Development of a feed-back controlled culture system to maximize calcification of tissue-engineered hone promoted by strain-induced fluid flow

干细胞具有分化为特定器官细胞的潜力，可以在培养过程中利用合适的支架再生失去的器官。这种被称为组织工程或再生医学的技术是一种很有前途的策略，具有很高的生物相容性，避免了尸体供体移植和活体供体移植的伦理问题。近年来，人们研究和发展了由成骨细胞、支架和模拟基质组成的组织工程骨，但与天然骨相比，在体外获得足够的钙化仍然困难。由于这种低机械相容性，特别是缺乏初始刚度和韧性，组织工程骨不适用于植入负载骨部位。本项目的目的是开发一种反馈控制的培养系统，通过应变诱导流体流动的机械刺激来最大限度地促进组织工程骨的钙化。该培养系统有望在植入前为工程骨提供更好的机械相容性。在这个为期两年的项目（2006-2007）中，开发了该系统的两项基本技术。2006年，研制了一种近红外光无损监测体外钙化的光学装置，利用该装置对I型胶原海绵与大鼠原代培养成骨细胞组成的组织工程骨进行了42天的体外钙化监测。3307年，为了确定机械刺激的初始条件，研制了一种紧凑的光学装置，用于观察机械刺激后工程骨中成骨细胞细胞内钙的浓度变化。这些成果将有助于完成组织工程骨的饲料控制培养系统。

Stem cells have a potential to differentiate to specific organ cells and could be utilized to regenerate a lost organ with an appropriate scaffold in culture. This technology called tissue engineering or regenerative medicine is a promising strategy with a high biocompatibility avoiding the ethical problems in cadaveric donor transplantation and living donor transplantation Tissue-engineered bone composed of osteoblasts, a scaffold, and simulative hums was studied and developed in the past years, however it is still difficult to obtain sufficient calcification in vitro, comparing with natural bones. With this low mechano-compatibility, in particular a shortage of initial stiffness and toughness, tissue-engineered bone is not applicable to implantation to loaded bone sites. The purpose of this project is to development of a feed-back controlled culture system to maximize the calcification of tissue-engineered bone promoted by mechanical stimulation in fain of strain-induced fluid flow. This culture system is expected to provide better mechano-compatibility to an engineered bone before implantation. In this two-year project (2006-2007), two elemental technologies for the system were developed. In 2006, an optical device for non-destructive monitoring of in vitro calcification was developed using near-infrared light Using this device, the calcification of tissue-engineered bone composed of a type I collagen sponge and rat-primary cultured osteoblasts was monitored for 42 days in culture. In 3307, in the purpose of determination of initial condition of mechanical stimulation, a compact optical device was developed to observe concentration changes in intracellular calcium in osteoblasts populated in an engineered bone just after mechanical stimulation. These achievements should contribute to completion of the feed-hack controlled culture system for tissue-engineered bone.