AFM testing of live cells

The mechanical characteristics associated with individual cells can reveal much about what they are and how they function in an organism. While many researchers are interested in how mechanical forces affect cells or how the forces cells exert affect their surrounding environment, the Darling Lab focuses on the intrinsic mechanical properties exhibited by specific cell types in unperturbed and perturbed situations. This “mechanophenotype” serves as a biomarker of sorts and is a secondary indicator of many complex, biological events occurring inside the cell. We have investigated the mechanophenotype of many cell types (1-9), and how these characteristics change in response to environmental stimuli (10-14). We are also studying how “mechanical biomarkers” can be applied to cell sorting/enrichment (15-17). Single-cell elastic and viscoelastic properties are obtained using atomic force microscopy (AFM), which allows for high-resolution force and displacement measurement at extremely small scales. We also use AFM to examine the microscale mechanical properties of cell clusters and engineered or isolated tissues (18-20) to complement a range of biochemical assays to answer hypothesis-driven studies.

  1. Dubay R, Fiering J, Darling EM. (2020) Effect of elastic modulus on inertial displacement of cell-like particles in microchannels. Biomicrofluidics. PMCID: PMC7402708. DOI: 10.1063/5.0017770
  2. González-Cruz RD, Dahl KN, Darling EM. (2018) The Emerging Role of Lamin C as an Important LMNA Isoform in Mechanophenotype. Frontiers Cell Devel Biol. 6:151. PMCID PMC6224339.
  3. Labriola NR, Azagury A, Gutierrez R, Mathiowitz E, Darling EM. (2018) Concise Review: Fabrication, customization, and application of cell mimicking microparticles in stem cell science. Stem Cell Transl Med. (7):232-240. PMCID: PMC5788880
  4. González-Cruz RD, Sadick JS, Fonseca VC, Darling EM. (2018) Nuclear lamin protein C is linked to lineage-specific, whole-cell mechanical properties. Cell Mol Bioeng. 11(2):131-142. PMCID: PMC5943047
  5. Shah MK, Garcia-Pak IH,Darling EM. (2017) Influence of inherent mechanophenotype on competitive cellular adherence. Ann Biomed Eng. 45(8): 2036-2047. PMCID: PMC5529242
  6. Yang X, Darling EM, Herzog W. (2017) Functional Properties of Chondrocytes and Articular Cartilage using Optical Imaging to Scanning Probe Microscopy. J Orthop Res. PMCID: PMC5839958
  7.  Darling EM, Di Carlo D. (2015) High-throughput assessment of cellular mechanical properties. Ann Rev Biomed Eng. Volume 17. PMID: 26194428
  8. Kanthilal M, Darling EM. Characterization of mechanical and regenerative properties of human, adipose stromal cells. Cell Mol Bioeng. 2014 Dec;7(4):585-597. PubMed PMID: 25484990; PubMed Central PMCID: PMC4255916.
  9. Toyjanova J, Hannen E, Bar-Kochba E, Darling EM, Henann DL, Franck C. 3D Viscoelastic traction force microscopy. Soft Matter. 2014 Oct 28;10(40):8095-106. PubMed PMID: 25170569; PubMed Central PMCID: PMC4176508.
  10. Darling EM. Force scanning: a rapid, high-resolution approach for spatial mechanical property mapping. Nanotechnology. 2011 Apr 29;22(17):175707. PubMed PMID: 21411911; PubMed Central PMCID: PMC3150532.
  11. Darling EM, Zauscher S, Guilak F. Viscoelastic properties of zonal articular chondrocytes measured by atomic force microscopy. Osteoarthritis Cartilage. 2006 Jun;14(6):571-9. PubMed PMID: 16478668.
  12. Darling EM, Zauscher S, Block JA, Guilak F. (2007) A thin-layer model for viscoelastic, stress-relaxation testing of cells using atomic force microscopy:  Do cell properties reflect metastatic potential? Biophys J. 92 pp. 1784-1791. PMCID: PMC1796808
  13. Darling EM, Topel M, Zauscher S, Vail TP, Guilak F. (2008) Viscoelastic properties of human mesenchymally-derived stem cells and primary osteoblasts, chondrocytes, and adipocytes. J Biomech. 41 (2) pp. 454-464. PMCID: PMC2897251
  14. López-Fagundo C, Livi LL, Ramchal T, Darling EM*, Hoffman-Kim D*. (2016) A biomimetic synthetic feeder layer supports the proliferation and self-renewal of mouse embryonic stem cells. Acta Biomater. NIHMSID: 789354. *Co-corresponding author.
  15. Labriola NR, Darling EM. Temporal heterogeneity in single-cell gene expression and mechanical properties during adipogenic differentiation. J Biomech. 2015 Apr 13;48(6):1058-66. PubMed PMID: 25683518; PubMed Central PMCID: PMC4380682.
  16. Darling EM, Pritchett PE, Evans BA, Superfine R, Zauscher S, Guilak F. (2009) Mechanical properties and gene expression of chondrocytes on micropatterned substrates following dedifferentiation in monolayer. Cell Molec Bioeng. 2 (3) pp. 395-404. PMCID: PMC2898162
  17. Yim EKF, Darling EM, Kulangara K, Guilak F, Leong KW. (2010) Nanotopography-induced changes in focal adhesions, cytoskeletal organization, and mechanical properties of human mesenchymal stem cells. Biomaterials. 31 (2010) pp. 1299-1306. PMCID: PMC2813896
  18. Gilchrist CL, Darling EM, Chen J, Setton LA. (2011) Extracellular matrix ligand and stiffness modulate immature nucleus pulposus cell‐cell interactions. PLoS One. 6 (11) e27170. PMCID: PMC3210142
  19. Darling EM, Di Carlo D. (2015) High-throughput assessment of cellular mechanical properties. Ann Rev Biomed Eng. Volume 17. PMID: 26194428
  20. González-Cruz RD, Fonseca VC, Darling EM. Cellular mechanical properties reflect the differentiation potential of adipose-derived mesenchymal stem cells. Proc Natl Acad Sci U S A. 2012 Jun 12;109(24):E1523-9. PubMed PMID: 22615348; PubMed Central PMCID:PMC3386052.
  21. González-Cruz RD, Darling EM. (2013). Adipose-derived stem cell fate is predicted by cellular mechanical properties. Adipocyte. 2 (2) pp. 87-91. PMCID: PMC3661107
  22. Chen Y, Cossman J, Jayasuriya CT, Li X, Guan Y, Fonseca VC, Yang K, Charbonneau C, Yu H, Kanbe K, Ma P, Darling EM, Chen Q. (2016) Deficient Mechanical Activation of Anabolic Transcripts and Post-Traumatic 1 Cartilage Degeneration in Matrilin-1 Knockout Mice. PLoS ONE.
  23. Dingle YL, Chirila AM, Boutin ME, Livi LL, Labriola NR, Jakubek LM, Morgan JR, Darling EM, Kauer JA, Hoffman-Kim D. (2015) Three-Dimensional Neural Spheroid Culture: An In Vitro Model for Cortical Studies. Tissue Eng C. PMCID: PMC4663656
  24. Coles J, Blum J, Jay G, Darling EM, Guilak F, Zauscher S. (2008) In situ friction measurement on murine cartilage by atomic force microscopy. J Biomech. 41 (3) pp. 541-548. PMCID: PMC2274896