Geometrical Considerations for the Design of Liquid-phase Biochemical Sensors Using a Cantilever\u27s Fundamental In-plane Mode

The influence of the beam geometry on the quality factor and resonance frequency of resonant silicon cantilever beams vibrating in their fundamental in-plane flexural mode in water has been investigated. Compared to cantilevers vibrating in their first out-of-plane flexural mode, utilizing the in-plane mode results in reduced damping and reduced mass loading by the surrounding fluid. Quality factors as high as 86 have been measured in water for cantilevers with a 20 μm thick silicon layer. Based on the experimental data, design guidelines are established for beam dimensions that ensure maximal Q-factors and minimal mass loading by the surrounding fluid, thus improving the limit-of-detection of mass-sensitive biochemical sensors. Elementary theory is also presented to help explain the observed trends. Additional discussion focuses on the tradeoffs that exist in designing liquid-phase biochemical sensors using in-plane cantilevers

Development of Micro-actuators and Micro-sensors for the On-chip Interrogation of Cells and In Vitro Generated Tissues.

Microscale systems enable interrogation of biological mechanisms beyond the capacity of conventional macroscale techniques. The large surface-to-volume ratio of microscale platforms allows investigators to better control the spatial and temporal microenvironment presented to biological samples, manipulating samples at scales reminiscent of their native microenvironments. This research describes microscale technologies to advance the design, complexity, and control of tissue culture microenvironments in three areas – chemical stimulation, regulating cell culture dimensionality, and oxygen monitoring. These tools improve in vitro models to better emulate the native biological response. To regulate temporal patterns of biochemical stimulation I developed an autonomous microfluidic oscillator circuit that enables dynamic control of delivered fluids without external control signals. This work produced to (1) a practical system to modulate the duty cycle of an applied stimulus in a user-defined manner without requiring modification of the device itself; and (2) a method to couple multiple independent oscillators together to ensure uniformity of experimental parameters, such as frequency and duty cycle, across multiple devices. In other work, reproducibility of three-dimensional spheroid cultures was achieved by culture additives to generate increasingly complex, and robust microscale cultures. We also developed dispersible microsensors for tissue culture oxygen measurements. When recreating physiologic microenvironments, it is critical to monitor and quantify the presence of oxygen. The untethered biocompatible oxygen sensors can be embedded or dispersed within diverse culture conditions for the real-time/continuous detection of oxygen in vitro. Dispersible microsensors were used to visualize the oxygen environment within in vitro tumor models, which allow for the informed generation of tumor models to more accurately capitulate the necessary oxygen environments.PhDBiomedical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113506/1/sashacai_1.pd

MEMS Gyroscopes for Consumers and Industrial Applications

none2mixedAntonello, Riccardo; Oboe, RobertoAntonello, Riccardo; Oboe, Robert

OSTEMER polymer as a rapid packaging of electronics and microfluidic system on PCB

[EN] A new heterogeneous integration method is presented that allows the integration of a microfluidic platform and a multi-channel quartz crystal microbalance array on a printed circuit board (PCB) using a dry adhesive bonding method. In this work, the microfluidic platform is a replica molded using a UV-curable OSTEMER 322 Crystal Clear polymer. The OSTEMER acts both as a final package for the cartridge and as a functional material for hosting molded microfluidic channels, the input reservoirs and the waste reservoir. The method is demonstrated by the integration of an array of 24 of a 150 MHz high fundamental frequency quartz crystal microbalance (HFF-QCM) to the OSTEMER microfluidic packaging. The resulting bond interface is shown to be completely homogeneous and void free, and the package is tested to a differential pressure of up to 4 bars. The leak test of the cartridge is performed by pressurizing a microfluidic channel with an aqueous solution using an external peristaltic pump for more than 4 h. The cartridge performance is evaluated by the electrical characterization. Q-factor values of 9507 and of 650are achieved in air and DI water, respectively. Results show that this simple integration method of the HFF-QCM is a promising way to integrate microfluidics into the more complex heterogeneous system.This work was funded by the European Commission Horizon 2020 Programme under the Grant Agreement number ICT-28-2015/687785-LIQBIOPSENS (Reliable Liquid Biopsy technology for early detection of colorectal cancer).El Fissi, L.; Fernández Díaz, R.; García Molla, P.; Calero-Alcarria, MDS.; García Narbón, JV.; Jiménez Jiménez, Y.; Arnau Vives, A.... (2019). OSTEMER polymer as a rapid packaging of electronics and microfluidic system on PCB. Sensors and Actuators A Physical. 285:511-518. https://doi.org/10.1016/j.sna.2018.11.050S51151828

Microsensors Based on MEMS Technology

Sensors play an important role in most of the common activities that occur in our daily lives. They are the building blocks of or microelectromechanical systems (MEMS). This combination of micromechanical structures, sensing elements, and signal conditioning is the beginning of a new era in sensor technology. Sensing systems incorporated with dedicated signal processing functions are called intelligent sensors or smart sensors. The present decade of new millennium will be the decade of smart systems or MEMS. The rapid rise of silicon MEMS recently was due to major advances in silicon microfabrication technology, especially surface micromachining, deep-reactive ion etching, and CMOS-integrated MEMS. In this paper, an overview of the currently available MEMS sensors, materials for sensors and their processing technologies, together with integraticm of sensors and electronics is presented