Publications

Nanomaterial Synthesis and Integration for Sensor and Energy Applications

Heather Chiamori
Liwei Lin
Samuel S. Mao
John Clarke
Oscar D. Dubo ́n
2012

Nanostructures have unique properties that will be leveraged for next generation sensor and energy applications: large surface-to-volume ratios, increased sensitivity at lower input power levels, and higher current densities all contribute to increased functionality of nano- structure devices. The synthesis and integration of carbon-, metal-, and metal oxide-based nanostructures for sensor and energy applications are studied with the goal of nano-to-micro devices utilizing well-established micro- and nano-fabrication tools and techniques: (1) self- assembled, integrated carbon...

Microengineered Platforms For Assessing Cell-Cell Communication and Single-Cell Influences on Adult Neural Stem Cell Fate

Sisi (Siyu) Chen
Michel M. Maharbiz
David V. Schaffer
Henk Roelink
Zev Gartner
2012

The signaling environment experienced by a single cell is highly dependent on its interactions with its neighbors, which may secrete locally acting factors or act via membrane bound receptor-ligand systems. Stem cells are particularly sensitive to these signals, which act in concert to regulate self-renewal and discrete transitions into distinct fates. In the case of the adult neural stem cell, decades of in vivo and in vitro work have illustrated specific roles for different types of niche cells and some of the molecular mediators...

Electrospun Direct-write Multi-functional Nanofibers

Jiyoung Chang
Liwei Lin
Albert P. Pisano
2012

Multi-functional fibers by means of direct-write near-field electrospinning process have been developed for versatile applications on a wide variety of substrates, including flexible ones. Several mask-less lithographoy techniques have been established by using the direct- write fibers in dry etching, wet etching and lift-off processes. By selecting the proper functional materials, electrospun direct-write fibers have been demonstrated in prototype working devices, such as large array piezoelectric nanogenerators made of polymeric PVDF (Polyvinylidene fluoride) and direct-write micro...

Polymer Microfluidic Device for High-throughput Single-cell Encapsulation, Lysis, and Biological Assay

Timothy Brackbill
Albert P. Pisano
Liwei Lin
Amy Herr
2012

Single cell analysis is the present and future of biological research. It’s becoming clear that sub-populations of cells within a larger group can often be the culprit for diseases or malfunctions. In this work we aim to provide a tool that allows biological researchers to better analyze single cells within cell populations by removing the barrier to observing analytes contained within the cell’s membrane. By providing physical access to the intracellular compounds in a single cell, we can analyze individual cells for levels of analytes that were previously only available through...

MEMS Materials and Temperature Sensors for Down Hole Geothermal System Monitoring

Sarah Wodin-Schwartz
Albert P. Pisano
Liwei Lin
2013

The advancement of renewable energy technologies is critical due to the unsustainable nature of currently used energy sources and the need to meet increasing energy demands. A broad and diverse energy plan is important for long term energy independence and stability. Geothermal energy sources including hydrothermal systems and enhanced geothermal systems (EGS) should play a key role in this energy plan. Geothermal energy is the most reliable, currently developed, schedulable alternative energy source. It is estimated that improvements in these systems have the potential to...

Nanomaterials Processing Toward Large-scale Flexible/Stretchable Electronics

Toshitake Takahashi
Ali Javey
Tsu-Jae King Liu
Liwei Lin
2013

In recent years, there has been tremendous progress in large-scale mechanically flexible electronics, where electrical components are fabricated on non-crystalline substrates such as plastics and glass. These devices are currently serving as the basis for various applications such as flat-panel displays, smart cards, and wearable electronics.

In this thesis, a promising approach using chemically synthesized nanomaterials is explored to overcome various obstacles current technology faces in this field. Here, we use chemically synthesized semiconducting nanowires (...

Microfluidic Modules for Enabling Point-of-Care Biopsy-based Cancer Diagnostics

Debkishore Mitra
Luke P. Lee
Shuvo Roy
Lee W. Riley
2013

The analyses of patient tumor biopsy samples and biopsy-based diagnostics have emerged as important tools for cancer diagnostics. However, the techniques employed currently are restricted to centralized laboratories as they are time-consuming, manual labor intensive and vary considerably in their effectiveness amongst institutions and countries. Point of Care testing (POCT) for cancer with the capacity for multiplexed detection of numerous biomarkers in biopsy samples in a rapid, precise and portable manner is emerging as an area with enormous potential to disseminate universal...

Copper Oxide by Thermal Oxidation for Electrochemical Cells and Gas Sensors

Kevin Limkrailassiri
Liwei Lin
Costas Grigoropoulos
Roya Maboudian
2013

Advances in electrolytic and gas sensing technologies continue to be driven by careful selection and engineering of materials. Copper oxides—both cuprous oxide, Cu2O, and cupric oxide, CuO—are abundant, environmentally friendly, and highly versatile. An attractive feature unique to both copper oxides is the ease of synthesis through a one-step thermal oxidation of copper foil in ambient environment, yielding various oxide compositions and morphologies according to the oxidation temperature and time. There are many possible applications for the copper oxide...

Harsh Environment Silicon Carbide UV Sensor and Junction Field-Effect Transistor

Wei-Cheng Lien
Albert P. Pisano
Tsu-Jae King Liu
Elad Alon
2013

A harsh environment can be defined by one or more of the following: High temperature, high shock, high radiation, erosive flow, and corrosive media. Among all the harsh environment applications, high temperature applications have drawn lots of attention due to the emerging activity in automotive, turbine engine, space exploration and deep-well drilling telemetry. Silicon carbide has become the candidate for these harsh environment applications because of its wide bandgap, excellent chemical and thermal stability, and high breakdown electric field strength. This dissertation details...

High-Resolution μECoG: Design, Fabrication, and Applications

Peter Ledochowitsch
Michel M. Maharbiz
Jose M. Carmena
Robert T. Knight
Christoph E. Schreiner
2013

Since the early 1950s, electrocorticography (ECoG), the measurement of electrical po- tentials on the surface of the brain has become an invaluable tool in neurosurgery for the localization of epileptic foci before resection. The ECoG electrodes used in clinical practice are made in an archaic serial process that involves hand-soldering wires to a stiff, coarse grid of electrodes with a spatial resolution >1 cm, and a tangle of transcranial wires. In this thesis we report a modern microfabrication process based on photolithographic pat- terning of...