Bach Institute of Biochemistry, Federal Research Center of Biotechnology of the RAS, 119071 Moscow, Russia.
Moscow Institute of Physics and Technology (National Research University), 141700 Dolgoprudny, Russia.
Int J Mol Sci. 2022 Aug 29;23(17):9823. doi: 10.3390/ijms23179823.
Laser-induced forward transfer (LIFT) is a useful technique for bioprinting using gel-embedded cells. However, little is known about the stresses experienced by cells during LIFT. This paper theoretically and experimentally explores the levels of laser pulse irradiation and pulsed heating experienced by yeast cells during LIFT. It has been found that only 5% of the cells in the gel layer adjacent to the absorbing Ti film should be significantly heated for fractions of microseconds, which was confirmed by the fact that a corresponding population of cells died during LIFT. This was accompanied by the near-complete dimming of intracellular green fluorescent protein, also observed in response to heat shock. It is shown that microorganisms in the gel layer experience laser irradiation with an energy density of ~0.1-6 J/cm. This level of irradiation had no effect on yeast on its own. We conclude that in a wide range of laser fluences, bioprinting kills only a minority of the cell population. Importantly, we detected a previously unobserved change in membrane permeability in viable cells. Our data provide a wider perspective on the effects of LIFT-based bioprinting on living organisms and might provide new uses for the procedure based on its effects on cell permeability.
激光诱导正向传输（LIFT）是一种使用凝胶嵌入细胞进行生物打印的有用技术。然而，人们对细胞在 LIFT 过程中所经历的应力知之甚少。本文从理论和实验两方面探讨了酵母细胞在 LIFT 过程中经历的激光脉冲辐照和脉冲加热水平。研究发现，只有靠近吸收钛膜的凝胶层中的 5%的细胞应该在几微秒的时间内被显著加热，这一事实得到了证实，即有相应数量的细胞在 LIFT 过程中死亡。这伴随着细胞内绿色荧光蛋白的几乎完全变暗，这也可以观察到对热休克的反应。结果表明，凝胶层中的微生物经历了约 0.1-6 J/cm 的激光辐照能量密度。这种辐照水平本身对酵母没有影响。我们得出的结论是，在广泛的激光强度范围内，生物打印只会杀死少数细胞群体。重要的是，我们在存活细胞中检测到了以前未观察到的膜通透性变化。我们的数据为基于 LIFT 的生物打印对生物体的影响提供了更广泛的视角，并可能基于其对细胞通透性的影响为该方法提供新的用途。
