Our lab develops imaging technologies and computational image formation techniques based on optical coherence tomography (OCT), a non-invasive and label-free interferometric optical imaging modality, for biological and mechano-biological studies at both cellular and tissue levels.
Our research encompasses three main areas. See a brief description of each research area below and follow the link in the titles for more details.
Cellular traction forces (CTFs) play a role in many physiological and disease processes, including cell migration, cancer metastasis, stem cell differentiation, wound healing, and synapse formation. Traction force microscopy (TFM) is a family of optical techniques used to quantify CTF. Typical methods for 3D TFM are based on confocal fluorescence microscopy, and can suffer from limited penetration depth, slow acquisition speeds, and photobleaching/phototoxicity concerns. Our lab developed traction force optical coherence microscopy (TF-OCM) to overcome these challenges and enable 4D TFM for the study of both single cells and multi-cellular constructs in scattering media.
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.
See our Nature Communications paper on 3D mechanical microscopy with PF-OCE here.
Cellular-resolution high-throughput imaging over an extended volumetric coverage in scattering biological media is desirable for many biological studies. Such capability enables the study of collective (emergent) cellular dynamics in both in vitro engineered biological systems and in vivo models of diseases. However, current optical microscopy techniques suffer from the detrimental effects of optical aberrations and ‘multiple scattering (MS)’ in biological media. Our lab has developed computed optical coherence microscopy (OCM) methods to enable geometrically accurate (distortion-free) volumetric OCM reconstructions that are computationally corrected for defocus and optical aberrations. Combining both hardware and computational approaches, we introduced hybrid adaptive optics (hyAO) to overcome the effects of MS in biological media, and increase the volumetric throughput of OCM. Leveraging computed OCM, we are also developing a multimodal hyAO approach to enable faster and deeper volumetric OCM and three-photon microscopy.
See our Editor’s Pick Biomedical Optics Express paper on hyAO-enabled high-throughput volumetric OCM here.