Cloning by nuclear transfer using mammalian somatic cells has enormous potential application. However, cloning mammalian species through somatic cell nuclear transfer has been simply inefficient in all species in which live clones have been produced, such as ‘Dolly’ the sheep, and ‘Samrupa’ the buffalo. Most of the experiments resulted failure, and the success rate ranges from 0.1% to 3%. Developmental defects have been attributed to incomplete reprogramming of the somatic nuclei by the cloning process. Researchers have tried strategies to improve the efficiency of nuclear transfer. However, significant breakthroughs are yet to happen. The enucleation procedure consisting of extracting reprogrammable genetic material during nuclear transfer has been linked to inefficiencies due to manual error, lack of repeatability and decreased high throughput. Conventional manual enucleation process requires a series of complicated cell rotation in three-dimensional (3D) spaces using a blunt or sharp tipped pipette, and can puncture the cell during genetic material extraction. Current methods frequently damage the cell via physical or chemical contact, and thus have low throughput. Therefore, there is a need for simple, readily automated, non-contact methods for controlled cell rotation. Precise rotation of the suspended cells is one of the many fundamental manipulations in a wide range of biotechnological applications, such as cell injection and enucleation. Noticeably scarce from the existing rotation techniques is 3D rotation of cells on one single chip. To bridge this gap, this research presents a means of controlled cell rotation for bovine oocytes around both the in-plane (yaw) and out-of-plane (pitch) axes using a simple, low cost biochip fabricated using a mixture of conventional lithography and low-cost micro-milling. It uses a phase varying dielectrophoresis (DEP)-based electrorotation (EROT) biochip platform, which has an open-top sub-millimetre square chamber enclosed by four sidewall electrodes and two bottom electrodes to induce torque to rotate the cells about two axes, thus 3D cell rotation for the first time. Before fabrication, phase varying DEP-based rotational electric field simulations were carried out in the designed rotation chamber. For this analysis, initial rotational fields are characterised for both in-plane and out-of-plane axes using multi-physics finite element software. Electrode shape and chamber design were optimised using realistic parameters for the medium and electrode material properties. Results showed remarkable promise to rotate dielectric particles in rotational field strengths of the order of 104 V/m. From simulations, a basic biochip design was optimised. Within the fabricated biochip, controlled rotations around the in-plane and out-of-plane axes were demonstrated, and the electric field activation frequency range and electrokinetic properties of the bovine oocytes were characterised. Rotation was measured via video image processing with data included on electronic annex. Results show controllable rotation in steps of 5 degrees around both axes with the same chip. In experiments, the maximum rotation rate reached 150°/s in yaw axis and 45-50°/s during pitch axis, while a smooth, stable and controllable rotation rate was found below 30-40°/s. Optimum rotation rates are found for inputs of 10 Vp-p at 500-800 kHz AC frequency for yaw-axis rotation, and 10-20 Vp-p and 10-100 kHz for pitch-axis rotation. In addition, zona intact and zona free oocytes are shown to have electrical equivalence and found no noticeable difference, generalising the bio-chips capability and results. Further, experimental results were used to validate the numerical solid shell model used in design and it was found that the bovine oocytes are highly polarizable than the surrounding medium. Finally, the dielectric properties of the oocytes were fully characterised enabling further design optimization in future, if desired. The biochip was successfully designed, optimised and experimentally validated, and successful rotation of bovine oocytes in 3D spaces was demonstrated. These results create a platform tool for biologists to utilise enucleation with high throughput efficiency and ease. In summary, this simple, transparent, low-cost, open-top, and biocompatible biochip platform, allows further function modules to be integrated and is the foundation for more powerful cell manipulation systems. In brief key novel aspects of the research were: • Rotation of suspended spherical oocytes in multiple axes (3D rotation) was obtained by AC induced electric fields. • An open top biochip was successfully fabricated to enable further processing of the rotated cell in 3D spaces. • Bovine oocyte dielectric spectra were analysed in both in-plane and out-of-plane axes for the first time. • Bovine oocytes were determined to behave as solid spherical spheres, rather than single spherical shells.

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The introduction of microassembly technologies has opened up new venues for the fabrication of sophisticated, three-dimensional Microelectromechanical System (MEMS) devices. This thesis presents the development of a robotic micromanipulation system and its controller algorithms for conventional pick-and-place microassembly processes. This work incorporated the approach of parallel assembly and automation to improve overall productivity and reduce operating costs of the process. A parallel set of three microgrippers was designed and implemented for the grasping and assembly of three microparts simultaneously. The complete microassembly process was automated through a vision-based control approach. Visual images from two vision systems were adopted for precise position evaluation and alignment. Precise alignment between the micropart and microgripper is critical to the microassembly process. Due to the limited field of view of the vision systems, the micropart could displace away from the microscope field of view during the re-orientation process. In this work, a tracking algorithm was developed to constrain the micropart within the camera view. The unwanted translational motions of the micropart were estimated. The algorithm then continuously manipulated and repositioned the micropart for the vision-based assembly. In addition, the limited fields of view of the vision systems are not sufficient to concurrently monitor the assembly operation for all three individual grippers. This work presents a strategy to use visual information from only one gripper set for all the necessary alignment and positioning processes. Through proper system calibration and the alignment algorithms developed, grippers that were not visually monitored could also perform the assembly operations. When using visual images from a single vision camera for 3D positioning, the extra dimension between the 2D image and 3D workspace results in errors in position evaluation. Hence, a novel approach is presented to utilize image reflection of the micropart for online evaluation of the Jacobian matrix. The relative 3D position between the slot and micropart was evaluated with high precision. The developed algorithms were integrated onto the micromanipulation system. Automated parallel microassemblies were conducted successfully.

This thesis presents the theoretical analysis and experiment results of MEMS sensors designed for the application of low frequency vibration sensing. Each sensor consists of a proof mass connected to a folded beam micro-flexure, with an attached capacitive comb drive for displacement sensing. Three comb drive arrangements are evaluated, the transverse, lateral, and tri-plate differential. The sensors are fabricated using the well developed foundry processes of PolyMUMPS and SoiMUMPS. In addition, a capacitance to voltage readout circuit is fabricated using discrete components. Static tests, evaluating the capacitance to displacement relation, are conducted on a six degree of freedom robotic manipulator, and dynamic tests evaluating the sensor response to sinusoidal excitations are conducted on a vibrating beam. The end use of the sensor involves real-time vibration monitoring of automobile mechanical systems, such as power seats, windshield wipers, mirrors, trunks, and windows, allowing for early detection of mechanical faults before catastrophic failure.

This thesis deals with the fabrication of MEMS air quality sensors for automotive applications. The goal of this project is to design, fabricate and test an integrated sensor that measures three important air quality components inside the automotive cabin, which are temperature, relative humidity and carbon monoxide (CO) concentration. The sensors are fabricated on silicon substrate covered with thermal oxide and LPCVD nitride. Various deposition and etching techniques were utilized to fabricate these sensors including E-beam evaporation, thermal oxide growth, PECVD, LPCVD, RIE, KOH and HF etching. The temperature and humidity sensor use nickel as the sensitive material while the CO sensor was designed to use SnO2 although it was not fabricated to completion. A chamber was created where the temperature and humidity are controlled and the sensors were tested. Curves of sensor resistance vs. temperature and sensor resistance vs. humidity were created and the two sensor’s sensitivity was calculated.

The introduction of microassembly technologies has opened up new venues for the fabrication of sophisticated, three-dimensional Microelectromechanical System (MEMS) devices. This thesis presents the development of a robotic micromanipulation system and its controller algorithms for conventional pick-and-place microassembly processes. This work incorporated the approach of parallel assembly and automation to improve overall productivity and reduce operating costs of the process. A parallel set of three microgrippers was designed and implemented for the grasping and assembly of three microparts simultaneously. The complete microassembly process was automated through a vision-based control approach. Visual images from two vision systems were adopted for precise position evaluation and alignment. Precise alignment between the micropart and microgripper is critical to the microassembly process. Due to the limited field of view of the vision systems, the micropart could displace away from the microscope field of view during the re-orientation process. In this work, a tracking algorithm was developed to constrain the micropart within the camera view. The unwanted translational motions of the micropart were estimated. The algorithm then continuously manipulated and repositioned the micropart for the vision-based assembly. In addition, the limited fields of view of the vision systems are not sufficient to concurrently monitor the assembly operation for all three individual grippers. This work presents a strategy to use visual information from only one gripper set for all the necessary alignment and positioning processes. Through proper system calibration and the alignment algorithms developed, grippers that were not visually monitored could also perform the assembly operations. When using visual images from a single vision camera for 3D positioning, the extra dimension between the 2D image and 3D workspace results in errors in position evaluation. Hence, a novel approach is presented to utilize image reflection of the micropart for online evaluation of the Jacobian matrix. The relative 3D position between the slot and micropart was evaluated with high precision. The developed algorithms were integrated onto the micromanipulation system. Automated parallel microassemblies were conducted successfully.

This thesis presents the theoretical analysis and experiment results of MEMS sensors designed for the application of low frequency vibration sensing. Each sensor consists of a proof mass connected to a folded beam micro-flexure, with an attached capacitive comb drive for displacement sensing. Three comb drive arrangements are evaluated, the transverse, lateral, and tri-plate differential. The sensors are fabricated using the well developed foundry processes of PolyMUMPS and SoiMUMPS. In addition, a capacitance to voltage readout circuit is fabricated using discrete components. Static tests, evaluating the capacitance to displacement relation, are conducted on a six degree of freedom robotic manipulator, and dynamic tests evaluating the sensor response to sinusoidal excitations are conducted on a vibrating beam. The end use of the sensor involves real-time vibration monitoring of automobile mechanical systems, such as power seats, windshield wipers, mirrors, trunks, and windows, allowing for early detection of mechanical faults before catastrophic failure.

This thesis deals with the fabrication of MEMS air quality sensors for automotive applications. The goal of this project is to design, fabricate and test an integrated sensor that measures three important air quality components inside the automotive cabin, which are temperature, relative humidity and carbon monoxide (CO) concentration. The sensors are fabricated on silicon substrate covered with thermal oxide and LPCVD nitride. Various deposition and etching techniques were utilized to fabricate these sensors including E-beam evaporation, thermal oxide growth, PECVD, LPCVD, RIE, KOH and HF etching. The temperature and humidity sensor use nickel as the sensitive material while the CO sensor was designed to use SnO2 although it was not fabricated to completion. A chamber was created where the temperature and humidity are controlled and the sensors were tested. Curves of sensor resistance vs. temperature and sensor resistance vs. humidity were created and the two sensor’s sensitivity was calculated.

The last few years have seen the start of a unique change in microphones for consumer devices such as smartphones or tablets. Almost all analogue capacitive microphones are being replaced by digital silicon microphones or MEMS microphones. MEMS microphones perform differently to conventional analogue microphones. Their greatest disadvantage is significantly increased self-noise or decreased SNR, while their most significant benefits are ease of design and manufacturing and improved sensitivity matching. This thesis presents research on speech processing, comparing conventional analogue microphones with the newly available digital MEMS microphones. Specifically, voice activity detection, speaker diarisation (who spoke when), speech separation and speech recognition are looked at in detail. In order to carry out this research different microphone arrays were built using digital MEMS microphones and corpora were recorded to test existing algorithms and devise new ones. Some corpora that were created for the purpose of this research will be released to the public in 2013. It was found that the most commonly used VAD algorithm in current state-of-theart diarisation systems is not the best-performing one, i.e. MLP-based voice activity detection consistently outperforms the more frequently used GMM-HMM-based VAD schemes. In addition, an algorithm was derived that can determine the number of active speakers in a meeting recording given audio data from a microphone array of known geometry, leading to improved diarisation results. Finally, speech separation experiments were carried out using different post-filtering algorithms, matching or exceeding current state-of-the art results. The performance of the algorithms and methods presented in this thesis was verified by comparing their output using speech recognition tools and simple MLLR adaptation and the results are presented as word error rates, an easily comprehensible scale. To summarise, using speech recognition and speech separation experiments, this thesis demonstrates that the significantly reduced SNR of the MEMS microphone can be compensated for with well established adaptation techniques such as MLLR. MEMS microphones do not affect voice activity detection and speaker diarisation performance.

The application of adaptive micro-electro-mechanical systems (MEMS) device in biologically-inspired cochlear model (cochlear biomodel) has been seen as a preferable approach to mimic closely the human cochlear response. The thesis focuses on the design and fabrication of resonant gate transistor (RGT) device applied towards the development of RGT cochlear biomodel. An array of RGT devices can mimic the cochlea by filtering the sound input signals into multiple electrical outputs. The RGT device consists of two main components; a) the MEMS bridge gate structure that transduces the sound input into mechanical vibrations and b) the channel with source/drain regions underneath the bridge gate structure that transduce the mechanical vibrations into electrical signals. The created mathematical model for RGT calculates the electrical outputs that are suited for neural spike coding. The neuromorphic auditory system is proposed by integrating the RGT devices with the spike event interface circuits. The novelty of the system lies in the adaptive characteristics of the RGT devices that can self-tune the frequency and sensitivity using the feedback control signals from the neuromorphic circuits. The bridge gates have been designed to cover the audible frequency range signals of 20 Hz - 20 kHz. Aluminium and tantalum have been studied as the material for the bridge gate structure. The fabrication of a bridge gate requires a gentle etch release technique to release the structure from a sacrificial layer. The downstream etch release technique employing oxygen/nitrogen plasma has been introduced and characterised. In the first iteration, aluminium bridge gates have been fabricated. The presence of tensile stress within aluminium had caused the aluminium bridge gates of length >1mm to collapse. In order to address this issue, tantalum bridge gates have been fabricated in the second iteration. Straight tantalum bridge gates in tensile stress and buckled tantalum bridge gates in compressive stress have been characterised. The frequency range of 550 Hz - 29.4 kHz has been achieved from the fabricated tantalum bridge gates of length 0.57mm - 5.8mm. The channel and source/drain regions have been fabricated and integrated with the aluminium or tantalum bridge gate structures to create the RGTs. In this study, the n-channel and p-channel resonant gate transistor (n-RGT and p-RGT) have been considered. In n-RGT, phosphorus ions are implanted to form the source/drain regions. High subthreshold currents have been measured from the n-RGTs. Thus, p- RGTs have been employed with considerably small subthreshold current. In p-RGT, boron ions are implanted to form the source/drain regions. The threshold voltage, transconductance and subthreshold current for both n-channel and p-channel resonant gate transistor devices have been characterised. In this work, the channel conductance of the n-RGT and p-RGT devices has been modulated successfully and the sensitivity tuning within the audible frequency range has been achieved from the tantalum bridge gates of the p-RGT devices. The characterisation and optimisation of the resonant gate transistor provide the first step towards the development of the adaptive RGT cochlear biomodel for the neuromorphic auditory system application.