STTR Phase I: Development of a Novel Mass/Heat Flow Sensor for an Accurate Nanobalance

该小型企业技术转让（STTR）第一阶段研究项目将包括设计，制造和测试新的质量和热流传感器的原型，该传感器将允许在纳克和亚纳克水平上精确测量固体，液体和吸收气体。多功能和准确的质量传感器的开发将使商业仪器的后续开发能够定量确定固体，液体，残留物和吸收/吸附气体的质量小于一纳克（纳米天平），并监测质量变化和其他性能在与气体反应期间或作为温度，湿度和其他环境因素的函数（纳米天平/微量热计）。目前商业分析天平的灵敏度被限制在1微克以上，本项目的目标是通过改变电极的尺寸和形状，并通过对电极表面进行物理和/或化学修饰，将液体（如含有感兴趣的分析物的一滴溶液）限制在恒定质量灵敏度的区域，来开发传感器。经过重新设计的石英晶体谐振器将使分析天平的灵敏度提高至少两个数量级，特别是对于天平市场中增长最快的微量天平。它还将极大地扩展材料类型和纳克量的同时重量/量热分析的应用。具有巨大商业利益的一个应用是“液滴重力仪”的创建，这是一种测量一滴溶液中总溶解固体浓度的新技术。将测定质量的溶剂蒸发至干燥后，液滴重量分析仪将以百万分之一的精度测量溶液的非挥发性残留物。对于其他溶解性差但有价值的材料，如合成蛋白质或DNA片段，目前的限制排除了常规使用重量分析法，需要其他不太直接和更复杂的方法来确定溶解度。

This Small Business Technology Transfer (STTR) Phase I research project will encompass the design, fabrication and testing of prototypes for a new mass and heat flow transducer that would permit accurate measurements of solids, liquids and absorbed gases at nanogram and sub-nanogram levels. The development of a versatile and accurate mass sensor will enable the subsequent development of commercial instruments with the capabilities to quantitatively determine masses of solids, liquids, residues and absorbed/ adsorbed gases to less than one nanogram (nanobalance) and monitor mass changes and other properties during reactions with gases or as a function of temperature, humidity and other environmental factors (nanobalance /microcalorimeter). The sensitivity of commercial analytical balances is presently limited to greater than one micro-gram. The goal of this project is to develop a sensor by modifying the size and shape of the electrodes and by confining liquids, such as a drop of solution containing an analyte of interest, to a region of constant mass sensitivity by physical and/or chemical modifications of the electrode surface. The resulting sensor would enable nanogram measurements on a broad range of materials.The redesigned quartz crystal resonator will increase sensitivity for analytical balances by at least two orders of magnitude, particularly for micro-balances, the fastest growing segment of the balance market. It will also greatly expand the types of materials and applications for simultaneous gravimetric/calorimetric analysis in nanogram quantities. One application of great commercial interest is the creation of a "droplet gravimeter", a new technique which measures the concentration of total dissolved solids in a drop of solution. The droplet gravimeter will measure the nonvolatile residue of the solution with parts-per-million precision after the solvent of determined mass is evaporated to dryness. For other poorly soluble but valuable materials such as synthetic proteins or DNA fragments, current limitations preclude using gravimetry routinely, and other less direct and more complex methods are required to determine solubility.