SIGNIFICANCE Research in tissue engineering and in vitro organ formation has recently intensified. To assess tissue morphology, the method of choice today is restricted primarily to histology. Thus novel tools are required to enable noninvasive, and preferably label-free, three-dimensional imaging that is more compatible with futuristic organ-on-a-chip models. AIM We investigate the potential for using multiphoton microscopy (MPM) as a label-free in vitro approach to monitor calcium-induced epidermal differentiation. APPROACH In vitro epidermis was cultured at the air-liquid interface in varying calcium concentrations. Morphology and tissue architecture were investigated using MPM based on visualizing cellular autofluorescence. RESULTS Distinct morphologies corresponding to epidermal differentiation were observed. In addition, Ca2  +  -induced effects could be distinguished based on the architectural differences in stratification in the tissue cultures. CONCLUSIONS Our study shows that MPM based on cellular autofluorescence enables visualization of Ca2  +  -induced differentiation in epidermal skin models in vitro. The technique has potential to be further adapted as a noninvasive, label-free, and real-time tool to monitor tissue regeneration and organ formation in vitro.

中文翻译：

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使用多光子显微镜在体外监测钙诱导的表皮分化。

意义 组织工程和体外器官形成方面的研究最近得到了加强。为了评估组织形态，今天选择的方法主要限于组织学。因此，需要新的工具来实现与未来器官芯片模型更兼容的无创、最好是无标记的三维成像。目的 我们研究了使用多光子显微镜 (MPM) 作为一种无标记的体外方法来监测钙诱导的表皮分化的潜力。方法 体外表皮在气液界面以不同的钙浓度培养。使用基于可视化细胞自发荧光的 MPM 研究形态学和组织结构。结果 观察到对应于表皮分化的不同形态。此外，基于组织培养中分层的结构差异，可以区分 Ca2+ 诱导的效应。结论 我们的研究表明，基于细胞自发荧光的 MPM 能够在体外表皮皮肤模型中观察 Ca2+ 诱导的分化。该技术有可能被进一步调整为无创、无标记和实时工具，以监测体外组织再生和器官形成。