Study of oxygen tension variation within live tumor spheroids using microfluidic devices and multi-photon laser scanning microscopy
Journal
RSC Advances
Journal Volume
8
Journal Issue
53
Date Issued
2018
Author(s)
Sarkar, Sreerupa
Peng, Chien-Chung
Kuo, Chiung Wen
Chueh, Di-Yen
Liu, Yuan-Hsuan
Chen, Peilin
Tung, Yi-Chung
Abstract
Three-dimensional cell spheroid culture using microfluidic devices provides a convenient in vitro model for studying tumour spheroid structures and internal microenvironments. Recent studies suggest that oxygen deprived zones inside solid tumors are responsible for stimulating local cytokines and endothelial vasculature proliferation during angiogenesis. In this work, we develop an integrated approach combining microfluidic devices and multi-photon laser scanning microscopy (MPLSM) to study variations in oxygen tension within live spheroids of human osteosarcoma cells. Uniform shaped, size-controlled spheroids are grown and then harvested using a polydimethylsiloxane (PDMS) based microfluidic device. Fluorescence live imaging of the harvested spheroids is performed using MPLSM and a commercially available oxygen sensitive dye, Image-iT Red, to observe the oxygen tension variation within the spheroids and those co-cultured with monolayers of human umbilical vein endothelial cells (HUVECs). Oxygen tension variations are observed within the spheroids with diameters ranging from 90 ± 10 μm to 140 ± 10 μm. The fluorescence images show that the low-oxygenated cores diminish when spheroids are co-cultured with HUVEC monolayers for 6 hours to 8 hours. In the experiments, spheroids subjected to HUVEC conditioned medium treatment and with a cell adherent substrate are also measured and analyzed to study their significance on oxygen tension within the spheroids. The results show that the oxygenation within the spheroids is improved when the spheroids are cultured under those conditions. Our work presents an efficient method to study oxygen tension variation within live tumor spheroids under the influence of endothelial cells and conditioned medium. The method can be exploited for further investigation of tumor oxygen microenvironments during angiogenesis. ? 2018 The Royal Society of Chemistry.
Other Subjects
Cytology; Endothelial cells; Fluidic devices; Fluorescence imaging; Laser applications; Microfluidics; Monolayers; Photons; Polydimethylsiloxane; Silicones; Tumors; Conditioned medium; Human osteosarcoma cells; Human umbilical vein endothelial cells; In-vitro models; Integrated approach; Micro-fluidic devices; Microenvironments; Polydimethylsiloxane PDMS; Oxygen
Type
journal article