Effects of COVID-19 on a CMOS fabrication course: An integrated design experience.

In the CMOS fabrication course described herein, the lecture component provides the theoretical background for semiconductor materials and integrated circuit fabrication processes. The laboratory component provides the hands-on experience required to fabricate and electrically characterize CMOS circuits in a one-semester format. A strong semiconductor device process design thread is achieved in the course by integrating the laboratory experience and process simulation/modeling and theoretical calculations.

Six-stage cascade paramagnetic mode magnetophoretic separation system for human blood samples.

This paper is focused on the development of a six-stage cascade paramagnetic mode magnetophoretic separation (PMMS) system for separating suspended cells in blood based on their native magnetic properties. The design and fabrication of a PMMS system are presented and the microfluidic separation system is characterized experimentally using human whole blood as the case study. The PMMS system can separate blood cells types continuously using the magnetophoretic force produced from a high magnetic field gradient without magnetic or fluorescent tagging.

Lateral displacement as a function of particle size using a piecewise curved planar interdigitated electrode array.

We describe the lateral displacement of a particle passing over a planar interdigitated electrode array at an angle as a function of the particle size. The lateral displacement was also measured as a function of the angle between the electrode and the direction of flow. A simplified line charge model was used for numerically estimating the lateral displacement of fluorescent polystyrene (PS) beads with three different diameters.

An automated micro-solid phase extraction device involving integrated \high-pressure microvalves for genetic sample preparation.

This paper presents an automated micro-SPE device for DNA extraction using monolithically integrated high-pressure microvalves. The automated micro-SPE device was fabricated through glass-to-glass thermal bonding and microfluidic system interface technologies. To increase the DNA extraction efficiency, silica beads were packed in the extraction microchannel involving two weir structures.

Lateral-driven continuous dielectrophoretic microseparators for blood cells suspended in a highly conductive medium.

This paper presents lateral-driven continuous dielectrophoretic (DEP) microseparators for separating red and white blood cells suspended in highly conductive dilute whole blood. The continuous microseparators enable the separation of blood cells based on the lateral DEP force generated by a planar interdigitated electrode array placed at an angle to the direction of flow. The simplified line charge model that we developed for the theoretical analysis was verified by comparing it with simulated and measured results.

Active 3-D microscaffold system with fluid perfusion for culturing in vitro neuronal networks.

This work demonstrated the design, fabrication, packaging, and characterization of an active microscaffold system with fluid perfusion/nutrient delivery functionalities for culturing in vitro neuronal networks from dissociated hippocampal rat pup neurons. The active microscaffold consisted of an 8 x 8 array of hollow, microfabricated, SU-8 towers (1.0 mm or 1.

Spatiotemporal localization of injury potentials in DRG neurons during vincristine-induced axonal degeneration.

The distal to proximal degeneration of axons, or "dying back" is a common pattern of neuropathology in many diseases of the PNS and CNS. A long-standing debate has centered on whether this pattern of neurodegeneration is due to an insult to the cell body or to the axon itself, although it is likely that mechanisms are different for specific disease entities. We have addressed this question in a model system of vincristine-induced axonal degeneration.

A multielectrode microcompartment culture platform for studying signal transduction in the nervous system.

This paper describes the design, fabrication, and characterization of a microfabricated compartmented culture system (micro-CCS) useful for electrophysiological signaling studies in cultured neurons. The focus of the paper is the process of interfacing the micro-CCS with cultured neurons and to demonstrate the applicability of the system for biochemical-mediated electrophysiological studies. Moreover, we show that we can record action potentials from cultured neurons through the extracellular compartmented application of elevated levels of K(+) ions.

Quantification of the heterogeneity in breast cancer cell lines using whole-cell impedance spectroscopy.

Purpose: Quantification of the heterogeneity of tumor cell populations is of interest for many diagnostic and therapeutic applications, including determining the cancerous stage of tumors. We attempted to differentiate human breast cancer cell lines from different pathologic stages and compare that with a normal human breast tissue cell line by characterizing the impedance properties of each cell line.

Experimental Design: A microelectrical impedance spectroscopy system has been developed that can trap a single cell into an analysis cavity and measure the electrical impedance of the captured cell over a frequency range from 100 Hz to 3.

Three dimensional MEMS microfluidic perfusion system for thick brain slice cultures.

In vitro tissue culture models are often benchmarked by their ability to replicate in vivo function. One of the limitations of in vitro systems is the difficulty in preserving an orchestrated cell population, especially for generating three-dimensional tissue equivalents. For example, tissue-engineering applications involve large high-density constructs, requiring a perfusing system that is able to apply adequate oxygen and nutrients to the interior region of the tissue.

Ion channel characterization using single cell impedance spectroscopy.

A micro electrical impedance spectroscopy system (microEIS) for single cell analysis has been developed and used to differentiate ion channel activities of bovine chromaffin cells. K+ and Ca2+ channels were blocked and their electrical impedances were measured over a frequency range of 100 Hz to 5.0 MHz and compared to that of unblocked chromaffin cells.

A compartmented neuronal culture system in microdevice format.

This paper describes a microfabricated compartmented culture system (mu-CCS) for studying the effects of drugs on cultured neurons. We describe the fabrication of the microsystem and show the ability to culture DRG neurons in the microsystem. Furthermore, we demonstrate the ability to culture neurons with extensions growing into adjoining compartments while maintaining fluid isolation between compartments.

Microsystems for isolation and electrophysiological analysis of breast cancer cells from blood.

This paper presents the development of a microsystem for separating suspended breast cancer cells in peripheral blood and for sorting them based on their electrophysiological characteristics. A continuous paramagnetic capture mode (PMC) magnetophoretic microseparator was utilized for the isolation of suspended breast cancer cells in peripheral blood based on the native magnetic properties of blood cells without any tagging such as with magnetic probes. A micro-electrical impedance spectroscopy (mu-EIS) system was used as a downstream cell analysis tool to extract the pathological characteristics from the breast cancer cells.

Point-of-care biosensor systems for cancer diagnostics/prognostics.

With the growing number of fatalities resulting from the 100 or so cancer-related diseases, new enabling tools are required to provide extensive molecular profiles of patients to guide the clinician in making viable diagnosis and prognosis. Unfortunately with cancer-related diseases, there is not one molecular marker that can provide sufficient information to assist the clinician in making effective prognoses or even diagnoses. Indeed, large panels of markers must typically be evaluated that cut across several different classes (mutations in certain gene fragments--DNA; over/under-expression of gene activity as monitored by messenger RNAs; the amount of proteins present in serum or circulating tumor cells).

Paramagnetic capture mode magnetophoretic microseparator for high efficiency blood cell separations.

This paper presents the characterization of continuous single-stage and three-stage cascade paramagnetic capture (PMC) mode magnetophoretic microseparators for high efficiency separation of red and white blood cells from diluted whole blood based on their native magnetic properties. The separation mechanism for both PMC microseparators is based on a high gradient magnetic separation (HGMS) method. This approach enables separation of blood cells without the use of additives such as magnetic beads.

Multi-layer plastic/glass microfluidic systems containing electrical and mechanical functionality.

This paper describes an approach for fabricating multi-layer microfluidic systems from a combination of glass and plastic materials. Methods and characterization results for the microfabrication technologies underlying the process flow are presented. The approach is used to fabricate and characterize multi-layer plastic/glass microfluidic systems containing electrical and mechanical functionality.

Geometric scaling effects in electrical field flow fractionation. 2. Experimental results.

Geometric scaling of microelectrical field flow fractionation (micro-EFFF) systems is investigated experimentally and compared to theory and to macroscale EFFF systems. Experimental results are presented to demonstrate that the miniaturized system operates according to the scaling theory associated with the system. Demonstrated improvements in the channels include increased retention and resolution and decreased peak broadening, electrical time constants, relaxation time, power consumption, and sample size.

A microfabricated thermal field-flow fractionation system.

A microscale thermal field-flow fractionation (micro-TFFF) system has been designed, fabricated, and characterized. Motivation for miniaturization of TFFF systems was established by examining the geometrical scaling of the fundamental TFFF theory. Miniaturization of conventional macroscale TFFF systems was made possible through utilization of micromachining technologies.