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

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.