SGER: Laser-Guided Direct Writing of Multipotent Adult Stem Cells

0092810 Odde光学力提供了一种非接触操纵微观粒子的方法，但它们在微细加工和工程应用中的全部潜力尚未实现。 一个可能的原因是，使用光学陷阱的微制造是繁琐的，需要重复的颗粒捕获和沉积在表面上的循环。 另一种方法是使用激光引导直接写入，这是由主要研究者和Mike Renn博士（Optomec设计公司）发明的一种技术，使用弱聚焦激光束来产生沿光束轴沿着光学引导的稳定颗粒流。 当光束被引导朝向目标表面时，光学引导的颗粒沉积在表面上，每个颗粒堆积在先前沉积的颗粒的顶部上。 通过相对于目标表面平移射束轴，稳定的粒子线被有效地“写入”在表面上。 这个过程被称为激光引导直接写入（LGDW），主要研究者和Renn博士已经使用它来光学存款广泛的材料，包括电子材料，光学材料，和活细胞的颗粒大小范围从100纳米到10毫米。这种新的制造微制造技术现在被应用于微电子制造由雷恩博士和合作，在Optomec设计公司工作。 然而，LGDW同样可以很好地应用于生物技术，本项目将使用LGDW来解决组织工程中的关键问题。组织工程的一个主要目标是在体外重建具有天然器官特征的多种细胞类型的良好定义的三维组织，这反过来又倾向于促进工程化器官等效物中更天然的功能。 然而，目前没有可用的方法允许具有单细胞定位精度的多种细胞类型的任意三维图案化。 基于主要研究者和Renn博士最近的工作，其中约100个胚胎鸡脊髓细胞的任意二维图案直接写在玻璃基板上，LGDW似乎具有这种能力。 与此同时，干细胞在组织工程应用中的应用也取得了快速进展。 在明尼苏达大学，Catherine Verfaillie教授（医学系）开发了一种分离多能成体干细胞（MASC）的方法。 这些骨髓来源的细胞然后分化成广泛的细胞类型，包括肌肉细胞、神经元、上皮细胞和内皮细胞。 此外，这些细胞来源于人类，因此不需要动物或人类胚胎/胎儿组织。 有效开发这种应用的关键问题是在细胞培养环境中适当的空间和时间诱导分化。 特别地，为了实现工程化组织所需的功能，将有必要重现天然组织结构。 为了开发一种微制造方法来实现这一目标，拟议的研究将调查使用LGDW进行MASC的二维图案化，并确定MASC的活力作为波长，强度和用于图案化的曝光持续时间的函数。 这些研究将探索LGDW的应用超出目前的微电子应用，包括干细胞技术，生物医学研究的最有前途的领域之一。

0092810OddeOptical forces provide a means of noncontact manipulation of microscopic particles, but their full potential in microfabrication and engineering applications has not been realized. A likely reason is that microfabrication with an optical trap is tedious, requiring repeated cycles of particle capture and deposition on a surface. An alternative approach is to user laser-guided direct writing, a technique invented by the principal investigator and Dr. Mike Renn (Optomec Design Company) that uses a weakly focused laser beam to generate a steady flow of particles that are optically guided along the beam axis. When the beam is directed toward a target surface, the optically guided particles are deposited on the surface with each particle piling on top of the previously deposited ones. By translating the beam axis relative to the target surface, a steady line of particles is effectively "written" on the surface. This process, called laser-guided direct writing (LGDW), has been used by the principal investigator and Dr. Renn to optically deposit a wide range of materials including electronic materials, optical materials, and living cells with particle sizes ranging from 100 nm to 10 mm. This novel fabrication microfabrication technique is now being applied to microelectronics fabrication by Dr. Renn and co-works at Optomec Design Company. However, LGDW can be equally well applied to biotechnology an this project will use LGDW to address key issues in tissue engineering.A major objective of tissue engineering is to reconstitute in vitro the well-defined three-dimensional organization of multiple cell types that is characteristic of native organs, which in turn tends to promote more native-like function in engineered organ equivalents. However, no method currently available permits arbitrary three-dimensional patterning of multiple cell types with single cell positioning precision. Based on the recent work of the principal investigator and Dr. Renn where arbitrary two-dimensional patterns of ~100 embryonic chick spinal cord cells were directly written on glass substrates, it appears that LGDW has this capability. At the same time, rapid advances are being made in the use of stem cells for tissue engineering applications. At the University of Minnesota, Professor Catherine Verfaillie (Department of Medicine) has developed a procedure for isolating multipotent adult stem cells (MASCs). These bone marrow-derived cells are then differentiated into a wide range of cell types including muscle cells, neurons, epithelial cells, and endothelial cells. In addition, these cells are derived from humans, thus obviating the need for animal or human embryonic/fetal tissue. A key issue in effectively developing this application is the proper spatial and temporal induction of differentiation in a cell culture environment. In particular, to achieve the required functions of the engineered tissue, it will be necessary to recapitulate the native tissue architecture. To develop a microfabrication approach to achieve this goal, the proposed research will investigate the use of LGDW for two-dimensional patterning of MASCs and determination of MASC viability after guidance as a function of wavelength, intensity, and duration of exposure used for patterning. These studies will explore the application of LGDW beyond the current microelectronics applications to encompass stem cell technology, one of the most promising areas of biomedical research.