A primary objective of modern biology is to understand the molecular mechanisms which underlie cellular functions and a crucial part of this task is the ability to manipulate and analyze individual cells. As a result of interdisciplinary research, microfluidics may become the forefront of analytical methods used by biologists. This technology can be used to gain unprecedented opportunities for cell handling, lysis and investigation on a single cell basis. This thesis presents the development of a microfluidic device capable of selecting individual cells and performing selective electrical lysis of the plasma membrane, while verifying intactness of the nuclear membrane. The device is fabricated by an improved photolithography method and integrates molten solder as electrodes for lysis by a DC electric field. Quantification of lysis is accomplished by video and image analysis, and measurement of the rate of ion diffusion from the cell.

An all-optical micromanipulation technique is presented in the framework of precise cell selection within a cell culture and multiplexed transport capabilities for microfluidic single cell analysis applications. The technique was developed by combining an optical tweezer setup with a novel integrated waveguide cell propulsion method referred to as end-face waveguide propulsion (EFWP). The EFWP technique delivers optical forces to a particle generating thrust. The thesis is divided into two sections: simulation and experimental validation. In the first section a new simulation technique based on ray optics theory (ROT) and the beam propagation method (BPM) is used to predict particle velocity and trajectory along a microfluidic propagation channel. In this work, the ROT-BPM technique is used to analyse and optimize the waveguide geometry to maximize particle velocity. Analysis of the impact of common microchip manufacturing limitations on velocity is performed to determine acceptable fabrication process tolerances. The second section presents experimental results of polymer microspheres and acute myeloid leukemia (AML) cells as biological targets. The experimental results are compared with simulations performed in the first section. Correction factors are added to the simulations to reflect the experimental device parameters. Thermal e_ects due to photon absorption within the fluidic channels are also investigated and corrected for. The final analysis indicates that the ROT-BPM technique developed in this work can be used to adequately predict particle velocity and trajectory path. EFWP currently delivers the fastest particle velocities compared to other optical micromanipulation techniques currently available in microfluidic applications. While the technique is focused on addressing chemical cytometry precise particle selectivity and high throughput needs, EFWP can also be used in many other single cell applications.

The recent breakthroughs in genomics and molecular diagnostics will not be reflected in health-care systems unless the biogenetic or other nucleic acid-based tests are transferred from the laboratory to clinical market. Developments in microfabrication techniques brought lab-on-a-chip (LOC) into being the best candidate for conducting sample preparation for such clinical devices, or point-of-care testing set-ups. Sample preparation procedure consists of several stages including cell transportation, separation, cell lysis and nucleic acid purification and detection. LOC, as a subset of Microelectromechanical systems (MEMS), refers to a tiny, compact, portable, automated and easy-to-use microchip capable of performing the sample-preparation stages together. Complexity in micro-fabrications and inconsistency of the stages oppose integration of them into one chip. Among the variety of mechanisms utilized in LOC for cell lysis, electrical methods have the highest potential to be integrated with other microchip-based mechanisms. There are, however, major limitations in electrical cell lysis methods: the difficulty and high-cost fabrication of microfluidic chips and the high voltage requirements for cell lysis. Addressing these limitations, the focus of this thesis is on realization of cell lysis microchips suitable for LOC applications. We have developed a new methodology of fabricating microfluidic chips with electrical functionality. Traditional lithography of microchannel with electrode, needed for making electro-microfluidic chips, is considerably complicated. We have combined several easy-to-implement techniques to realize electro-microchannel with laser-ablated polyimide. The current techniques for etching polyimide are by excimer lasers in bulky set-ups and with involvement of toxic gas. We present a method of ablating microfluidic channels in polyimide using a 30W CO2 laser. Although this technique has poorer resolution, this approach is more cost effective, safer and easier to handle. We have verified the performance of the fabricated electro-microfluidic chips on electroporation of mammalian cells. Electrical cell lysis mechanisms need an operational voltage that is relatively high compared to other cell manipulation techniques, especially for lysing bacteria. Microelectro-devices have dealt with this limitation mostly by reducing the inter-distance of electrodes. The technique has been realized in tiny flow-through microchips with built-in electrodes in a distance of a few micrometers which is in the scale of cell size. In addition to the low throughput of such devices, high probability of blocking cells in such tiny channels is a serious challenge. We have developed a cell lysis device featured with aligned carbon nanotube (CNT) to reduce the high voltage requirement and to improve the throughput. The vertically aligned CNT on an electrode inside a MEMS device provides highly strengthened electric field near the tip. The concept of strengthened electric field by means of CNT has been applied in field electron emission but not in cell lysis. The results show that the incorporation of CNT in lysing bacteria reduces the required operational voltage and improves throughput. This achievement is a significant progress toward integration of cell lysis in a low-voltage, high-throughput LOC. We further developed the proposed fabrication methodology of micro-electro-fluidic chips, described earlier, to perform electroporation of single mammalian cell. We have advanced the method of embedding CNT in microchannel so that on-chip fluorescent microscopy is also feasible. The results verify the enhancement of electroporation by incorporating CNT into electrical cell lysis. In addition, a novel methodology of making CNT-embedded microfluidic devices has been presented. The embedding methodology is an opening toward fabrication of a CNT-featured LOC for other applications.

Syftet med examensarbetet var att undersöka effekterna av ozonering och filtrering på råvattnet från sjön Mälaren. Studien är utförd i en pilotanläggning på Lovö vattenverk, Stockholm Vatten AB, under våren 2004. En negativ effekt med den konventionella reningen är den stora konsumtionen av kemiska koagulanter. Kemikalieanvändningen leder till många transporter och processen producerar också ett slam som för närvarande transporteras till Mälaren. År 2001 byggdes en pilotanläggning på Lovö vattenverk för utveckling av nya processer, en av processerna är ozonering följt av olika filter. Ozonering har använts i Europa i många år som desinfektion i slutet av dricksvattenreningsprocessen. Intresset för ozonering har ökat markant sista åren och idag används ozonet också i andra steg i processen. Förutom desinfektion har ozonet andra fördelar, som oxidation av järn och magnesium, mikroflockning, reduktion av lukt och smak samt är bra på att reducera färgen på vattnet. Mikroflockningen leder till att kemikalieanvändningen kan minska och i vissa fall tas bort helt. Den här studien startade med en litteraturundersökning följd av försök med ozonering och filtrering i pilotanläggningen. De första undersökningarna sammanfattades med att ozonering följt av filtrering inte gav tillräckligt bra resultat och processen behöver ett komplement för att producera ett högklassigt vatten. Undersökningen fortsatte med laboratorieanalyser för att undersöka effekterna av olika kemiska koagulanter. Resultatet visade att järnsulfat tillsammans med kalcium var ett bra alternativ och en lägre kemikaliedos kunde användas. Efter implementering av kalcium och järnsulfat till pilotanläggningen testades olika ozondoser och olika järnsulfatdoser. Det bästa resultatet erhölls då man använde sig av en ozondos på 6 mg O3/l och en järnsulfatdos på 50-60 μmol/l. Denna mängd av järnsulfat är ca 60 % lägre än den dos som används vid den konventionella reningen på Lovö vattenverk. Olika filter används i pilotanläggningen och för att förbättra resultatet provades även ett Filtralite-filter som biofilter istället för GAC-filtret. Jämförelsen mellan Filtralite-filter och GAC-filter visade på stora skillnader i parametervärden i början av studietiden. När bakteriepopulationen ökade i Filtralite-filtret blev skillnaderna mindre och i slutet av undersökningstiden var parametervärdena likartade. Det slutliga resultatet indikerar att Filtralite-filter kan vara ett bra alternativ som biofilter. / This Master thesis was made to investigate the effects of ozonation and filtration on raw water from Lake Mälaren. The study was performed in lab-scale as well as in a pilot plant at Lovö waterworks, Stockholm Water Company during spring 2004. The conventional treatment at Lovö waterworks comes with a few disadvantages, such as large consumption of chemical coagulants. The chemical consumption leads to many transports and the treatment also produces a sludge which is, in present, returned to Lake Mälaren. In 2001 a pilot plant were built at Lovö waterworks for research on new treatment processes, and ozonation followed by filtration is one of them. Ozonation has been used in Europe for several years as disinfection at the end of the drinking water treatment process. The interests of ozonation has increased significantly in recent years and today the ozonation is used in other steps in the drinking water treatment process. Except for the disinfection, ozone has other benefits such as oxidation of iron and manganese, microflocculation, reduction of taste and odour and it is also effective to reduce the water colour. The microflocculation leads to the fact that less or no coagulants need to be used in the process. This study started with a literature overview followed by experiments on ozonation and filtration in the pilot plant. After the first experiments the conclusions were that the ozonation and filtration did not reach the same results as Lovö waterworks. To continue, jar tests were made to see the effects of different coagulants. The result indicated that ferric sulphate together with calcium addition (pH-adjustment) was a good alternative. Thereby a lower coagulant dose could be used. When ferric sulphate and calcium were implemented into the pilot plant, different ozone doses and ferric sulphate doses were tested. The best results occurred when an ozone dose of 6 mg O3/l and a ferric sulphate dose of 50-60 μmol/l were used. This amount of ferric sulphate is approximately 60 % lower than that for the conventional treatment at Lovö waterworks. To produce ozone electrons are needed and energy consumption increases with approximately 66 % compared to the conventional treatment. The decrease in chemical dose and increase in energy demand gives a decrease of the total cost with 10 % compared to the conventional treatment. The results indicate that the treatment with ozonation, calcium addition and ferric sulphate as a coagulant is an alternative to the conventional treatment. Different filters were used in the pilot plant and to improve the results a Filtralite-filter was tested instead of the GAC-filter as a bio filter. When comparing Filtralite-filter with the GAC-filter there were large differences between the filters at the beginning of the study. When the bacteria population in the Filtralite-filter had started to increase the differences became less. In the end of the experimental period the filters had similar conditions and Filtralite-filter may be a good alternative as a biofilter.

Linear Alkyl benzene Sulfonic Acid (LAS) is the main ingredient of many commercial formulations for industrial and domestic synthetic detergents. The current industrial LAS production method includes sulfonation of linear alkylbenzene (LAB) with sulfur trioxide in tubular falling film reactors. In such reactors a diluted gaseous stream of SO3 and dry air, feed gas, is contacted with liquid LAB while both reactants flow co-currently downward. The reaction is highly exothermic and product quality is primarily dependent on heat removal efficiency from the reactors, and also contact time. This research project investigates a new route for the production of LAS. This new method employs SO2 oxidation over activated carbon at 25oC to SO3, followed by the extraction of the adsorbed SO3 from the activated carbon by supercritical carbon dioxide (SCCO2). The condensed phase CO2-SO3 mixture after expansion is contacted with LAB where sulfonation of this substrate occurs to yield LAS. The new route should offer lower operating temperatures and lower feed gas SO3 concentrations in the sulfonation reaction to minimize loss of LAB to side-reactions and reduce LAS contamination (that appears as unacceptable product discoloration). The laboratory set up was designed, assembled and in total 25 experiments were carried out. Over the course of experiments a number of remedial actions were taken to improve set up functionality and reaction yield. The problems needed to be tackled included feed gas moisture removal, SO2/SO3 adsorption/desorption efficiency, homogeneous mixing of reactants and reducing the SCCO2/SO3 flow rate through LAB columns. The maximum LAB/LAS conversion obtained was 3.6 % per sulfonation column. The maximum SO3 removal efficiency from activated carbon obtained was 77%. It was also found that nitrogen gas in a specific temperature range may be used as the desorbing agent in lieu of supercritical carbon dioxide with satisfactory performance. As supplementary data, the Brauner-Emmet-Teller surface area of activated carbon type BPL 6x16 from “Calgon Carbon Corporation” was measured.

<p>Electrophoresis is the migration of charged particles in a heterogeneous fluid under the influence of an electric field. This project is work toward an electrophoretic separation system on a custom CMOS chip. Modeling, fabrication, and testing of an AMI ABN 1.5 um CMOS chip for this application is discussed. The unique approach is to build the entire system using conventional CMOS integrated circuit technology, such that the separation area is fabricated on the chip with integrated control and detection circuitry. To achieve the desired functionality, a novel configuration of an electrophoresis system is implemented. In this system, instead of using only one electrode at each end of the separation area, a multitude of electrodes beneath the entire separation area are utilized, enabling better control of high electric fields using very small voltages over small areas. Electronic circuits control the position and strength of the electric field to drive the separations and to simultaneously detect the location and concentration of samples within the separation area. Ultimately, the project was successful at showing that implementing an electrophoresis system on standard CMOS is possible.</p> / Dissertation

A microfluidic lab-on-a-chip (LOC) device for in-situ synthesis of gold nano-particles was developed. The long term goal is to develop a portable hand-held diagnostic platform for monitoring water quality (e.g., detecting metal ion pollutants). The LOC consists of micro-chambers housing different reagents and samples that feed to a common reaction chamber. The reaction products are delivered to several waste chambers in a pre-defined sequence to enable reagents/ samples to flow into and out of the reaction chamber. Passive flow actuation is obtained by capillary driven flow (wicking) and dissolvable microstructures called ‘salt pillars’. The LOC does not require any external power source for actuation and the passive microvalves enable flow actuation at predefined intervals. The LOC and the dissolvable microstructures are fabricated using a combination of photolithography and soft lithography techniques. Experiments were conducted to demonstrate the variation in the valve actuation time with respect to valve position and geometric parameters. Subsequently, analytical models were developed using one dimensional linear diffusion theory. The analytical models were in good agreement with the experimental data. The microvalves were developed using various salts: polyethylene glycol, sodium chloride and sodium acetate. Synthesized in-situ in our experiments, gold nano-particles exhibit specific colorimetric and optical properties due to the surface plasmon resonance effect. These stabilized mono-disperse gold nano-particles can be coated with bio-molecular recognition motifs on their surfaces. A colorimetric peptide assay was thus developed using the intrinsic property of noble metal nano-particles. The LOC device was further developed on a paper microfluidics platform. This platform was tested successfully for synthesis of gold nano-particles using a peptide assay and using passive salt-bridge microvalves. This study proves the feasibility of a LOC device that utilizes peptide assay for synthesis of gold nano-particles in-situ. It could be highly significant in a simple portable water quality monitoring platform.

Constructd wetland system is one of the ecological engineering technologies used on wastewater treatments. In this study, we discussed the treatment efficiencies of oil refining and steel-milling wastewater by four lab-scale constructed wetland systems (0.8-m long by 0.4-m wide by 0.7-m deep), which were all filled with gravel media, and planted with Phragmites communis. The constructed wetland systems were designed into two types: free water surface (FWS) and subsurface flow (SSF) wetland systems, which were discharged with two different types of wastewater (oil refining and steel-milling). The experiments of this study were run by five stages. The experimental results showed that almost all of the contaminants could be reliably removed from wastewater by the constructed wetland systems, especially in the SSF systems. During the experiments, the second stage of the experiments had the best treatment efficiencies, in which the flowrate was controlled at 5mL/min. The hydraulic retention time (HRT) in FWS and in SSF werecalculated equal to 7.5days, and 5.36days, respectively.

Cellulose is a biodegradable, renewable, flexible, inexpensive, biopolymer which is abundantly present in nature. In spite of these inherent advantages, cellulose fibers cannot be used directly in a number of potential industrial applications because of their hydrophilic nature; a surface modification is often required to alter the surface properties of cellulose. This thesis work reports a fabrication method that results in superhydrophobic properties (contact angle (CA) > 150°) on cellulose (paper) surfaces. Superhydrophobicity was obtained by domain-selective etching of amorphous portions of the cellulose fiber in an oxygen plasma, and by subsequently coating the etched surface with a thin fluorocarbon film deposited via plasma enhanced chemical vapor deposition from a pentafluoroethane precursor. Two forms of superhydrophobicity with vastly different degrees of adhesion were obtained by varying the plasma treatment conditions, in particular the duration of oxygen etching: "roll-off" (contact angle (CA): 166.7° ± 0.9° and CA hysteresis: 3.4° ± 0.1°) and "sticky" (CA: 153.4° ± 4.7° and CA hysteresis: 149.8±5.8°) superhydrophobicity. The CA hysteresis could be tuned between the two extremes by adjusting the oxygen etching time to control the formation of nano-scale features on the cellulose fibers. The effects of fiber types (soft vs. hard wood) and paper making parameters on fabricating superhydrophobic paper were also investigated. There were no significant differences in the formation of the nano-scale features created via oxygen etching on paper substrates obtained from different fiber types and paper making parameters. Because "roll-off" superhydrophobicity is primarily determined by the nano-scale roughness, this property is therefore not significantly affected by the fiber types or paper making parameters. While the fiber type does not affect "roll-off" or "sticky" superhydrophobicity, paper making process parameters affect the structure of the paper web on the micro-scale and thus lead to variations in "sticky" superhydrophobicity. Superhydrophobic paper substrates were patterned with high surface energy ink deposited using a commercial desktop printer. The patterns could be used to manipulate the drag and extensional adhesion of water drops on the substrates. Classic 'drag' and 'extensional' adhesion expressions were used to model the behavior of water drops on basic dot and line patterns of variable dimensions. A fundamental understanding of the adhesive forces of water drops as a function of pattern shape and size was thus obtained. Based on this knowledge, patterned paper substrates were then designed and fabricated to perform simple unit operations, such as storage, transfer, mixing and merging of water drops. These basic functionalities were combined in the design of a simple two-dimensional lab-on-paper (LOP) device. Further studies of more complicated pattern shapes led to the generation of patterns that allowed directional mobility and tunable adhesion of water drops. These developments are critical for designing novel components for two-dimensional LOP devices such as flow paths, gates/diodes, junctions and drop size filters.

<p>This thesis describes the function and construction of a modular event detector system. Event detectors are used for solder joint reliability testing using electronic monitoring for short duration resistance changes during accelerated ageing and temperature cycling. Collected data is mainly used to study solder joints long-term properties. The system has three different monitoring functions: transient resistance detection, statistics process monitoring and periodic monitoring. In its present performance a total number of 384 channels can be monitored continuously. However the system can be expanded in steps of 96 channels, limited only by the capacity of the computers PCI-bus. The system is built around a PC equipped with the LabVIEW 6.1 programming environment and data acquisition cards from National Instruments. The circuit boards to be monitored are connected via adapter electronics. In the case of the superior electronic-kits project, four groups of 24 circuit boards are connected to the adapter electronics. To minimise the influence of environmental noise shielded and, where possible, twined cables are used.</p>