CubeSat with Nanostructured Sensing Instrumentation for Planetary Exploration

This report provides a summary of the work performed under NIAC Phase I award NNX15AL86G entitled "CubeSat with Nanostructured Sensing Instrumentation for Planetary Exploration". The objective of this research is to investigate the feasibility of an innovative, low cost, CubeSat based planetary mission concept for in situ "ground truth"analysis of small asteroids and comets. The project includes an instrument study and a mission/spacecraft design study. The instrument study concerns with the development of anew TiO2 nanotube sensor with integrated compound semiconductor nanowires to determine surface composition element via neutron activated analysis (NAA). The mission/spacecraft design study concerns with the development of CubeSat based lander to small asteroids and comets. The Phase I study suggests that our concept is feasible and could provide significant benefit to NASA's future planetary missions. This research was carried out at the University of Southern California and the University of Utah

Growth and characterization of TiO2 nanotubes from sputtered Ti film on Si substrate

In this paper, we present the synthesis of self-organized TiO(2) nanotube arrays formed by anodization of thin Ti film deposited on Si wafers by direct current (D.C.) sputtering. Organic electrolyte was used to demonstrate the growth of stable nanotubes at room temperature with voltages varying from 10 to 60 V (D.C.). The tubes were about 1.4 times longer than the thickness of the sputtered Ti film, showing little undesired dissolution of the metal in the electrolyte during anodization. By varying the thickness of the deposited Ti film, the length of the nanotubes could be controlled precisely irrespective of longer anodization time and/or anodization voltage. Scanning electron microscopy, atomic force microscopy, diffuse-reflectance UV–vis spectroscopy, and X-ray diffraction were used to characterize the thin film nanotubes. The tubes exhibited good adhesion to the wafer and did not peel off after annealing in air at 350 °C to form anatase TiO(2). With TiO(2) nanotubes on planar/stable Si substrates, one can envision their integration with the current micro-fabrication technique large-scale fabrication of TiO(2) nanotube-based devices

Micro Electrical Impedance Spectroscopy of Bovine Chromaffin Cells

Single cell characterization using electrical impedance spectroscopy (EIS) has been conducted on bovine chromaffin cells. Measurements were taken using a micro scale electrophysiological analysis system fabricated using micromachining (e.g. MEMS) technologies. A population of chromaffin cells were injected into a microreservoir and subsequently manipulated into a microchannel with a cross-sectional area of 7.0×7.0 μm2. The microchannel was designed with integrated, opposing electroplated palladium electrodes with a cross-sectional area of 7.0×7.0 μm 2. The electrodes are designed to be in contact with the cells during analysis procedures. Impedance measurements were taken over a frequency range of 40 Hz to 3.0 MHz. Magnitude and phase were studied for a statistically relevant population of chromaffin cells. The impedance spectrums revealed three distinct populations of chromaffin cells. The data obtained for the chromaffin cells was compared to data obtained for red blood cells, air, and phosphate buffered solution

Detection of Four Distinct Volatile Indicators of Colorectal Cancer using Functionalized Titania Nanotubular Arrays

Screening of colorectal cancer is crucial for early stage diagnosis and treatment. Detection of volatile organic compounds (VOCs) of the metabolome present in exhaled breath is a promising approach to screen colorectal cancer (CRC). Various forms of volatile organic compounds (VOCs) that show the definitive signature for the different diseases including cancers are present in exhale breathe. Among all the reported CRC VOCs, cyclohexane, methylcyclohexane, 1,3-dimethyl- benzene and decanal are identified as the prominent ones that can be used as the signature for CRC screening. In the present investigation, detection of the four prominent VOCs related to CRC is explored using functionalized titania nanotubular arrays (TNAs)-based sensor. These signature biomarkers are shown to be detected using nickel-functionalized TNA as an electrochemical sensor. The sensing mechanism is based on the electrochemical interaction of nickel-functionalized nanotubes with signature biomarkers. A detailed mechanism of the sensor response is also presented

Micro Electrical Impedance Spectroscopy of Bovine Chromaffin Cells

Single cell characterization using electrical impedance spectroscopy (EIS) has been conducted on bovine chromaffin cells. Measurements were taken using a micro scale electrophysiological analysis system fabricated using micromachining (e.g. MEMS) technologies. A population of chromaffin cells were injected into a microreservoir and subsequently manipulated into a microchannel with a cross-sectional area of 7.0×7.0 μm2. The microchannel was designed with integrated, opposing electroplated palladium electrodes with a cross-sectional area of 7.0×7.0 μm 2. The electrodes are designed to be in contact with the cells during analysis procedures. Impedance measurements were taken over a frequency range of 40 Hz to 3.0 MHz. Magnitude and phase were studied for a statistically relevant population of chromaffin cells. The impedance spectrums revealed three distinct populations of chromaffin cells. The data obtained for the chromaffin cells was compared to data obtained for red blood cells, air, and phosphate buffered solution

A Micro System Using Dielectrophoresis and Electrical Impedance Spectroscopy for Cell Manipulation and Analysis

Single cell manipulation and analysis using dielectrophoresis (DEP) and micro electrical impedance spectroscopy (µ-EIS) has been demonstrated on bovine chromaffin cells and red blood cells. Cells were manipulated and analyzed on a micro scale electrophysiological analysis system fabricated using micromachining (e.g. MEMS) technologies. Cells were injected into a microreservoir and collected for µ-EIS analysis using vacuum and DEP. Impedance measurements were taken over a frequency range of 40 Hz to 3.0 MHz. The data obtained for the cells was compared to data obtained for air, and phosphate buffered solution. Data for chromaffin cells was analyzed further, assessing cell size and calcium ion channel activity in relation to impedance spectroscopy

A Micro System Using Dielectrophoresis and Electrical Impedance Spectroscopy for Cell Manipulation and Analysis

Single cell manipulation and analysis using dielectrophoresis (DEP) and micro electrical impedance spectroscopy (µ-EIS) has been demonstrated on bovine chromaffin cells and red blood cells. Cells were manipulated and analyzed on a micro scale electrophysiological analysis system fabricated using micromachining (e.g. MEMS) technologies. Cells were injected into a microreservoir and collected for µ-EIS analysis using vacuum and DEP. Impedance measurements were taken over a frequency range of 40 Hz to 3.0 MHz. The data obtained for the cells was compared to data obtained for air, and phosphate buffered solution. Data for chromaffin cells was analyzed further, assessing cell size and calcium ion channel activity in relation to impedance spectroscopy

Light-Assisted Anodized TiO₂ Nanotube Arrays

Self-assembled arrays of titania nanotubes are synthesized via electrochemical anodization of Ti foils under the presence of UV–vis irradiation. Compared to control samples (anodized without light), the light-assisted anodized samples exhibit larger diameters as well as thicker nanotube walls, whereas the length of the nanotubes remains the same under otherwise similar synthesis conditions. Enhanced photoelectrochemical performance with light-assisted anodized samples under simulated AM 1.5 irradiation is observed by an increase in photocurrent density of 45–73% at 1.23 V (RHE). The enhanced photoelectrochemical performance is correlated to improved charge separation analyzed by Mott–Schottky. A mechanism on the photoeffect during anodization is presented. The morphology and improved properties obtained from the synthesis methodology may also find application in other fields such as sensing and catalysi

Low-Cost Microfluidic Sensors with Smart Hydrogel Patterned Arrays Using Electronic Resistive Channel Sensing for Readout

There is a strong commercial need for inexpensive point-of-use sensors for monitoring disease biomarkers or environmental contaminants in drinking water. Point-of-use sensors that employ smart polymer hydrogels as recognition elements can be tailored to detect almost any target analyte, but often suffer from long response times. Hence, we describe here a fabrication process that can be used to manufacture low-cost point-of-use hydrogel-based microfluidics sensors with short response times. In this process, mask-templated UV photopolymerization is used to produce arrays of smart hydrogel pillars inside sub-millimeter channels located upon microfluidics devices. When these pillars contact aqueous solutions containing a target analyte, they swell or shrink, thereby changing the resistance of the microfluidic channel to ionic current flow when a small bias voltage is applied to the system. Hence resistance measurements can be used to transduce hydrogel swelling changes into electrical signals. The only instrumentation required is a simple portable potentiostat that can be operated using a smartphone or a laptop, thus making the system suitable for point of use. Rapid hydrogel response rate is achieved by fabricating arrays of smart hydrogels that have large surface area-to-volume ratios