Development of Smartphone dual-laser waveguide based fluorescent microscopy system using 3D printing

Nowadays cellphones are present everywhere, and along with the worldwide network of devices, the concept of mobile health monitoring is changing to reshape the biosensor market. The smartphone’s camera is a proven reliable candidate as a detector for the studies performed by various research groups. This study is a proof of concept of the Smartphone detection of two fluorescent dyes which can be used as biomarkers for point-of-care diagnostics through image processing techniques. A smartphone Xiaomi Redmi Note 4 along with two fluorescent dyes DyLight™ 405 NHS Ester and DyLight™ 633 NHS Ester are used in conjunction with two lasers Thorlabs 405 nm and 638nm. The captured pictures were analyzed using Image J. The limit of detection and dynamic range values were calculated for both dyes, 28.39 nM and 20-800 nM for DyLight™ 405 NHS Ester dye and 15.85 nM and 10-600 nM for DyLight™ 633 NHS Ester dye. Then this concept is realized by developing a cheap 3D printed POC device which uses the optical microscopy technology along with a PDMS chip. Hence, this integrated novel innovation which prioritizes accuracy and the ease of usage, can be a game changer for patients who live in countries of limited resources and can moreover aid to the impoverished people who are in dire need of medical help

Mobile Diagnosis 2.0

Mobile sensing and diagnostic capabilities are becoming extremely important for a wide range of emerging applications and fields spanning mobile health, telemedicine, point-of-care diagnostics, global health, field medicine, democratization of sensing and diagnostic tools, environmental monitoring, and citizen science, among many others. The importance of low-cost mobile technologies has been underlined during this current COVID-19 pandemic, particularly for applications such as the detection of pathogens, including bacteria and viruses, as well as for prediction and management of different diseases and disorders. This book focuses on some of these application areas and provides a timely summary of cutting-edge results and emerging technologies in these interdisciplinary fields

COPOLYMER HYDROGELS AS FULLY IMPLANTABLE OPTICAL BIOSENSORS: INVESTIGATING DESIGN PARADIGMS TO ACHIEVE LONG-TERM PRECLINICAL FUNCTION

Many diagnostic tests for disease management and overall health monitoring provide only an instantaneous measurement of the patient’s state of health, leaving intermediate fluctuations in biochemistry levels undisclosed. Often, fluid samples are collected periodically and analyzed using ex vivo assays. Diabetes is a prime example of this enigma where knowledge of blood biochemistry fluctuation patterns in real time could allow patients to make more informed treatment and lifestyle decisions. In recent years, hydrogels have been investigated as fully implantable biosensors by functionalizing them with enzymes and long-lifetime phosphors. However, maintaining a proper balance between enzyme stability and substrate transport when implanted has prevented preclinical proof of concept using this enzyme/phosphor sensing platform. This work explores the effect of matrix chemistry on enzyme stability and substrate transport and demonstrates the first noninvasive glucose tracking in porcine models by measuring luminescence lifetime instead of intensity. The first aim of this work focuses on poly(HEMA-co-AAm) matrices, characterizing them as glucose sensors in vitro and in vivo. A copolymer hydrogel containing 75:25 HEMA:AAm responded to up to 167 mg/dL of glucose in vitro and tracked real-time porcine blood glucose levels two hours after implantation, the first-reported real-time glucose tracking measuring phosphorescence lifetime using a noninvasive interrogation method. The second aim of this work employs alternative monomers such as dimethylacrylamide, N-vinyl pyrrolidone, and a 3- [Tris(trimethylsiloxy)silyl]propyl methacrylate to investigate enzyme stability and optimize substrate transport. These studies revealed that gels containing dimethylacrylamide and N-vinyl pyrrolidone provide the most enzyme stability, preserving between 60 and 93% of the original apparent activity after one week of incubation, but matrix inhomogeneities from adding silicone monomers can decrease sensor dynamic range by 56%. Finally, hybrid inorganic-organic interpenetrating network hydrogels were developed to prevent silicone phase separation in the hydrogels. These materials increased oxygen transport by up to 256% in vitro compared to pHEMA-based oxygen sensors and responded to modulated inspired oxygen in porcine models over 72 days. Hybrid sensors made with tissue-integrating inverted colloidal crystal architectures revealed minimal fibrosis in vivo with loosely woven collagen surrounding the implants, demonstrating promise for these hybrid materials as long-term implantable biosensors

Tailor-made chemical sensing platforms for decentralized healthcare and wellbeing

Aquesta tesis fa referència a la necessitat social de la implementació de sensors electroquímics en la nostra vida quotidiana a diferents nivells. Des d’un enfocament sanitari, l’ús i l’aplicació real de plataformes fàcils d’utilitzar pel propi pacient facilitarien la presa de decisions gràcies a la obtenció d’informació rellevant i monitoratge d’una malaltia. Així mateix, l’ús d’aquestes eines de manera individual, en centres de salut o inclús hospitals, ajudarien a disminuir el cost que la sanitat ha d’afrontar diàriament. Des d’un enfocament diferent, aquest tipus de sensors poden oferir també altres tipus de aplicacions, poden ser usats amb finalitats mediambientals o de seguretat. La fabricació de sensors electroquímics (amperomètrics i potenciomètrics) integrats i impresos en diferents substrats fàcils de manipular, de baix cost i robustos (com tèxtils, globus o paper) ha estat aconseguida durant aquesta tesis. L’estudi del seu rendiment analític sota la influencia de diferents situacions d’estres i en diferents fluids biològics (detectant ions en suor o glucosa en sèrum i sang) també ha estat realitzat amb èxit. Aquestes aportacions tecnològiques van dirigides a superar els reptes que la societat d’avui en dia necessita solucionar: com pot ser la sostenibilitat del sistema sanitari en una població cada vegada mes envellida; el manteniment d’una seguretat i un estat del benestar; i el control mediambiental. Aquesta tesis suposa un avenç en aquest sentit i mostra diferents solucions científiques i eines útils per aquests reptes que la societat necessita afrontar.Esta tesis hace referencia a la necesidad social de la implantación de sensores electroquímicos en nuestra vida diaria a distintos niveles. Desde un enfoque sanitario, el uso y la aplicación real de plataformas fáciles de usar mediante el propio paciente facilitarían la toma de decisiones gracias a la obtención de información relevante y monitoreo de una enfermedad. Así mismo, el uso de estas herramientas de manera individual, en centros de salud o incluso hospitales disminuiría el costo que la sanidad debe afrontar diariamente. Desde un enfoque diferente, este tipo de sensores pueden ofrecer también otro tipo de usos, pudiendo ser aplicados para fines medioambientales o de seguridad. La fabricación de sensores electroquímicos (amperométricos y potenciométricos) integrados e impresos en diferentes sustratos fáciles de manipular, de bajo costo y robustos (como textiles, globos o papel) ha sido lograda durante esta tesis. El estudio de su rendimiento analítico bajo diferentes situaciones de estrés y en diferentes fluidos biológicos (detectando iones en sudor o glucosa en suero y sangre) también ha sido realizado de manera exitosa. Estas aportaciones tecnológicas van dirigidas a superar los retos que la sociedad de hoy en día necesita solucionar: como puede ser la sostenibilidad del sistema sanitario en una población cada vez más envejecida; el mantenimiento de una seguridad y un bienestar general; y el control medioambiental. Esta tesis supone un avance en este sentido y muestra diferentes soluciones científicas y herramientas útiles para estos retos que la sociedad necesita afrontar.This thesis refers to the social need of the implementation of electrochemical sensors in our daily life at different levels. From a sanitary point of view, the use and real application of user-friendly platforms by the patient itself would facilitate the decision-making process thanks to the obtaining of relevant information and monitoring of a disease. Besides, the use of these tools individually, in health centers or even hospitals, would reduce the cost that healthcare must pay on a daily basis. In a different approach, this type of sensors can also offer other types of applications, which can be applied for environmental or safety purposes. The manufacturing of electrochemical sensors (amperometric and potentiometric) integrated and embedded on different substrates easy to manipulate, low cost and robust (such as textiles, balloons or paper) has been achieved during this thesis. The study of their analytical performance under different mechanical stress and using different biological fluids (detecting ions in sweat or glucose in serum and blood) has also been carried out successfully. These technological contributions are aimed at overcoming the challenges that today's society needs to solve: such as the sustainability of the health system in an aging population; the maintenance of security and general wellbeing; and environmental control. This thesis contributes with huge advancements to face these issues and shows different scientific solutions and useful tools for these challenges that society needs to address. This thesis refers to the social need of the implementation of electrochemical sensors in our daily life at different levels. From a sanitary point of view, the use and real application of user-friendly platforms by the patient itself would facilitate the decision-making process thanks to the obtaining of relevant information and monitoring of a disease. Besides, the use of these tools individually, in health centers or even hospitals, would reduce the cost that healthcare must pay on a daily basis. In a different approach, this type of sensors can also offer other types of applications, which can be applied for environmental or safety purposes. The manufacturing of electrochemical sensors (amperometric and potentiometric) integrated and embedded on different substrates easy to manipulate, low cost and robust (such as textiles, balloons or paper) has been achieved during this thesis. The study of their analytical performance under different mechanical stress and using different biological fluids (detecting ions in sweat or glucose in serum and blood) has also been carried out successfully. These technological contributions are aimed at overcoming the challenges that today's society needs to solve: such as the sustainability of the health system in an aging population; the maintenance of security and general wellbeing; and environmental control. This thesis contributes with huge advancements to face these issues and shows different scientific solutions and useful tools for these challenges that society needs to address

Biosensors for Diagnosis and Monitoring

Biosensor technologies have received a great amount of interest in recent decades, and this has especially been the case in recent years due to the health alert caused by the COVID-19 pandemic. The sensor platform market has grown in recent decades, and the COVID-19 outbreak has led to an increase in the demand for home diagnostics and point-of-care systems. With the evolution of biosensor technology towards portable platforms with a lower cost on-site analysis and a rapid selective and sensitive response, a larger market has opened up for this technology. The evolution of biosensor systems has the opportunity to change classic analysis towards real-time and in situ detection systems, with platforms such as point-of-care and wearables as well as implantable sensors to decentralize chemical and biological analysis, thus reducing industrial and medical costs. This book is dedicated to all the research related to biosensor technologies. Reviews, perspective articles, and research articles in different biosensing areas such as wearable sensors, point-of-care platforms, and pathogen detection for biomedical applications as well as environmental monitoring will introduce the reader to these relevant topics. This book is aimed at scientists and professionals working in the field of biosensors and also provides essential knowledge for students who want to enter the field

Density-Based Separations in Aqueous Multiphase Systems: Tools for Biological Research and Low-Cost Diagnostics

Cells often exist in heterogeneous mixtures. Density provides a property to separate several types of cells from the mixed sample in which they originate. Density-based separation methods provide a standard method to quickly separate or enrich specific populations of cells, such as lymphocytes from whole blood. This dissertation explores the use of aqueous multiphase systems (AMPS) as self-forming step-gradients in density for the separation of cells. AMPS were first discovered over a hundred years ago as aqueous two-phase systems. Density as a tool to separate cells is at least as old. Despite this long history, the work in this thesis is the first work to use AMPS to perform density-based separations on cells. This combination provides a powerful technique to separate cells and enable new testing at the point-of-care. Chapter 1 provides a short overview of aqueous multiphase systems and density-based separations of cells. Chapter 2 describes the process of taking technology, including AMPS, from a demonstration in a laboratory to a large scale evaluation in a field setting. In Chapter 3 and Appendix I, AMPS provide a means to enrich reticulocytes from whole blood as a means to grow malaria parasites. Chapter 4 and Appendix II describe the development and proof-of-prinicple of a density-based diagnostic test for sickle cell disease (SCD) using AMPS. Chapter 5 and Appendix III detail the results of a large scale field evaluation of a rapid test for SCD using AMPS in Zambia. Demonstrations of AMPS for density- and size-based separations are provided in Appendices IV and V. Appendix VI demonstrates the general usefulness of density to separate crystal polymorphs with another density-based separation method: magnetic levitation in a paramagnetic fluid. Beyond density, novel combinations of technology, such as electrochemistry and telecommunications provide opportunities for enabling global health (Appendix VII).Engineering and Applied Science

COPOLYMER HYDROGELS AS FULLY IMPLANTABLE OPTICAL BIOSENSORS: INVESTIGATING DESIGN PARADIGMS TO ACHIEVE LONG-TERM PRECLINICAL FUNCTION

Many diagnostic tests for disease management and overall health monitoring provide only an instantaneous measurement of the patient’s state of health, leaving intermediate fluctuations in biochemistry levels undisclosed. Often, fluid samples are collected periodically and analyzed using ex vivo assays. Diabetes is a prime example of this enigma where knowledge of blood biochemistry fluctuation patterns in real time could allow patients to make more informed treatment and lifestyle decisions. In recent years, hydrogels have been investigated as fully implantable biosensors by functionalizing them with enzymes and long-lifetime phosphors. However, maintaining a proper balance between enzyme stability and substrate transport when implanted has prevented preclinical proof of concept using this enzyme/phosphor sensing platform. This work explores the effect of matrix chemistry on enzyme stability and substrate transport and demonstrates the first noninvasive glucose tracking in porcine models by measuring luminescence lifetime instead of intensity. The first aim of this work focuses on poly(HEMA-co-AAm) matrices, characterizing them as glucose sensors in vitro and in vivo. A copolymer hydrogel containing 75:25 HEMA:AAm responded to up to 167 mg/dL of glucose in vitro and tracked real-time porcine blood glucose levels two hours after implantation, the first-reported real-time glucose tracking measuring phosphorescence lifetime using a noninvasive interrogation method. The second aim of this work employs alternative monomers such as dimethylacrylamide, N-vinyl pyrrolidone, and a 3- [Tris(trimethylsiloxy)silyl]propyl methacrylate to investigate enzyme stability and optimize substrate transport. These studies revealed that gels containing dimethylacrylamide and N-vinyl pyrrolidone provide the most enzyme stability, preserving between 60 and 93% of the original apparent activity after one week of incubation, but matrix inhomogeneities from adding silicone monomers can decrease sensor dynamic range by 56%. Finally, hybrid inorganic-organic interpenetrating network hydrogels were developed to prevent silicone phase separation in the hydrogels. These materials increased oxygen transport by up to 256% in vitro compared to pHEMA-based oxygen sensors and responded to modulated inspired oxygen in porcine models over 72 days. Hybrid sensors made with tissue-integrating inverted colloidal crystal architectures revealed minimal fibrosis in vivo with loosely woven collagen surrounding the implants, demonstrating promise for these hybrid materials as long-term implantable biosensors

Expanding accessibility of diagnostics through miniaturized technologies

There is a disproportionate burden of disease (measured in daily-adjusted life years, or DALYs) in low-income countries. Much of this disparity is due to infectious diseases: 53% of DALYs in Africa are due to infectious diseases, compared with only 3% in the American continents. This disparity is largely due to differences in electrical and transport infrastructure as well as access to skilled personnel and monetary resources. Current diagnostic solutions are primarily designed for high-resource settings and therefore these solutions cannot be easily translated to a lower-resource setting. In order to tackle this health disparity, new solutions must be designed specifically for a lower-resource setting. In this dissertation, we take a translational approach to engineering appropriate diagnostics for resource-limited settings. First, we develop a handheld smartphone accessory to perform an assay similar to enzyme-linked immunosorbent assay (ELISA), traditionally a laboratory-based test. In 15 minutes, it provides an objective diagnostic readout important for minimal training, while using an average of 1.6mW of power and costing only $34. We further develop the device to provide a quantitative hemoglobin measurement simultaneously with an HIV immunoassay, for use in antenatal care screening. The multiplexing two assay types that are clinically relevant has the potential to streamline workflow. While specifications can be demonstrated in the laboratory, the true test of the device must be performed in the field. We brought our smartphone accessory to three health centers in Kigali, Rwanda to be used by healthcare workers with no prior experience in ELISA. After a short 30 minute training, the healthcare workers were able to obtain diagnostic results comparable to other immunoassays run under field conditions. With a simple and user-friendly design, we sought to further expand the usage of our device as a self-testing device, having patients test themselves. Lastly, we explore manufacturable thermoplastics as a material for a microfluidic diagnostic for nucleic acid detection. The sum of this work aims to gain insight into methods of design, testing, and implementation of translational design