As 3D printing becomes more common and the technique is used to build culture platforms, it is imperative to develop surface treatments for specific responses. The advantages of aminating and oxidizing polystyrene (PS) for human mesenchymal stem cell (hMSC) proliferation and osteogenic differentiation are investigated. We find that ammonia (NH3) plasma incorporates amines while oxygen plasma adds carbonyl and carboxylate groups. Across 2D, 3D, and 3D dynamic culture, we find that the NH3- treated surfaces encouraged cell proliferation. Our results show that the NH3-treated scaffold was the only treatment allowing dynamic proliferation of hMSCs with little evidence of osteogenic differentiation. With osteogenic media, particularly in 3D culture, we find the NH3 treatment encouraged greater and earlier expression of RUNX2 and ALP. The NH3-treated PS scaffolds support hMSC proliferation without spontaneous osteogenic differentiation in static and dynamic culture. This work provides an opportunity for further investigations into shear profiling and coculture within the developed culture system toward developing a bone marrow niche model.

中文翻译：

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胺化3D打印的聚苯乙烯可保持干细胞增殖和成骨分化。

随着3D打印变得越来越普遍，并且该技术被用于构建培养平台，必须针对特定响应开发表面处理。研究了胺化和氧化聚苯乙烯（PS）对人间充质干细胞（hMSC）增殖和成骨分化的优势。我们发现氨（NH3）等离子体结合了胺，而氧等离子体则增加了羰基和羧酸酯基团。在2D，3D和3D动态文化中，我们发现NH3处理过的表面促进了细胞增殖。我们的结果表明，经NH3处理的支架是唯一允许hMSCs动态增殖而几乎没有成骨分化迹象的治疗方法。使用成骨培养基，尤其是在3D培养中，我们发现NH3处理促进了RUNX2和ALP更大且更早的表达。NH3处理的PS支架在静态和动态培养中支持hMSC增殖，而没有自发的成骨分化。这项工作提供了一个机会，可以进一步研究发达的培养系统中的剪切谱和共培养，以建立骨髓生态位模型。