# Engineering Resilience: How Irradiation Strategies Influence 3D-Bioprinted Adipose Stem Cells

## TL;DR

This study shows that 3D-printed fat stem cells remain viable after moderate radiation, which could help in tissue repair after radiation therapy.

## Contribution

The study demonstrates the radioresistance of 3D-cultured adipose-derived stem cells under moderate irradiation.

## Key findings

- 3D-printed ASCs showed high cell survival after 24 hours of irradiation.
- HIF-1α expression was 1.5 times higher in the 2 Gy group compared to the control.
- No significant differences in metabolic activity or survival were observed between groups at all timepoints.

## Abstract

Background: Reconstructive defect coverage after irradiation remains a challenge in reconstructive surgery, as ionizing radiation leads to tissue ischemia and fibrosis. Therefore, the application of adipose-derived stem cells (ASCs) might be a therapeutic strategy for improving flap survival. Nevertheless, the influence of irradiation on ASCs remains unclear. This study examines the effect of irradiation on 3D-printed ASCs. Methods: ASCs were 3D-cultured. The constructs were irradiated with 2 Gy and 5 Gy; one group treated with 0 Gy served as the non-irradiated control group. Cell viability was measured via a WST-8 assay, a live/dead assay and fluorescence microscopy 24 h, 48 h and 72 h after irradiation. Furthermore, qPCR analysis was performed to detect the expression of HIF-1α, p53 and IL-6 at the same timepoints. Results: Cell survival was high after 24 h. Expression of HIF1α after 24 h was 1.5 times significantly higher in the 2 Gy group compared with the 0 Gy group. The expression of other genes was not significantly affected by irradiation. Measurement of the metabolic activity and survival of the ASCs did not show differences between the different groups at all timepoints. Conclusions: 3D-cultured adipose-derived stem cells maintain high viability after moderate irradiation, suggesting radioresistance.