Journal: Microsystems & Nanoengineering

Article Title: Modular operation of microfluidic chips for highly parallelized cell culture and liquid dosing via a fluidic circuit board

doi: 10.1038/s41378-020-00216-z

Figure Lengend Snippet: a Live-cell fluorescence images (one image per four chambers) showing an overview of all the chambers after 3 days of culturing GFP-expressing HUVECs. b Live-cell fluorescence image of GFP-expressing HUVECs in chambers 6 and 7. c Fluorescence image of fixed HUVECs with the cell F-actin and nuclei stained with ActinRed and NucBlue, respectively. d HUVECs after seeding and subsequent monolayer formation. The cells were seeded at a high cell density (i) and confluent on day 1 (ii). The monolayer was still intact on day 3 (iii) but began to deteriorate on day 4 (iv). At this point, the medium in the supply vial was replaced. The cells showed signs of recovery on day 5 (v) as the monolayer started to reform. The red dots in (iv) and (v) mark the cells counted in the region of interest. e Cells in ten chambers were counted in regions where the monolayer had deteriorated on day 4 (98 h) and after 16 h of recovery (114 h). The black dots represent the mean cell count, and the error bars represent the standard deviation. The cell number increased by an average of 33% in these areas

Article Snippet: Live-cell images of the GFP-expressing HUVECs (Angio-Proteomie, USA) were taken with an EVOS FL cell imaging system using the GFP filter cube.

Techniques: Fluorescence, Expressing, Staining, Cell Counting, Standard Deviation

Journal: Biofabrication

Article Title: Sheet-based extrusion bioprinting: a new multi-material paradigm providing mid-extrusion micropatterning control for microvascular applications

doi: 10.1088/1758-5090/ad30c8

Figure Lengend Snippet: (A) Fluorescent microscopy on day 1 shows living cells illuminated green around a vacant channel. (B)–(D) Antibody tags label pericytes (hPCs) green and endothelial cells (HUVECs) blue within combined group samples. (B) An entire cell-laden sheet is visible. Cell-laden channels toward the bottom have begun to break off, likely due to 7-day hydrogel degradation accelerated by endpoint immunohistochemical processing reagents. (C) hPCs appear to have seeded with more efficiency than HUVECs, suggesting that interspersing HUVECs within the fugitive ink (‘endothelial seeding method’) before printing was inefficient compared to interspersing cells within the solidifying hydrogel ink. However, both cells are viable while positioned around a vacant channel (D) Side-view of sheet showing visibility of vacant channels that can be hindered from a top-down viewing angle. (E) Cell viability in hydrogel sheets containing both cell types was measured above 90% on both days, although viability in the hPC populations was not measured independently. Viability was lower in the HUVEC-only group, likely attributed to the apparent low-efficiency of the endothelial seeding method. (F) Relative cell numbers were significantly higher in the combined groups, suggesting again that cell numbers were significantly lower in the HUVEC populations due to the inefficient endothelial seeding method, thus contributing to lower HUVEC viability in isolation.

Article Snippet: EndoGRO human umbilical vein endothelial cells (HUVECs) and human brain vascular pericytes (hPCs) were obtained from Millipore Sigma (Burlington, MA, USA) and iXCells Biotechnologies (San Diego, CA, USA) at passage 1 and 2, respectively.

Techniques: Microscopy, Immunohistochemical staining, Isolation