An automated high-throughput platform for experimental study of burn injuries - in vitro and ex vivo.

The use of in-vitro and ex-vivo models for the study of burn wound injuries is encouraged to reduce the animal burden in experimental burn research. However, few existing platforms enable the production of reproducible, locally confined thermal injuries at short durations in a high-throughput manner for both in-vitro and ex-vivo models. To address this gap, we established an automated high-throughput burn platform (HTBP) that provided accurate control over burn temperature, exposure time, and pressure application. This platform was built by fabricating an aluminum heat block with 96 pins and positioning a high-resolution actuator below the block. By activating the actuator, 96-well cell culture plates and skin samples were pressed against the heat block's pins. We demonstrated the applicability of the HTBP for studying in-vitro burn injuries by investigating the effects of burn temperature and contact duration on cell viability and migration in human umbilical vein endothelial cells and NIH-3T3 fibroblasts. We showed that higher temperatures and a longer contact duration decreased cellular viability and increased the area of the burn. Moreover, we found that even a short exposure time of 200 msec caused a severe burn wound at 75 °C in a cell monolayer. In addition, we used the HTBP to generate burn injuries at different burn durations in ex-vivo porcine skin and showed that dermis discoloration was present in histologic sections after exposure to 100 °C for a short duration of 500 msec. Our work demonstrates that the HTBP can constitute an important tool for both in-vitro and ex-vivo research of mild and severe burn injuries in a tightly controlled setting and high-throughput manner.

Mesenchymal Stem Cells as a Promising Cell Source for Integration in Novel In Vitro Models.

The human-relevance of an in vitro model is dependent on two main factors-(i) an appropriate human cell source and (ii) a modeling platform that recapitulates human in vivo conditions. Recent years have brought substantial advancements in both these aspects. In particular, mesenchymal stem cells (MSCs) have emerged as a promising cell source, as these cells can differentiate into multiple cell types, yet do not raise the ethical and practical concerns associated with other types of stem cells. In turn, advanced bioengineered in vitro models such as microfluidics, Organs-on-a-Chip, scaffolds, bioprinting and organoids are bringing researchers ever closer to mimicking complex in vivo environments, thereby overcoming some of the limitations of traditional 2D cell cultures. This review covers each of these advancements separately and discusses how the integration of MSCs into novel in vitro platforms may contribute enormously to clinical and fundamental research.