“…Similarly, the presence of tissue-specific ECM has been shown to facilitate cell phenotype maintenance in vitro ( Pei et al, 2011 ; Cheng et al, 2014 ; Gattazzo et al, 2014 ; Yang et al, 2018a ). In eukaryotic cell culture systems, macromolecular crowding (MMC), following the principles of excluded volume effect, enhances and accelerates tissue-specific ECM deposition ( Raghunath and Zeugolis, 2021 ; Tsiapalis and Zeugolis, 2021 ; Zeugolis, 2021 ), a phenomenon that has been well documented in both differentiated ( Lareu et al, 2007 ; Satyam et al, 2014 ; Kumar et al, 2015a ; Kumar et al, 2015b ; Satyam et al, 2016 ; Kumar et al, 2018 ; Gaspar et al, 2019 ; Shendi et al, 2019 ; Tsiapalis et al, 2021 ) and progenitor cell cultures ( Zeiger et al, 2012 ; Prewitz et al, 2015 ; Cigognini et al, 2016 ; Lee et al, 2016 ; Patrikoski et al, 2017 ; Graceffa and Zeugolis, 2019 ; De Pieri et al, 2020 ). However, to-date, only one study has assessed the influence of MMC in xeno-free and/or serum-free media formulations using human adipose-derived mesenchymal stromal cells ( Patrikoski et al, 2017 ).…”