In Vitro Monitoring of a Cultured Human Retinal Pigment Epithelium Using 1375-nm Spectral-Domain Optical Coherence Tomography

Abstract

Measurement of cell number is important in cell-based in vitro screenings for therapeutic drugs and tissue engineering such as cell culture maintenance, cell plating, and cell growth, as well as monitoring of cell viability, proliferation, and cytotoxicity. We performed cell counting using intensity-based in vitro spectral domain optical coherence tomography (SD-OCT). Adult retinal pigment epithelium cells were cultured on a glass dish to prevent diffuse reflection from the surface, and the dish was tilted by 15° during OCT imaging to reduce coherence noise from specular reflection. Rasterized scanning was performed to generate a 3D volume image with an en face image of the retinal pigment epithelium cell layers. Cell counting was achieved by measuring the density of bright spots after layer extraction and thresholding. Two other cell counting methods were also performed for the purpose of comparison, one using a hemocytometer and the other using water-soluble tetrazolium-1 (WST-1); cell counting by in vitro OCT yielded results better than those from the hemocytometer. Our results showed that in vitro OCT systems can be a powerful tool for estimating and analyzing cell density in a cultured sample without the need for dyeing the sample or causing cell death.

Editorial: Advances in Optics and Acoustics Towards Translational Functional Neuroimaging

“…Also, in PET and fMRI, the expansion into interventional guidance has been prevented other than diagnostics, due to no flexibility in system configuration. Conventional optical imaging has offered high temporal resolution, but have limited dynamic ranges and cover only superficial tissue depths, often requiring invasive craniotomy with problematic long-term consequences abandoning translational practicality to non-human primate and to human studies (Kim et al, 2017 ; Han and Cha, 2020b ; Tayebi et al, 2020 ).…”