Development of a micromechanical thermogravimetric tool for investigation of biominerals

生物矿物是开发新材料的灵感来源，因为它们具有独特的特性，分层组织和混合组成（有机-无机复合材料）。这种被捕获的材料在确定其固有特性方面起着重要作用。因此，必须测量有机化合物的确切含量和分布，并进一步与给定的特定性质（例如机械）相关联。然而，这些测量受到数量/尺寸约束的限制，即，mm-cm和/或>50 mg，并使用经典的热重分析。本项目旨在开发和实施一种热重分析方法，该方法能够分析质量小至1 ng的微型物体的有机含量，质量分辨率为1 pg。直接分析微尺寸的，单独选择的对象将使我们能够消除与批量分析相关的工件。这种分析技术是基于一个共振加热的微结构（悬臂梁），在共振频率的变化，将使我们能够量化温度引起的质量变化（1 pg）。在方法建立后，合成和天然碳酸钙基生物矿物将被用作概念验证。将揭示有机质含量及其分布（由扫描力显微镜测定）之间的相关性。此外，我们的目标是开发以下目标：a）通过用生物分子功能化微器件可加热尖端并促进CaCO 3直接结晶到微器件上来原位监测结晶过程（质量负载测定）。此外，还将进行有机物含量的本地测定; B）与我们的合作伙伴一起开发定制的高性能微型器件，该器件具有高Q因子分辨率、均匀的温度分布和定义的样品平台（Rao教授，印度理工学院）; c）在可加热的微型器件上进行原位红外吸收测量，以直接监测晶体相变（无定形-结晶）与有机物的影响无关（Thundat教授，加拿大阿尔伯塔大学）。

Biominerals are a source of inspiration for the development of new materials given their unique properties, hierarchical organization and hybrid composition (organic-inorganic composites). This trapped material plays an important role in determining its intrinsic properties. Thus, both the exact content and the distribution of organic compounds must be measured and further correlated to given specific property (e.g. mechanical). However, these measurements are limited by quantity/size constrains, i.e., mm-cm and/or >50 mg and to the use of classical thermogravimetric analysis. This project aims to develop and implement a thermogravimetric analysis capable of analyzing the organic content micro-sized objects with masses as small as 1 ng with mass resolution of 1pg. The direct analysis of microsized, individually selected objects will allow us to eliminate artifacts associated with bulk analysis. This analytic technique is based on a resonating heated microstructure (cantilever) that, upon resonance frequency shifts, will allow us to quantify temperature-induced mass changes (1pg). Upon methodology establishment, both synthetic and natural CaCO3-based biominerals will be used as proof-of-concept. A correlation between organic mass content and its distribution (determined by scanning force microscopy) will be revealed. Further, we aim to develop the following goals: a) in situ monitoring of crystallographic processes (mass loading determination) by functionalizing the microdevices heatable tips with biomolecules and promoting CaCO3 direct crystallization onto the microdevice. In addition local determination of organic content will be performed; b) development of a custom-made high performance microdevices with high Q-factors resolution, a uniform temperature distribution and a defined sample platform together with our cooperation partner (Prof. Rao, IIT, India); c) implementation of in situ IR-absorption measurements carried out on heatable microdevices for direct monitoring of crystal phase-transitions (amorphous-crystalline) not associated with an organic influence (Prof. Thundat, University Alberta, Canada).