When paraffin wax melts it exhibits a large, relatively incompressible volume expansion. This can be used in microactuators for strong and large displacements, a rare combination among actuators. Furthermore, paraffin is inexpensive, inert and environmentally friendly, as well as easily processed and actuated. Together, these properties give paraffin actuators great potential for use in both low-cost and high-performance applications. In microfluidics, the miniaturization of various analysis systems decreases the volumes of samples and reagents needed, as well as the analysis throughput time. Using on-chip micropumps increases the efficiency of the microfluidic system, but a challenge for such pumps is the high back-pressure associated with separation, filtration or narrower channels. The objective of this thesis is to increase the understanding of paraffin in microactuators, as well as to further explore its possibilities and limitations. The main application area has been on-chip micropumps. For low-cost applications, actuators, pumps and dispensers have been fabricated in plastics and then evaluated. The dispenser is intended for on-chip storage and dispensing of liquids in a lab-on-a-chip that could be used in, e.g., point-of-care testing (POCT). For high-performance applications, metallic actuators, pumps and dispensers have been accomplished. The micropump is the world’s strongest mechanical micropump in sub-cubic centimetre size, capable of pressures of above 5 MPa. Possible applications are strong microhydraulics, on-chip chromatography, or medical microdosage systems. A limitation of paraffin is the relatively slow thermal actuation. In this thesis the thermal properties have also been turned into an advantage: Directional solidification is used to accomplish multiple stable states of the actuator displacement, withheld without any power consumption. For the future, the high-pressure capability may be improved by new designs. Optimization of speed and power consumption can be made by further work on modelling as well as on drive and control of the heating.

Objective: The aim of this study was to evaluate a new underfill-function in a POCT-instrument from HemoCue AB (Ängelholm, Sweden). The instrument is in use today among diabetes patients for self-monitoring blood glucose (SMBG). The new function is supposed to guarantee that measuring only will be performed on a sufficient sample volume to assure that the correct glucose value is received. Methods and results: Blood samples (whole blood) from 12 patients were analysed with the instrument. Measuring were performed using different volumes in the cuvette. Full cuvette, 3µL, 2µL, 1µL and a measuring on an empty cuvette. The instrument performed measurements on all volumes added to the cuvette except for the empty cuvette. The less sample volume that was used the lower glucose values were reported by the instrument. Conclusions: The new under fill-function did not work satisfactory. If such function would be more reliable it would be beneficial for the patient controlling hers/his bloodglucose provided that the testing procedure is being correctly done. This is very important because the results are often used to treat the patient.

Bacteria are the oldest, structurally simplest, and most abundant forms of life on earth. Its detection has always been a serious question since the emerging of modern science and technology. There has been a phenomenal growth in the field of real-time bacteria detection in recent years with emerging applications in a wide range of disciplines, including medical analysis, food, environment and many more. Two important analytical functions involved in bacteria detection are cell lysis and polymerase chain reaction (PCR). Cell lysis is required to break cells open to release DNA for use in PCR. PCR is required to reproduce millions of copies of the target genes to reach detection limit from a low DNA concentration. Conventionally, cell lysis and PCR are performed separately using specialized equipments. Those bulky machines consume much more than needed chemical reagents and are very time consuming. An efficient, cost-effective and portable solution involving Nanotechnology and Lab-on-a-Chip (LOC) technology was proposed. The idea was to utilize the excellent antibacterial property of surface-functionalized nanoparticles to perform cell lysis and then to perform PCR on the same LOC system without having to remove them from the solution for rapid detection of bacteria. Nanoparticles possess outstanding properties that are not seen in their bulk form due to their extremely small size. They were introduced to provide two novel methods for LOC cell lysis to overcome problems of current LOC cell lysis methods such as low efficiency, high cost and complicated fabrication process. The first method involved using poly(quaternary ammonium) functionalized gold and titanium dioxide nanoparticles which were demonstrated to be able to lyse E. coli completely in 10 minutes. The idea originated from the excellent antibacterial property of quaternary ammonium salts that people have been using for a long time. The second method involved using titanium dioxide nanoparticles and a miniaturized UV LED array. Titanium dioxide bears photocatalytic effect which generates highly reactive radicals to compromise cell membranes upon absorbing UV light in an aqueous environment. A considerable reduction of live E. coli was observed in 60 minutes. The thesis then evaluates the effect of nanoparticles on PCR to understand the roles nanoparticles play in PCR. It was found that gold and titanium dioxide nanoparticles induce PCR inhibition. How size of gold nanoparticles affected PCR was studied as well. Effective methods were discovered to suppress PCR inhibition caused by gold and titanium dioxide nanoparticles. The pioneering work paves a way for the integration of nanoparticle cell lysis and LOC PCR for rapid detection of bacteria. In the end, an integrated system involving nanoparticle cell lysis and microchip PCR was demonstrated. The prototyped system consisted of a physical microchip for both cell lysis and PCR, a temperature control system and necessary interface connections between the physical device and the temperature control system. The research explored solutions to improve PCR specificity in a microchip environment with gold nanoparticles in PCR. The system was capable of providing the same performance while reducing PCR cycling time by up to 50%. It was inexpensive and easy to be constructed without any complicated clean room fabrication processes. It can find enormous applications in water, food, environment and many more.

Tuberculosis is one of the deadliest communicable diseases in the world, and consequently remains one of the biggest global healthcare challenges. Tuberculosis is treatable and curable. However, within many low resource settings, underdeveloped medical infrastructure limits the effectiveness and accuracy of existing diagnostics. These limitations severely impede the timely diagnosis of the disease, and thus contribute to the disease spreading, developing drug resistance, and killing more individuals. There is an urgent need for an inexpensive, portable, rapid, easy-to-use point of care diagnostic that can function outside of the laboratory at the community level. Currently, there is a wide range of available tuberculosis diagnostics ranging from sputum smear microscopy to nucleic acid amplification tests. Yet, none have met every standard of the ideal point of care diagnostic. Since the World Health Organization’s endorsement of Xpert MTB/RIF in 2010, there has been a resurgence of interest in point of care diagnostic development. This investigation reviewed diagnostic development projects funded by the National Institutes of Health in 2008 and 2014 in order to examine the technologies being developed, how researchers in industrial and academic sectors are addressing this problem, and what challenges still need to be overcome. More projects in 2014 were expected to rely on sample types other than sputum and be funded than those in 2008. The results of this investigation confirm this hypothesis, and that the development of a point of care device is a multi-faceted challenge with numerous underlying issues that need to be addressed before such a device can be successfully implemented.

Bacteria are the oldest, structurally simplest, and most abundant forms of life on earth. Its detection has always been a serious question since the emerging of modern science and technology. There has been a phenomenal growth in the field of real-time bacteria detection in recent years with emerging applications in a wide range of disciplines, including medical analysis, food, environment and many more. Two important analytical functions involved in bacteria detection are cell lysis and polymerase chain reaction (PCR). Cell lysis is required to break cells open to release DNA for use in PCR. PCR is required to reproduce millions of copies of the target genes to reach detection limit from a low DNA concentration. Conventionally, cell lysis and PCR are performed separately using specialized equipments. Those bulky machines consume much more than needed chemical reagents and are very time consuming. An efficient, cost-effective and portable solution involving Nanotechnology and Lab-on-a-Chip (LOC) technology was proposed. The idea was to utilize the excellent antibacterial property of surface-functionalized nanoparticles to perform cell lysis and then to perform PCR on the same LOC system without having to remove them from the solution for rapid detection of bacteria. Nanoparticles possess outstanding properties that are not seen in their bulk form due to their extremely small size. They were introduced to provide two novel methods for LOC cell lysis to overcome problems of current LOC cell lysis methods such as low efficiency, high cost and complicated fabrication process. The first method involved using poly(quaternary ammonium) functionalized gold and titanium dioxide nanoparticles which were demonstrated to be able to lyse E. coli completely in 10 minutes. The idea originated from the excellent antibacterial property of quaternary ammonium salts that people have been using for a long time. The second method involved using titanium dioxide nanoparticles and a miniaturized UV LED array. Titanium dioxide bears photocatalytic effect which generates highly reactive radicals to compromise cell membranes upon absorbing UV light in an aqueous environment. A considerable reduction of live E. coli was observed in 60 minutes. The thesis then evaluates the effect of nanoparticles on PCR to understand the roles nanoparticles play in PCR. It was found that gold and titanium dioxide nanoparticles induce PCR inhibition. How size of gold nanoparticles affected PCR was studied as well. Effective methods were discovered to suppress PCR inhibition caused by gold and titanium dioxide nanoparticles. The pioneering work paves a way for the integration of nanoparticle cell lysis and LOC PCR for rapid detection of bacteria. In the end, an integrated system involving nanoparticle cell lysis and microchip PCR was demonstrated. The prototyped system consisted of a physical microchip for both cell lysis and PCR, a temperature control system and necessary interface connections between the physical device and the temperature control system. The research explored solutions to improve PCR specificity in a microchip environment with gold nanoparticles in PCR. The system was capable of providing the same performance while reducing PCR cycling time by up to 50%. It was inexpensive and easy to be constructed without any complicated clean room fabrication processes. It can find enormous applications in water, food, environment and many more.

O propósito desta investigação foi avaliar o desempenho funcional e a qualidade técnica de um Software-protótipo desenvolvido para a sistematização da assistência de enfermagem. Foi elaborada uma versão deste ambiente computacional específica para aplicação em dispositivo de mão móvel com interface de rede sem fio integrada possibilitando aos enfermeiros acessar e documentar dados acerca de sinais vitais, balanço hidroeletrolítrico, evolução e prescrição de enfermagem a beira do leito com transmissão de dados em tempo real. Este estudo está alicerçado no Modelo do Processo de Avaliação segundo a ISO/IEC 9126, Parte 1: Modelo de qualidade, que versa sobre qualidade externa e interna de software e a especifica em seis características denominadas: funcionalidade, confiabilidade, usabilidade, eficiência, manutenibilidade e portabilidade, as quais são subdivididas em subcaracterísticas. Foi utilizado subsídio da NBR ISO/IEC 14598 que apresenta uma visão geral do processo de avaliação de software, suas orientações e requisitos. Este estudo descritivo/exploratório foi realizado em uma instituição de ensino superior de enfermagem e duas instituições hospitalares de ensino localizadas no interior do estado de São Paulo. Os avaliadores totalizaram um número de vinte e sete e foram constituídos por oito especialistas em informática; oito enfermeiros docentes e 11 enfermeiros, sendo sete do Hospital A e quatro do Hospital B. Considerando-se a característica de modularidade e adotando o referencial proposto por Pressman (2006), realizaram-se duas etapas de avaliação: teste de unidade modular e de validação. Inicialmente, a verificação concentrou-se em cada uma das doze unidades modulares, em seguida foram avaliados na forma integrada para se proceder ao teste de validação. O desenvolvimento destas duas etapas contou com a participação individual de cada um dos especialistas e ocorreu na presença da pesquisadora. Foi elaborado um instrumento de avaliação (Anexo I) a fim de documentar os dados coletados no teste de unidade modular e com base nas características e subcaracterísticas de qualidade foram desenvolvidos instrumentos específicos para aplicação do teste de validação junto aos especialistas em informática (Anexo II a) e enfermeiros docentes e enfermeiros (Anexo II b). Os resultados demonstraram que a incorporação da tecnologia da computação móvel advinda de rede sem fio às atividades assistenciais de enfermagem proporcionou um ambiente com mobilidade para as ações e facilitou a comunicação e a documentação da assistência prestada. A avaliação dos atributos de qualidade do Software-protótipo em questão foi mensurada pelos especialistas em informática, enfermeiros docentes e enfermeiros destacando-se duas características: usabilidade e eficiência. A usabilidade foi avaliada com 100% de respostas positivas pelos docentes e enfermeiros e com 80,4% de aprovação pelos especialistas em informática evidenciando que o Software-protótipo para a sistematização da assistência de enfermagem (SAE) apresenta facilidade para inserir e obter informações e apresenta-se como um sistema dinâmico para documentar a assistência prestada. A eficiência foi aprovada com 92,3% e 87,5% de respostas positivas pelos enfermeiros docentes e especialistas em informática, respectivamente, demonstrando que uma das vantagens desta ferramenta é armazenar, processar e disponibilizar informações sobre a SAE de forma mais eficiente que a realizada manualmente. / The purpose of this investigation was to evaluate the functional performance and the technical quality of a software-prototype developed for the systematization of the nursing care. A version of this specific computational environment has been developed to be used in hand-mobile devices with integrated wireless network interface allowing the nurses to access and document data related to vital signals, hydroelectrolytic balance, evolution and nursing prescription at the point-of-care with transmission of data in real time. This study is based on Evaluation Process Model, according to ISO/IEC 9126, Part 1: Model of Quality which is versed in external and internal software quality and specifies it in six characteristics denominated: functionality, reliability, usability, efficiency, maintainability, and portability, which are subdivided in sub-characteristics. Subsidy of NBR ISO/IEC 14598 has been used, which presents a general overview of the software evaluation process, its orientations and requirements. This descriptive/exploratory study has been accomplished in a Nursing College and in two school hospital institutions in the interior of the state of Sao Paulo. It has been totaled 27 appraisers, and constituted by eight specialists on computer science; eight faculty members nurses; and 11 registered nurses - seven from Hospital A, and four from Hospital B. Considering the characteristic of modularity, and adopting the reference proposed by Pressman (2006), two stages of evaluation have been accomplished: modular unity test, and validation. Initially, the verification focused on each one of the 12 modular unities, and then they have been evaluated integrally in order to proceed the validation test. Each one of the specialists participated in the development of these two stages, which occurred in the presence of the researcher. An instrument of evaluation has been elaborated (Appendix I) in order to document the data collected in the modular unity test. Based on the characteristics and sub-characteristics of quality, specific instruments for application of the validation test have been developed along with the computer science specialists (Appendix II a), and the faculty members nurses and registered nurses (Appendix II b). The results demonstrated that the incorporation of the mobile computer technology originated from wireless network to the nursing care activities provided an environment with mobility for actions and became communication and documentation of the assistance easier. The evaluation of the quality attributes of the software-prototype was measured by the computer science specialists, faculty members nurses and registered nurses, highlighting two characteristics: usability and efficiency. The usability was evaluated, resulting 100% of positive approval among faculty members nurses, and 80.4% among computer science specialists, demonstrating that the software-prototype for the systematization of nursing care makes the action of inserting and obtaining information easy, and it is presented as a dynamic system to document the provided care. The efficiency was approved with 92.3% and 87.5% of positive answers by the faculty members nurses and computer science specialists, respectively, demonstrating that one of the advantages of this tool is to store, process, and make available information about the nursing process, more efficiently than the one made manually.

Microfluidics miniaturizes many benchtop processes and provides advantages of low cost, reduced reagent usage, process integration, and faster analyses. Microfluidic devices have been fabricated from a wide variety of materials and methods for many applications. This dissertation describes four such examples, each employing different features and fabrication methods or materials in order to achieve their respective goals. In the first example of microfluidic applications in this dissertation, thermoplastics are hot embossed to form t-shaped channels for microchip electrophoresis. These devices are used to separate six preterm birth (PTB) biomarkers and establish a limit of detection for each. The next chapter describes 3D printed devices with reversed-phase monoliths for solid-phase extraction and on-chip fluorescent labeling of PTB biomarkers. I demonstrate the optimization of the monolith and selective retention of nine PTB biomarkers, the first microchip study to perform an analysis on this entire panel. The third project describes the iterative design and fabrication of glass/polydimethylsiloxane (PDMS) devices with gold and nickel electrodes for the self-assembly of DNA nanotubes for site-selective placement of nanowires. Simple flow channels and “patch electrode” devices were successfully used, and DNA seeding was achieved on gold electrodes. Finally, a 3D printed device for cancer drug screening was developed as a replacement for one previously fabricated in PDMS. Devices of increasing complexity were fabricated, and those tested found to give good control over fluid flow for multiple inlets and valves. Although the applications and methods of these projects are varied, the work in this dissertation demonstrates the potential of microfluidics in several fields, particularly for diagnostics, therapeutics, and nanoelectronics. Furthermore, it demonstrates the importance of applying appropriate tools to each problem to gain specific advantages. Each of the described devices has the potential for increased complexity and integration, which further emphasizes the advantages of miniaturized analyses and the potential for microfluidics for analytical testing in years to come.

No description available.

<div>Pathogen identification at the point of use is critical in preventing disease transmission and enabling prompt treatment. Current rapid diagnostic tests suffer from high rates of false negatives because they are not capable of detecting the inherently low concentrations of pathogens found in early stages of infection or in environmental reservoirs. The gold standard method for timely pathogen identification is a nucleic acid amplification assay called polymerase chain reaction. Although polymerase chain reaction is extremely sensitive and specific, it requires expensive laboratory equipment and trained personnel to perform the sample preparation, cyclical heating, and amplicon analysis. Isothermal nucleic acid amplification assays are better suited for field use because they operate at a single temperature and are robust to common sample matrix inhibitors. Thus, there is a need to translate isothermal amplification assays to the point of use for rapid and sensitive detection of pathogens in complex samples.</div><div><br></div><div>Here, I outline an approach to bring laboratory-based sample preparation, assays, and analyses to the point of use via portable platforms. First, I characterize a loop-mediated isothermal amplification assay and combine it with lateral flow immunoassay for simple, colorimetric interpretation of results. Next, I optimize an ambient-temperature reagent storage method to eliminate cold-chain requirements and precision pipetting steps. I then incorporate loop-mediated isothermal amplification, lateral flow immunoassay, and reagent drying into two different integrated paperfluidic platforms and demonstrate their ability to separately detect bacteria and viruses in complex sample matrices. Finally, I couple loop-mediated isothermal amplification with particle diffusometry to optically determine pathogen presence by tracking the Brownian motion of particles added to an amplified sample. The combined loop-mediated isothermal amplification and particle diffusometry method is first characterized on a microscope and then translated to a smartphone-based platform. Each of these portable platforms are broadly applicable because they can be easily modified for identification of other pathogens at the point of use.</div>

Antibiotic resistance is now a recognized problem in global health. In attempts to find solutions to detect bacteria causing antibiotic resistance we turn to technological solutions that are miniaturized, portable and cheap. The current diagnostic procedures cannot provide correct information outside laboratory settings, at the point-of-care, within necessary time. This has led to ineffective treatment of urinary tract infections causing recurrent infections and multi-drug resistant bacteria to spread. The bacteria genes show which antibiotic that is required to eliminate disease and spread of resistance. Hence, the solution would be to perform nucleic acid testing at the point-of-care. By using new DNA amplification methods it is possible to miniaturize the diagnostic test to a so-called Lab-on-a-chip. These solutions would enable sample-in-results-out capability of the system at the point-of-care. For this to work one of the most important factors is fluorescent signal read-out from DNA amplification products. In this project the design parameters of such a read-out device was investigated with focus on image sensor sensitivity and device integration. During the project it was found that a low-cost commercial image sensor could be used to record images of a (3.76 x 2.74 mm2) micro well array of nanoliter sized PCR chambers. Different imaging artifacts appearing during sample partitioning were observed, distance dependency between sensor surface well array was investigate, and finally the image sensor function was compared to a fluorescent microscope.