As a consequence of the surplus of glycerol generated from the development of the biodiesel industry, making valuable products from it has been an ongoing subject for the past few years. In previous work, several products have been synthesized from glycerol, such as solketal, with a proven value as an additive to different types of fuels. On the other hand, nhexadecane is frequently used as a reference compound to model diesel properties. This work presents a thorough experimental study on the determination of different volumetric properties of binary mixtures containing n-hexadecane and solketal, namely, density, viscosity, surface tension, refractive index, and the excess properties and deviations thereof derived. These properties were measured over the entire range of compositions in increments of the molar fraction of the components of 0.1 in the range from 293.15 or 298.15 to 323.15 K. Finally, correlation of the Redlich−Kister equation to the experimental excess properties and deviations was made, allowing for the retrieval of the corresponding fitting parameters.

BACKGROUNDHuman mesenchymal stem/stromal cells (hMSCs) are at the forefront of regenerative medicine applications due to their relatively easy isolation and availability in adults, potential to differentiate and to secrete a range of trophic factors that could determine specialised tissue regeneration. To date, hMSCs have been successfully cultured in vitro on substrates such as polystyrene dishes (TCPS) or microcarriers. However, hMSC sub‐cultivation and harvest typically employs proteolytic enzymes that act by cleaving important cell membrane proteins resulting in long‐term cell damage. In a process where the cells themselves are the product, a non‐enzymatic and non‐damaging harvesting approach is desirable.RESULTSAn alternative system for hMSC expansion and subsequent non‐enzymatic harvest was investigated here. A liquid/liquid two‐phase system was proposed, comprising a selected perfluorocarbon (FC40) and growth medium (DMEM). The cells exhibited similar cell morphologies compared with TCPS. Moreover, they retained their identity and differentiation potential post‐expansion and post‐harvest. Further, no significant difference was found when culturing hMSCs in the culture systems prepared with either fresh or recycled FC40 perfluorocarbon.CONCLUSIONSThese findings make the FC40/DMEM system an attractive alternative for traditional cell culture substrates due to their ease of cell recovery and recyclability, the latter impacting on overall process costs. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

BACKGROUND Traditional large‐scale culture systems for human mesenchymal stem/stromal cells (hMSCs) use solid microcarriers as attachment substrates. Although the use of such substrates is advantageous because of the high surface‐to‐volume ratio, cell harvest from the same substrates is a challenge as it requires enzymatic treatment, often combined with agitation. Here, we investigated a two‐phase system for expansion and non‐enzymatic recovery of hMSCs. Perfluorocarbon droplets were dispersed in a protein‐rich growth medium and were used as temporary liquid microcarriers for hMSC culture. RESULTS hMSCs successfully attached to these liquid microcarriers, exhibiting similar morphologies to those cultured on solid ones. Fold increases of 3.03 ± 0.98 (hMSC1) and 3.81 ± 0.29 (hMSC2) were achieved on day 9. However, the maximum expansion folds were recorded on day 4 (4.79 ± 0.47 (hMSC1) and 4.856 ± 0.7 (hMSC2)). This decrease was caused by cell aggregation upon reaching confluency due to the contraction of the interface between the two phases. Cell quality, as assessed by differentiation, cell surface marker expression and clonogenic ability, was retained post expansion on the liquid microcarriers. Cell harvesting was achieved non‐enzymatically in two steps: first by inducing droplet coalescence and then aspirating the interface. Quality characteristics of hMSCs continued to be retained even after inducing droplet coalescence. CONCLUSION The prospect of a temporary microcarrier that can be used to expand cells and then ‘disappear’ for cell release without using proteolytic enzymes is a very exciting one. Here, we have demonstrated that hMSCs can attach and proliferate on these perfluorocarbon liquid microcarriers while, very importantly, retaining their quality.