced fibrosis, decreased focal adhesions and PI3K activity, impeded malignancy, and lowered tumor incidence, and data show how collagenCrosslinking can modulate tissue fibrosis and stiffness to force focal adhesion, growth factor signaling and breast malignancies.

3,396 citations

Journal ArticleDOI
26 Jun 2009-Science
TL;DR: Multifaceted technologies are increasingly required to produce and interrogate cells ex vivo, to build predictive models, and, ultimately, to enhance stem cell integration in vivo for therapeutic benefit.
Abstract: Stem cell fate is influenced by a number of factors and interactions that require robust control for safe and effective regeneration of functional tissue. Coordinated interactions with soluble factors, other cells, and extracellular matrices define a local biochemical and mechanical niche with complex and dynamic regulation that stem cells sense. Decellularized tissue matrices and synthetic polymer niches are being used in the clinic, and they are also beginning to clarify fundamental aspects of how stem cells contribute to homeostasis and repair, for example, at sites of fibrosis. Multifaceted technologies are increasingly required to produce and interrogate cells ex vivo, to build predictive models, and, ultimately, to enhance stem cell integration in vivo for therapeutic benefit.

2,446 citations