Full-field optical coherence microscopy for identifying live cancer cells by quantitative measurement of refractive index distribution

Abstract

The feasibility of identifying cancer cells by measuring the refractive index (RI) distribution across a single live cell with ultrahigh resolution full-field optical coherence microscopy (FF-OCM) is presented. The FF-OCM is utilized to quantify integral RI distributions of unmodified cells without any cell treatments and used as a biophysical indicator for diagnosing cell malignancy. Firstly, the physical thickness distribution of the cell adherent to a culture dish is measured by taking a series of 0.6 µm resolved en-face tomograms. Subsequently, from the en-face image of the bottom surface of the cell or the top surface of the dish, the phase gain image of the cell is extracted. Then, from these two measurements the axially averaged RI map of the cell is extracted. The implemented FF-OCM system had a 0.8 µm axial resolution and the phase measurement sensitivity of the system was around 124 mrad. With the system, RI maps of several living cell lines of normal and cancer cells were constructed and quantitatively analyzed. The experiments showed that cancer cells had higher RI than normal ones. This approach using the FF-OCM has significant potential for cancer diagnosis and dynamic cell analysis as in situ label-free biophysical assay.

Full-depth epidermis tomography using a Mirau-based full-field optical coherence tomography

“…On this application, axial resolution better than 1.2 μm in tissue is the doorsill to measure LPs of the SC [4]. Besides, the morphology of single 3-D epidermal cell is also important for early detection of normal and abnormal cells of pre-cancer diagnosis [5]. These all require submicron spatial resolution in tissue [6].…”

Qualitative investigation of fresh human scalp hair with full-field optical coherence tomography

“…The potential of FF-OCT for subcellular level imaging in various fields has been demonstrated. 32,33 With the FF-OCT, in this study we capture a series of en-face tomographic images of cut hair shafts and plucked hair bulbs with a depth step of 0.5 μm. In particular, we qualitatively reveal that density of melanin granule in the cortex region would be a dominant factor to determine hair color intensity.…”

Counterfeit Detection Using Characterization of Safety Feature on Banknote with Full-field Optical Coherence Tomography

“…It is thought that the reappearance of the character in Fig. 5(f) and 5(g) is due to the large refractive index of the printing material [7]. At the interface between the bottom of the character and the top surface of the film, the light is reflected and gives a signal, but the image location is appreciably shifted due to the refractive index of the printing material.…”

“…Further, high transverse (XY) resolution is also possible with the configuration of high numerical aperture (NA) microscope objectives. Such characteristics of FF-OCT have offered enhanced contrasts for microscopic structural identification in wide variety of fields, from medical biology [5], clinical pathology [6] and cell biology [7] to even the material industry [8]. Recent application of the scheme has been expanded to biometric-based forensic science in which FF-OCT using a swept laser source has been demonstrated for fingerprint authentication [9].…”