Cell therapy manufacturing is limited by lack of online tools capable of realtime in-process monitoring, particularly of simultaneous changes in multiple orthogonal (mutually independent) parameters. Here, we studied changes in CD36 expression, number density and size (area) of erythroblasts through different stages of erythropoiesis in vitro using a quartz crystal resonator (QCR), integrated with a microscope, and flow cytometry in parallel. An analytical model was developed extending the Kanazawa-Gordon theory. Based on this model, independent correlations were established between changes in each QCR parameter, dissipation ($\Delta \text{Γ}$) and resonance frequency ($-\text{Δ}{f}_0$), and CD36 expression (from flow cytometry) and cell area (from microscope). The correlation functions were used to derive an acoustic signature ($-\Delta \text{Γ}/\text{Δ}{f}_0$) of the differentiation process that uniquely mapped the relative changes in CD36 expression and late-stage enucleation-related deviations. A method to quantify relative changes in cell area purely from the acoustic parameters was also proposed. This work demonstrated for the first time the potential of an electromechanical tool for online monitoring of concurrently varying orthogonal phenotypic parameters in cell therapy manufacturing.

细胞疗法的制造受到缺乏能够进行实时过程内监测的在线工具的限制，特别是多个正交（相互独立）参数的同时变化。在这里，我们使用石英晶体谐振器（QCR），显微镜和流式细胞仪，研究了体外通过不同阶段的红细胞生成过程，CD36表达，成色细胞数量密度和大小（面积）的变化。建立了扩展金泽-戈登理论的分析模型。基于此模型，在每个QCR参数的变化，耗散（$\Delta \text{Γ}$）和共振频率（$-\text{Δ}{F}_0$），CD36表达（来自流式细胞仪）和细胞面积（来自显微镜）。相关函数用于导出声学特征（$-\Delta \text{Γ}/\text{Δ}{F}_0$）的分化过程，该过程独特地映射了CD36表达的相对变化和后期摘除相关的偏差。还提出了一种仅根据声学参数来量化细胞面积相对变化的方法。这项工作首次证明了用于在线监测细胞疗法生产中同时变化的正交表型参数的机电工具的潜力。