###### Abstract  
In this study, graphene oxide (GO) was coated on the surface of a large-area polystyrene film using spray coating. To analyze the possibility of developing a large-area cell culture vessel from this material, the mechanical properties of the coated surface as well as the cell compatibility and cell proliferation in the vessel were evaluated. Step measurements confirmed a curve of 100 nm or larger on the cell culture vessel surface. The surface was composed of GO (as determined from Raman spectroscopy) and its measured transmittance was ~90% or higher. The coated surface was rendered hydrophilic with an increase in surface energy. Although the cells hardly grew on the general polystyrene film, they attached and proliferated on the polystyrene film coated with GO. Zero cytotoxicity was reported, particularly in the sample that was spray-coated three times at 93.75 mm/s. Note that the cell viability was 1.43 times higher than that in the conventional cell culture vessel. Economic and efficient large-area cell culture vessels can be developed if the GO coating establishes an appropriate surface roughness and surface energy.  
graphene oxide; spray coating; large-area coating; cell culture +
Footnote †: journal: Applied  
biomaterial for biomedical applications, including cell culture plates, biosensors, and more recently, filter materials, that inactivate the COVID-19 virus [11; 12; 13; 14]. The advantages of GO, unlike other metals such as molybdenum and titanium, include non-toxicity, being harmless to the human body, and physicochemical properties similar to metals despite being a nonmetal. In addition, the physical properties of the GO matrix are known to promote the adhesion, proliferation, and differentiation potential of progenitor cells [15; 16]. Previously, our team investigated the characteristics of GO and the development of the coating process to assess the viability of GO as a biomaterial for efficient cell culture vessels [17]. The study confirmed that a GO coating on the plastic cell culture plate induced fast cell attachment and increased cell proliferation efficiency. Moreover, this coating process is rapid, relatively simple, and economic. It demonstrated its potential as a high-efficiency method of producing cell culture plates [18; 19].  
In the previous study, GO was coated on the surface of polystyrene cell-culture vessels with a diameter of 35 mm. The earlier results highlighted the requirement for the deposition of GO on a large area in a cell culture system that must be mass-produced for clinical applications. In order to increase the cell culture efficiency, the cell adhesion time must be reduced, and the proliferation efficiency increased within the economic constraints of mass production. In this study, we developed the GO-coated plate in a large area and investigated its coating properties. The physiochemical analysis was performed with Raman spectroscopy, surface energy analysis, contact angle analysis, and surface transparency [20]. Biological analysis was performed on cell cultures using human fibroblast cells and human bone marrow-derived mesenchymal stem cells, followed by cell viability, cell proliferation analysis, flow cytometry, and enzyme-linked immunosorbent assay (ELISA).