A gas-only bioreactor system maintains stable culture environments and reveals that moderate pH deviations trigger transcriptome-wide responses in human cells cultured in physioxia and physiological buffers

Although pH instability is emerging as a potential driver of changes in cell physiology, pH is still poorly controlled during cell culture and in vitro experiments. Standard procedures include the use of chemicals usually not present in the primary physiological buffering system (CO2/HCO3-), such as acids and bases, to manipulate pH levels. This, however, leads to artifacts that potentially affect scientists’ findings. Here, we propose a novel method for controlling pH levels by relying only on the physiological buffering system. pH was manipulated in a repurposed commercial bioreactor set-up, using a two-sided control loop of CO2 and N2 gas in NaHCO3--buffered medium. This method produces optimal and stable dO2 profiles and tightly maintains pH levels. With this procedure, we analyzed the effects of different pH levels (6.8, 7.0, 7.2, and 7.4) on the performance and transcriptome of the human GM12878 cell line over a 72-hours experiment. Our results showed that inflammation and negativ...

尽管pH不稳定正逐渐成为细胞生理变化的潜在驱动因素，但在细胞培养与体外实验中，pH的调控仍存在显著不足。常规实验流程通常会使用非原生生理缓冲系统（CO₂/HCO₃⁻）成分的化学试剂（如酸、碱）来调节pH值，但这类操作会引入人为假象，进而可能干扰科研人员的实验结论。为此，本研究提出一种仅依托原生生理缓冲系统的pH调控新方法。该方法通过改造后的商业化生物反应器装置，在碳酸氢钠（NaHCO₃）缓冲培养基中，借助CO₂与N₂气体的双向控制回路实现pH调节。此方法可生成最优且稳定的溶氧（dO₂）分布曲线，并实现pH值的精准维持。依托该流程，本研究在72小时的实验周期内，分析了不同pH水平（6.8、7.0、7.2与7.4）对人类GM12878细胞系的生长性能与转录组的影响。本研究结果显示，炎症反应与负向……