In bone tissue engineering, stem cells are known to form inhomogeneous bone-like nodules on a micrometric scale. Herein, micro- and nano-infrared (IR) micro-spectroscopies were used to decipher the chemical composition of the bone-like nodule. Histological and immunohistochemical analyses revealed a cohesive tissue with bone-markers positive cells surrounded by dense mineralized type-I collagen. Micro-IR gathered complementary information indicating a non-mature collagen at the top and periphery and a mature collagen within the nodule. Atomic force microscopy combined to IR (AFM-IR) analyses showed distinct spectra of “cell” and “collagen” rich areas. In contrast to the “cell” area, spectra of “collagen” area revealed the presence of carbohydrate moieties of collagen and/or the presence of glycoproteins. However, it was not possible to determine the collagen maturity, due to strong bands overlapping and/or possible protein orientation effects. Such findings could help developing protocols to allow a reliable characterization of in vitro generated complex bone tissues.

在骨组织工程中，已知干细胞会在微米尺度上形成不均匀的骨样结节。这里，微米和纳米红外（IR）的微光谱被用来解密的骨的化学成分等结核。组织学和免疫组织化学分析显示具有骨标志物阳性细胞的粘性组织被密集的矿化的I型胶原蛋白包围。Micro-IR收集到的补充信息表明顶部和周边的胶原蛋白未成熟，结节内的胶原蛋白成熟。原子力显微镜结合IR（AFM-IR）分析显示出“细胞”和“胶原”丰富区域的独特光谱。与“细胞”区域相反，“胶原”区域的光谱显示胶原蛋白的碳水化合物部分的存在和/或糖蛋白的存在。但是，由于强条带重叠和/或可能的蛋白质取向作用，无法确定胶原蛋白的成熟度。这些发现可能有助于制定方案，以实现可靠的体外表征 产生复杂的骨组织。