University of North Carolina, Chapel Hill and North Carolina State University, Joint Department of Biomedical Engineering, Raleigh, North Carolina 27695, USA.
Appl Spectrosc. 2010 Nov;64(11):1227-33. doi: 10.1366/000370210793335106.
Methods capable of nondestructively collecting high-quality, real-time chemical information from living human stem cells are of increasing importance given the escalating relevance of stem cells in therapeutic and regenerative medicines. Raman spectroscopy is one such technique that can nondestructively collect real-time chemical information. Living cells uptake gold nanoparticles and transport these particles through an endosomal pathway. Once inside the endosome, nanoparticles aggregate into clusters that give rise to large spectroscopic enhancements that can be used to elucidate local chemical environments through the use of surface-enhanced Raman spectroscopy. This report uses 40-nm colloidal gold nanoparticles to create volumes of surface-enhanced Raman scattering (SERS) within living human-adipose-derived adult stem cells enabling molecular information to be monitored. We exploit this method to spectroscopically observe chemical changes that occur during the adipogenic differentiation of human-adipose-derived stem cells over a period of 22 days. It is shown that intracellular SERS is able to detect the production of lipids as little as one day after the onset of adipogenesis and that a complex interplay between lipids, proteins, and chemical messengers can be observed shortly thereafter. After 22 days of differentiation, the cells show visible and spectroscopic indications of completed adipogenesis yet still share spectral features common to the progenitor stem cells.
鉴于干细胞在治疗和再生医学中的重要性日益增加，能够从活体人类干细胞中无损地收集高质量、实时化学信息的方法变得越来越重要。拉曼光谱是一种可以无损地实时收集化学信息的技术。活细胞摄取金纳米粒子，并通过内体途径运输这些粒子。一旦进入内体，纳米粒子聚集形成簇，产生大的光谱增强，可通过使用表面增强拉曼光谱来阐明局部化学环境。本报告使用 40nm 胶体金纳米粒子在活体人脂肪来源成体干细胞内创建表面增强拉曼散射（SERS）体积，从而能够监测分子信息。我们利用这种方法在人脂肪来源干细胞向脂肪细胞分化的 22 天内，通过光谱学观察到发生的化学变化。结果表明，在脂肪生成开始后仅一天，细胞内 SERS 就能够检测到脂质的产生，并且此后不久就可以观察到脂质、蛋白质和化学信使之间的复杂相互作用。经过 22 天的分化，细胞表现出明显的和光谱学上的脂肪生成完成的迹象，但仍具有祖细胞干细胞的共同光谱特征。
