Biophysical interactions between cell and extracellular matrix (ECM) play an important role in biological processes, including initiation and progression of cancer, stem cell differentiation, morphogenesis, and wound healing. Importantly, cell-ECM interactions have been shown to differ in 2D versus 3D environment, driving the pursuit of cellular-scale studies in the more physiologically relevant 3D engineered cellular systems and biological tissues. However, existing approaches for characterizing ECM mechanical properties are typically limited to bulk mechanical testing or atomic force microscopy (which only probes the 2D surface of the sample). Our lab developed optical elastography techniques based on highly localized mechanical excitation provided by photonic and acoustic forces, and ultra-precise displacement detection by phase-sensitive OCT.
For cellular-scale mechanical microscopy of 3D engineered ECM, photonic force optical coherence elastography (PF-OCE) utilizes force from a weakly-focused laser beam to provide localized mechanical excitation on micro-beads embedded in the samples. Local mechanical properties of the ECM around each embedded bead is reconstructed from the measured bead mechanical responses. For volumetric mechanical characterization of biological tissues, acoustic radiation force optical coherence elastography (ARF-OCE) utilizes force from a focused ultrasound beam to provide localized mechanical excitation on ex vivo tissue specimens or in vivo animal models. Local strain and tissue mechanical properties are reconstructed from the measured tissue deformations.
See our poster on PF-OCE and ARF-OCE here.
- Lin, Y., Leartprapun, N., Adie, S.G., “Spectroscopic photonic force optical coherence elastography,” Opt. Lett. 44, 4897-4900 (2019)
- Leartprapun, N., Lin, Y., Adie, S.G., “Microrheological quantification of viscoelastic properties with photonic force optical coherence elastography,” Opt. Express 27, 22615-22630 (2019)
- Leartprapun, N., Iyer, R.R., Untracht, G.R. et al. Photonic force optical coherence elastography for three-dimensional mechanical microscopy. Nat. Commun. 9, 2079 (2018)
- Leartprapun, N., Iyer, R.R., Adie, S.G. “Depth-resolved measurement of optical radiation-pressure forces with optical coherence tomography,” Opt. Express 26, 2410-2426 (2018)
- Leartprapun, N., Iyer, R.R., Mackey, C.D., Adie, S.G. “Spatial localization of mechanical excitation affects spatial resolution, contrast, and contrast-to-noise ratio in acoustic radiation force optical coherence elastography,” Biomed. Opt. Express 10, 5877-5904 (2019)
- Leartprapun, N., Iyer, R.R., Adie, S.G. “Model-independent quantification of soft tissue viscoelasticity with dynamic optical coherence elastography,” Proc. SPIE 10053, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI, 1005322 (17 February 2017)