SBIR Phase I: Encased Cantilevers for Ultra-Sensitive Force and Mass Sensing in Liquids

这个小企业创新研究（SBIR）第一阶段项目将开发一种新颖的、低成本的制造工艺和一种用于封装原子力显微镜（AFM）悬臂的测试工具。该项目将显著降低制造成本，提高这种革命性的封装悬臂技术的可制造性，使液体AFM实验和生物传感器得到广泛采用。液体AFM探针的市场价值约为5000万美元，而这些探针所带来的新的科学能力可能会产生更大的影响。封闭的悬臂梁将在包括健康、技术、能源和教育在内的各个领域带来重大改善。从蛋白质结构的增强分辨率中获得的知识将导致新的治疗方法和植入物。储能材料的原位成像将推进下一代移动设备、运输和电网存储的电池和超级电容器的工程。表征矿物、碳氢化合物和盐水界面将提高油气采收率。这些封闭的悬臂可能成为低浓度生物标志物检测的有效工具，提供早期预警和预防疾病。最后，新工艺的开发可能为其他微机电（MEMS）器件和应用的器件架构制造提供突破。与在空气中工作相比，AFM在液体中工作的灵敏度要低一个数量级以上，导致分辨率损失和表面性质的识别能力差。这个问题是通过引入工程悬臂梁来解决的，悬臂梁采用疏水外壳，在悬臂梁周围捕获气泡，使谐振器保持干燥。具体的技术目标是通过以下方式降低制造成本：1)用一种创新的平行制造技术取代连续且昂贵的聚焦离子束（FIB）铣削步骤；2)通过制造一个测试平台来半自动表征制造器件的性能。这种新颖的制造工艺将能够选择性地去除多个平行探头的探头顶点处的封装材料，测试平台将为许多悬臂提供频率和质量因子测量。第一阶段的成功完成将导致封装悬臂梁的可扩展制造和表征过程。

This Small Business Innovation Research (SBIR) Phase I project will develop a novel, low-cost fabrication process and a testing tool for encased Atomic Force Microscopy (AFM) cantilevers. The project will lead to a significant reduction in fabrication costs and improvement in manufacturability of this revolutionary encased cantilever technology, enabling widespread adoption for liquid AFM experiments and biosensors. The market for liquid AFM probes alone is approximately $50 million, and the new scientific capabilities enabled by these probes could lead to even greater impact. Encased cantilevers will lead to significant improvements in diverse fields including health, technology, energy, and education. The knowledge gained from enhanced resolution of protein structures will lead to new therapeutics and implants. In-situ imaging of energy storage materials will advance the engineering of batteries and supercapacitors for next generation mobile devices, transportation, and grid storage. Characterization of mineral, hydrocarbon, and brine interfaces will lead to enhanced oil and gas recovery. These encased cantilevers may become effective tools for low-concentration biomarker detection, providing early warnings and preventing disease. Finally, the novel process to be developed may provide breakthroughs in the fabrication of device architectures for other micro-electromechanical (MEMS) devices and applications. AFM operation in liquid has more than an order of magnitude lower sensitivity versus working in air, leading to loss of resolution and inferior discernment of surface properties. This problem is solved by introducing engineered cantilevers which keep the resonator dry using a hydrophobic encasement that traps an air bubble around the cantilever. The specific technical objectives aim to reduce fabrication cost by 1) replacing a serial and expensive Focused Ion Beam (FIB) milling step with an innovative and novel parallel fabrication technique and 2) by fabricating a testing platform to characterize the performance of fabricated devices semi-automatically. The novel fabrication process will enable selective removal of the encasement material at the probe apex of many probes in parallel and the testing platform will provide frequency and quality factor measurements for many cantilevers. Successful completion of Phase I will result in a scalable fabrication and characterization process for encased cantilevers.