Human‐induced pluripotent stem cell (hiPSC)‐derived cardiomyocytes have many promising applications, including the regeneration of injured heart muscles, cardiovascular disease modeling, and drug cardiotoxicity screening. Current differentiation protocols yield a heterogeneous cell population that includes pluripotent stem cells and different cardiac subtypes (pacemaking and contractile cells). The ability to purify these cells and obtain well‐defined, controlled cell compositions is important for many downstream applications; however, there is currently no established and reliable method to identify hiPSC‐derived cardiomyocytes and their subtypes. Here, we demonstrate that second harmonic generation (SHG) signals generated directly from the myosin rod bundles can be a label‐free, intrinsic optical marker for identifying hiPSC‐derived cardiomyocytes. A direct correlation between SHG signal intensity and cardiac subtype is observed, with pacemaker‐like cells typically exhibiting ~70% less signal strength than atrial‐ and ventricular‐like cardiomyocytes. These findings suggest that pacemaker‐like cells can be separated from the heterogeneous population by choosing an SHG intensity threshold criteria. This work lays the foundation for developing an SHG‐based high‐throughput flow sorter for purifying hiPSC‐derived cardiomyocytes and their subtypes.

中文翻译：

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用于识别干细胞衍生的心肌细胞亚型的内在、无标记信号

人类诱导多能干细胞 (hiPSC) 衍生的心肌细胞具有许多有前景的应用，包括受损心肌的再生、心血管疾病建模和药物心脏毒性筛选。当前的分化方案产生异质细胞群，其中包括多能干细胞和不同的心脏亚型（起搏细胞和收缩细胞）。纯化这些细胞并获得明确的、受控的细胞组成的能力对于许多下游应用很重要；然而，目前还没有确定的可靠方法来识别 hiPSC 衍生的心肌细胞及其亚型。在这里，我们证明了直接从肌球蛋白棒束生成的二次谐波生成 (SHG) 信号可以是无标签的，用于识别 hiPSC 衍生的心肌细胞的内在光学标记。观察到 SHG 信号强度与心脏亚型之间存在直接相关性，起搏器样细胞的信号强度通常比心房和心室样心肌细胞低约 70%。这些发现表明，通过选择 SHG 强度阈值标准，可以将起搏器样细胞与异质群体分开。这项工作为开发基于 SHG 的高通量流式分选仪用于纯化 hiPSC 衍生的心肌细胞及其亚型奠定了基础。这些发现表明，通过选择 SHG 强度阈值标准，可以将起搏器样细胞与异质群体分开。这项工作为开发基于 SHG 的高通量流式分选仪用于纯化 hiPSC 衍生的心肌细胞及其亚型奠定了基础。这些发现表明，通过选择 SHG 强度阈值标准，可以将起搏器样细胞与异质群体分开。这项工作为开发基于 SHG 的高通量流式分选仪用于纯化 hiPSC 衍生的心肌细胞及其亚型奠定了基础。