Chen, Qiulan. / "November 2010." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 140-152). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

The purpose of the thesis is to design and develop a network of automated, distributed, living cell-based sensors, called CytoSensors. Their main role is to detect a variety of biological and chemical toxins. The system is designed to help researchers to carry out multitude of experiments, in order to build a practical knowledge base in toxin detection. The network is developed in accordance with industry standards, to be used and deployed for prevention in inhospitable environments such as battlefields, toxic urban locations or polluted agricultural regions. The sensor is composed of a processing unit (processor and memory), an archiving unit (permanent data storage), a communication unit, input devices attached to a data acquisition unit, and control devices. The CytoSensor is specifically designed to acquire and analyze visual information about the living cells: hence cameras are used as input devices and frame grabbers are used as the digitizers. The control devices are additional external devices developed to help control and automate the process of data acquisition: they comprise light intensity control USB boards to provide the correct amount of light to view the cells, touch panels for user-instrument interaction, and bar code readers to identify vials and experiments. The software, on the other hand, is a complex mosaic of different elements, each of which has a specific task to accomplish. These building blocks include the real-time acquisition, archiving, networking, processing, modelling, sensor output presentation and user interfaces. Our goal is to develop, integrate and optimize all these components to produce a viable and working device. The prototypes evolved from an offline, portable sensor equipped with a single high-resolution CCD camera and high-quality optics, to distributed online sensors with multiplexed CCD cameras and affordable optics. The acquisition board digitizes in real time the images from one to twelve multiplexed high resolution cameras. Several operational requirements must be met. First, a fault-tolerant and stable control over the input devices and control devices must be provided. Secondly, acquisition timing errors should be minimized as a trade-off between performance and the use of a low-cost, general-purpose, industry-standard operating system such as Microsoft Windows NT. Finally, in order to reduce development time and increase code reusability, a common abstraction layer is designed to provide for flexible use with various types of digitizers and cameras. As part of a distributed detection network, each sensor is able to exchange data with other "trusted" sensors and users, and to allow remote control of certain tasks. The sensor may be seen as a node capable of transmitting and receiving acquired or processed data to a distant device (another sensor, a workstation or a PDA) for visualization, inspection and decision-making by a front-end user. Each node on the network provides a set of complementary services including data acquisition, data processing, communication and system. The mandatory system service monitors the local system performance and manages data archiving. The communication service connects the various services on the network by enabling message-passing, file transfer and caching. The sensor network integrates a lightweight, interoperable and flexible RPC (Remote Procedure Call) protocol to achieve real-time control and monitoring of these distributed resources. A reliable embedded database system is used to store metadata bound to acquired and processed images. This database is also used to maintain information on neighbor nodes, and to check access credentials of available local services. Finally, by adding store-and-forward messaging capabilities, the application can be extended to work in wireless and mobile networks. / Graduation date: 2003

Ho, Yee Man Martina = 硒化鎘三維納米結構之製作及其感應脫氧核糖核酸之應用潛能 / 何綺雯. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references. / Abstract also in Chinese. / Ho, Yee Man Martina = Xi hua ge san wei na mi jie gou zhi zhi zuo ji qi gan ying tuo yang he tang he suan zhi ying yong qian neng / He Qiwen. / Chapter Chapter 1 --- Introduction / Chapter 1 --- Photovoltaic properties of CdSe --- p.1 / Chapter 1.1 --- Quantum size effect --- p.1 / Chapter 1.2 --- Synthesis of CdSe nanostructures --- p.3 / Chapter 1.3 --- Electrochemical sensing of CdSe nanostructures --- p.4 / Chapter 1.3.1 --- Surface passivation and functionalization of CdSe nanostructures --- p.5 / Chapter 1.4 --- Electronic properties of nanocrystalline semiconductor electrode --- p.6 / Chapter 1.4.1 --- Band alignment --- p.6 / Chapter 1.4.2 --- Interfacial charge transfer process --- p.9 / Chapter 1.4.3 --- Surface traps and adsorbed molecules --- p.10 / Chapter 1.4.4 --- DNA molecules as a capping group --- p.11 / Chapter 1.5 --- Literatures review in DNA sensing --- p.12 / Chapter 1.6 --- Present study --- p.14 / Chapter 1.6.1 --- Objective --- p.14 / Chapter 1.6.2 --- General methodology --- p.15 / Chapter Chapter 2 --- Experimental / Chapter 2.1 --- Introduction into the instrumentation of this project --- p.21 / Chapter 2.2 --- CHI Electrochemical workstation --- p.22 / Chapter 2.2.1 --- Linear sweep voltammetry --- p.24 / Chapter 2.2.2 --- Cyclic voltammetry --- p.24 / Chapter 2.2.3 --- Multiple potential step --- p.25 / Chapter 2.3 --- CEM Microwave-assisted chemical synthesizer --- p.27 / Chapter 3.1 --- Morphological examination by scanning electron microscopy --- p.28 / Chapter 3.2 --- Elemental analysis by energy dispersive x-ray spectroscopy --- p.30 / Chapter 3.3 --- Crystal structure analysis by x-ray diffraction --- p.31 / Chapter 3.4 --- Surface compositional analysis by x-ray photoelectron spectroscopy --- p.32 / Chapter 3.5 --- Transmission electron microscopy --- p.34 / Chapter Chapter 3 --- Synthesis of 3D nanostructured CdSe multipod electrodes / Chapter 3.1 --- Introduction into the synthesis of CdSe MP electrode --- p.35 / Chapter 3.2 --- Recipe for the synthesis of CdSe NPs --- p.36 / Chapter 3.3 --- The synthesis of CdSe MPs --- p.37 / Chapter 3.3.1 --- Tuning the experimental parameters: Reaction temperature --- p.37 / Chapter 3.3.2 --- Tuning the experimental parameters: Reaction hold time --- p.46 / Chapter 3.3.3 --- Tuning in experimental parameters: Precursor molar ratio --- p.50 / Chapter 3.4 --- The fabrication of MP CdSe on a conductive substrate --- p.54 / Chapter 3.4.1 --- The electrodeposition of CdSe thin films on ITO/glass substrates --- p.55 / Chapter 3.4.2 --- The growth of CdSe MPs on CdSe/ ITO/glass --- p.57 / Chapter 3.5 --- The characterization of MP CdSe electrode --- p.57 / Chapter Chapter 4 --- Electrical and opto-electric characteristics of CdSe MP electrodes and their applications as platforms for the DNA recognition / Chapter 4.1 --- Introduction to the property characterization of CdSe MP electrodes --- p.62 / Chapter 4.2 --- DNA surface attachment --- p.64 / Chapter 4.2.1 --- Mechanism of DNA surface anchoring --- p.65 / Chapter 4.3 --- I-V characterization in PBS --- p.69 / Chapter 4.3.1 --- Experimental procedures of the I-V tests in PBS --- p.70 / Chapter 4.3.2 --- Results and discussions of I-V tests in PBS --- p.72 / Chapter 4.3.2.1 --- Exercising as-prepared CdSe MP electrode --- p.74 / Chapter 4.3.2.2 --- I-V characteristics of CdSe MP electrodes before and after ssDNA attachment --- p.75 / Chapter 4.3.2.3 --- I-V characteristics of CdSe MP electrodes before and after the dsDNA attachment --- p.76 / Chapter 4.3.2.4 --- "Photo-response of bare CdSe MP, ssDNA/CdSe MP and dsDNA/CdSe electrodes" --- p.77 / Chapter 4.4 --- "Photovoltaic I-V measurement in I3""/I"" redox electrolyte" --- p.79 / Chapter 4.4.1 --- Experimental procedures --- p.79 / Chapter 4.4.2 --- Results and discussions --- p.80 / Chapter 4.5 --- Possible application implied by the results --- p.88 / Chapter 4.5.1 --- DNA base pair mismatch identification --- p.91 / Chapter 4.5.2 --- Field-assisted DNA hybridization acceleration process --- p.92 / Chapter Chapter 5 --- Conclusions / Chapter 5.1 --- Conclusions --- p.95

This thesis presents a novel algorithmic A/D converter to be used in a biosensor. The converter is capable of a conversion rate of 1.5 bits/phase and hence the required conversion time is reduced. The proposed architecture is analyzed for non-ideal effects and compared with existing algorithmic A/D architectures. The converter needs only one op-amp, 4 comparators and 3 capacitors. Power reduction techniques are discussed with respect to the biosensor and the ADC. The ADC is designed for fabrication in a CMOS 0.18μm process. / Graduation date: 2004

Electron-excited surface plasmon resonance (eSPR) is investigated for potential use in biosensors. Optical SPR sensors are commercially available at present and these sensors are extremely sensitive, but have the tendency to be relatively large, expensive, and ignore the potentials of microelectronic technology. By employing the use of various microelectronic and nanotechnology principles, the goal is to eventually design a device that exploits the eSPR phenomenon in order to make a sensor which is siginificantly smaller in size, more robust, and cheaper in cost.

The objective of this thesis is to introduce and demonstrate a novel magnetic bead detector based on inductive detection at the ferromagnetic resonance (FMR) frequency for use in bio-sensing applications. Detection ability is demonstrated through theoretical arguments, numerical computer simulations, and experimental characterization of micro-fabricated detectors. The detector is composed of two uniplanar rf waveguides (coplanar waveguide and slotline) terminated together at a short-circuit junction, which serves as the sensitive area. Experimental characterization of a micro-fabricated junction gives a signal ranging between 1 microvolt/volt and 12 microvolts/volt, depending on the number of beads at the junction as well spatial distribution of the beads. The locations around the tips of the CPW were shown to be the most sensitive. A more complex rf circuit design was created employing the detection junction, and detection of magnetic beads was successfully shown at rf frequencies around 6 GHz in this configuration. Due to lack of FMR characterization data for magnetic beads in the literature, several varieties of magnetic beads were characterized using a CPW transmission line and custom apparatus to determine FMR properties. Finally, successful detection of magnetic beads was demonstrated in a system-level integration experiment employing the detector junction in combination with microfluidics and bio-chemical surface modifications. / Graduation date: 2010

No description available.

This paper introduces an alternative technique for the development of microfluidic systems for biotechnology based on mechanical machining and ultrasonic welding. Advantages of this approach over existing prototyping approaches involving the rapid development of tooling include: (a) short cycle time, (b) design flexibility, and (c) low cost manufacturing. In addition, the process provides a migration path to high volume production. A limitation of this system is that it cannot practically produce microchannels smaller than about 250 μm (0.010 in). However, for many biological cell-based biosensors, this feature scale seems well suited based on cell viability results. Several issues are discussed relevant to this approach, including bond strength, seal leakage, and sterilization. / Graduation date: 2002

The Microelectronics Group has been researching sensors useful for detecting and quantifying events in biological molecular chemistry, for example, binding events. Our previous research has been based primarily on quartz resonators. This thesis describes the results of our initial research of Surface Plasmon Resonance (SPR) based technology. This study contains the design and implementation of a fully functional SPR biosensor with detailed disclosure of monolayer construction, digital hardware interfaces and software algorithms for process the SPR sensors output. An antibody monolayer was constructed on the biosensor surface with the goal of setting the strengths, weaknesses and limitation of measuring molecular events with SPR technology. We documented several characteristics of molecular chemistry that directly effect any measurements made using Surface Plasmon Resonance technology including pH, free ions, viscosity and temperature. Furthermore, the component used in our study introduced additional limitations due to wide variations amongst parts, the constraint of a liquid medium and the large surface area used for molecular interrogation. We have identified viable applications for this sensor by either eliminating or compensating for the factors that affect the measured results. This research has been published at the inaugural IEEE sensors conference and to our knowledge is the first time a biosensor has been constructed by attaching a sensor to a PDA and performing all signal processing, waveform analysis and display in the PDAs core processor.

The contamination of drinking water by microbial pathogens is recognized as one of the most pressing water supply problems of our day. To minimize the impact of pathogens and parasites on the environment and public health, accurate methods are needed to evaluate their presence and concentration. Although various techniques exist to detect certain pathogens in water (e.g., immunofluorescence or PCR techniques), these are time- and labor-intensive. A direct, real-time method for detection and quantification of target organisms would thus be very useful for rapid diagnosis of water safety. A quartz crystal microbalance with dissipation monitoring (QCM-D) based biosensor for detection of waterborne pathogens (i.e., Escherichia coli O157:H7) was developed. The detection platform is based on the immobilization of affinity purified antibodies onto gold coated QCM-D quartz crystals via a cysteamine self-assembled monolayer. The results show that the optimal sensor response is the initial slope of the dissipation shift. A highly log-log linear response is obtained for detection of E. coli O157:H7 over a broad range of cell concentration from 3 x 105 to 1 x 109 cells/mL. The prepared biosensor also exhibits a log-log linear working range from 107 to 109 cells/mL for E. coli K12 D21, a non-pathogenic model organism. The biosensor also shows satisfactory selectivity using Bacillus subtilis . To our knowledge, this is the first study demonstrating the use of the slope of the dissipation shift as a sensor response when using QCM-D technology. / Keywords: Biosensor, QCM-D, E. coli O157:H7, polyc1onal antibodies, dissipation slope, cysteamine, self-assembled monolayer