<div>With an eye towards applications such as the selective sensing of volatile organic compounds (VOCs) or micro-scale thrust generation, inkjet printing was explored as a means to selectively deposit functional materials. The work detailed herein explores a series of fundamental steps to gain expertise related to the piezoelectric inkjet printing of functional materials. The successful printing of nanothermite was demonstrated with two unique printing techniques. Furthermore, the integration of this material with an ignition mechanism was shown to create a fully printed igniter energetic system. These advancements support future work related to the printing of other energetic materials necessary to create tunable reactive systems. This knowledge was then translated into the development of resonant mass sensing devices that are selectively functionalized using inkjet printing. This approach to functionalization allowed for the precise deposition of receptive chemistries on devices resulting in selective, highly-sensitive devices that successfully detected biomarkers secreted after traumatic brain injuries and harmful VOCs. This work implemented oscillator-based sensors to achieve a low-cost, low-power sensor platform with redundant elements. Furthermore, the predictive capabilities of these devices were explored using least squares and linear regression modeling.</div>

This thesis reports design and implementation of a MEMS based resonant mass sensor for cell detection applications. The main objective of the thesis is the real-time detection of captured cells inside liquid medium and obtaining the detection results by electronic means, without the aid of any external optical instruments. A new resonant mass sensor architecture is presented that has various advantages over its conventional counterparts. The device oscillates in the lateral direction, eliminating squeeze film damping. A thin parylene layer coated on the device prevents liquids from entering the narrow gaps of the device, further improving the quality factor. The resonator is embedded on the floor of a microchannel. A gold film on the proof mass facilitates antibody based cell capture on the device. Theoretical background regarding resonator operation is investigated. Various resonator designs are presented, taking into account design trade-offs, application v considerations, and fabrication limitations. The design procedure is verified with MATLAB Simulink modeling results and finite element simulations. A new process flow has been developed for resonator fabrication, combining SOI, glass, and polymer micromachining. Modifications have been done on the flow for the solution of problems encountered during device fabrication. Each device has a foot print area of 1.5 x 0.5 cm2. The majority of this area is occupied by fluidic connections and reservoirs. Resonance characterization results in air and water have shown that there is significant quality factor enhancement with the parylene coating method. The quality factor decreases to only 170 in water from 610 in air, when the resonator is coated with a thin layer of parylene. Uniformity and linearity tests revealed that the devices have a standard deviation of only 1.9% for different analyte capture sites and an R2 of 0.997 for mass loads as high as 2.7 ng. Detection of Saccharomyces cerevisiae type yeast cells has been done using the resonators. Mass measurement of single yeast cell (13 pg) and yeast clusters (102 pg) have been performed. Antibody and thiol-gold chemistry based Candida Albicans type bacteria capture and detection has also been made in both air and water environments. The mass of several captured bacterial cells in air has been measured as 95pg. Two bacterial cells have been captured on one device inside water and their mass has been measured as 85 pg. It is worthy to note that all mass measurements are consistent with theoretical expectations.

The field of coupled resonant systems is a rich research area with enumerable real-world applications, including the fields of neural computing and pattern recognition, energy harvesting, and even modeling the behavior of certain types of biological systems. This work is primarily focused on the study of the behaviors of two subsets of this field: large networks of globally coupled resonators (which, in this work, refers to passive, damped resonant elements which require external stimulus) and smaller networks of oscillators (referring to active devices capable of self-sustained motion), which are coupled through a network of light-sensitive resistive elements. In the case of the former, we begin by developing an analytical and experimental framework to examine the behaviors of this system under various conditions, such as different coupling modalities and element-level parametric mistunings. Once a proper understanding of the dynamics of these systems has been established, we go on to develop the system into a single-input, single-output, multi-analyte volatile organic compound sensor. For the study of oscillator networks, we begin by building a device which utilizes a network of Colpitts oscillators, coupled through a series of color-filtered CdSe photocells. We then establish that through the analysis of particular emergent behaviors (most notably, frequency locking within the network), this type of system may show promise as a threshold color sensor. By exploiting these behaviors, this type of system may find applications in neuromorphic computing (particularly in optical pattern recognition).