IN SITU SAXS STUDY OF SILK FIBER FORMATION IN A MICROFLUIDIC ENVIRONMENT

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 蚕丝是一种在环境友好条件下在体内产生的具有高机械性能的生物高分子材料。为了模拟蚕丝形成的自然过程，必须了解其中涉及的每个参数的影响。我们建立了一个微流控芯片，使我们能够研究蛋白质溶液的离子组成和剪切力施加到它沿着其转化为固体纤维的效果。在这个项目中，我们打算通过小角X射线散射（SAXS）跟踪丝蛋白结构的演变，沿着它在这个X射线透明芯片中的路径。初步结果表明，铜和钙等阳离子触发丝蛋白（丝心蛋白）聚集，但以不同的方式。我们通过单纤维衍射实验发现，在一定条件下，切片中产生的纤维具有天然丝的半结晶结构特征。这些互补的结果是非常有前途的，现在需要在现场SAXS测量，以进一步提高我们的理解的影响，每个参数。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Silk is a biopolymer with high mechanical performances produces in vivo in environment-friendly conditions. In order to mimic the natural process of silk formation, the effect of each parameter involved in it must be understood. We built a microfluidic chip enabling us to study both the effect of ionic composition of the protein solution and shear forces applied to it along its transformation to a solid fiber. In this project, we intend to follow by small-angle x-ray scattering (SAXS), the evolution of the silk protein structure along its pathway in this x-ray transparent chip. Preliminary results showed that cations such as copper and calcium trigger silk protein (fibroin) aggregation but in a different way. We have seen by single-fiber diffraction experiments that in certain conditions, the fiber produced in the chip has a semi-crystalline structure characteristic of natural silk. These complementary results are very promising and in situ SAXS measurements are now required to further improve our comprehension of the effect of each parameter.