Low-cost portable microscopy systems for biomedical imaging and healthcare applications

In recent years, the development of low-cost portable microscopes (LPMs) has opened new possibilities for disease detection and biomedical research, especially in resource-limited areas. Despite these advancements, the majority of existing LPMs are hampered by sophisticated optical and mechanical designs, require extensive post-data analysis, and are often tailored for specific biomedical applications, limiting their broader utility. Furthermore, creating an optical-sectioning microscope that is both compact and cost effective presents a significant challenge. Addressing these critical gaps, this PhD study aims to: (1) develop a universally applicable LPM featuring a simplified mechanical and optical design for real-time biomedical imaging analysis, and (2) design a novel, smartphone-based optical sectioning microscope that is both compact and affordable. These objectives are driven by the need to enhance accessibility to quality diagnostic tools in varied settings, promising a significant leap forward in the democratization of biomedical imaging technologies. With 3D printing, optimised optical design, and AI techniques, we can develop LPM’s real time analysis functionality. I conducted a literature review on LPMs and related applications in my study and implemented two low-cost prototype microscopes and one theoretical study. 1) The first project is a portable AI fluorescence microscope based on a webcam and the NVIDIA Jetson Nano (NJN) with real-time analysis functionality. The system was 3D printed, weighing ~250 grams with a size of 145mm × 172 mm × 144 mm (L×W×H) and costing ~$400. It achieves a physical magnification of ×5 and can resolve 228.1 lp/mm USAF features. The system can recognise and count fluorescent beads and human red blood cells (RBCs). 2) I developed a smartphone-based optical sectioning microscope using the HiLo technique. To our knowledge, it is the first smartphone-based HiLo microscope that offers low-cost optical-sectioned widefield imaging. It has a 571.5 μm telecentric scanning range and an 11.7 μm axial resolution. I successfully used it to realize optical sectioning imaging of fluorescent beads. For this system, I developed a new low-cost HiLo microscopy technique using microlens arrays (MLAs) with incoherent light-emitting diode (LED) light sources. I conducted a numerical simulation study assessing the integration of uncoherent LEDs and MLAs for a low-cost HiLo system. The MLA can generate structured illumination in HiLo. How the MLA’s geometry structure and physical parameters affect the image performance were discussed in detail. This PhD thesis explores the advancement of low-cost portable microscopes (LPMs) through the integration of 3D printing, optimized optical design, and artificial intelligence (AI) techniques to enhance their real-time analysis capabilities. The research involved a comprehensive literature review on LPMs and their applications, leading to the development of two innovative prototype LPMs, alongside a theoretical study. These works contribute significantly to the field by not only addressing the technical and financial barriers associated with advanced microscopy but also by laying the groundwork for future innovations in portable and accessible biomedical imaging. Through its focus on simplification, affordability, and practicality, the research holds promise for substantially expanding the reach and impact of diagnostic imaging technologies, especially in those resource-limited areas.In recent years, the development of low-cost portable microscopes (LPMs) has opened new possibilities for disease detection and biomedical research, especially in resource-limited areas. Despite these advancements, the majority of existing LPMs are hampered by sophisticated optical and mechanical designs, require extensive post-data analysis, and are often tailored for specific biomedical applications, limiting their broader utility. Furthermore, creating an optical-sectioning microscope that is both compact and cost effective presents a significant challenge. Addressing these critical gaps, this PhD study aims to: (1) develop a universally applicable LPM featuring a simplified mechanical and optical design for real-time biomedical imaging analysis, and (2) design a novel, smartphone-based optical sectioning microscope that is both compact and affordable. These objectives are driven by the need to enhance accessibility to quality diagnostic tools in varied settings, promising a significant leap forward in the democratization of biomedical imaging technologies. With 3D printing, optimised optical design, and AI techniques, we can develop LPM’s real time analysis functionality. I conducted a literature review on LPMs and related applications in my study and implemented two low-cost prototype microscopes and one theoretical study. 1) The first project is a portable AI fluorescence microscope based on a webcam and the NVIDIA Jetson Nano (NJN) with real-time analysis functionality. The system was 3D printed, weighing ~250 grams with a size of 145mm × 172 mm × 144 mm (L×W×H) and costing ~$400. It achieves a physical magnification of ×5 and can resolve 228.1 lp/mm USAF features. The system can recognise and count fluorescent beads and human red blood cells (RBCs). 2) I developed a smartphone-based optical sectioning microscope using the HiLo technique. To our knowledge, it is the first smartphone-based HiLo microscope that offers low-cost optical-sectioned widefield imaging. It has a 571.5 μm telecentric scanning range and an 11.7 μm axial resolution. I successfully used it to realize optical sectioning imaging of fluorescent beads. For this system, I developed a new low-cost HiLo microscopy technique using microlens arrays (MLAs) with incoherent light-emitting diode (LED) light sources. I conducted a numerical simulation study assessing the integration of uncoherent LEDs and MLAs for a low-cost HiLo system. The MLA can generate structured illumination in HiLo. How the MLA’s geometry structure and physical parameters affect the image performance were discussed in detail. This PhD thesis explores the advancement of low-cost portable microscopes (LPMs) through the integration of 3D printing, optimized optical design, and artificial intelligence (AI) techniques to enhance their real-time analysis capabilities. The research involved a comprehensive literature review on LPMs and their applications, leading to the development of two innovative prototype LPMs, alongside a theoretical study. These works contribute significantly to the field by not only addressing the technical and financial barriers associated with advanced microscopy but also by laying the groundwork for future innovations in portable and accessible biomedical imaging. Through its focus on simplification, affordability, and practicality, the research holds promise for substantially expanding the reach and impact of diagnostic imaging technologies, especially in those resource-limited areas

Bidirectional Interactions Between Mitochondrial Function and Cell Mechanics

Energetic and structural maintenance are both critical to cellular homeostasis, and clinical disease is often characterized by alterations in both of these realms. While the manifestation of pathology in each of these fields has been extensively studied, little research has been done to characterize basic, direct interactions between mitochondrial function and cell mechanics. The experiments described in this dissertation endeavored to address that gap, first by investigating the cytoskeletal and mechanical effects of mitochondrial dysfunction and then by considering the mitochondrial consequences of cytoarchitectural breakdown. Mechanical integrity of the cell following mitochondrial dysfunction was investigated through multiple experimental platforms, including the quartz crystal microbalance with dissipation (QCM-D). Early work thus focused on improving the suitability of QCM-D for cell experimentation by developing a method of covalently conjugating fibronectin to QCM-D sensors. We then subjected cells to mitochondrial toxins in order to address whether and how mitochondrial dysfunction affects cell mechanics and the cytoskeleton. Cells showed characteristic rounding after long-term exposure to rotenone, an inhibitor of complex I of the mitochondrial respiratory chain. Since mitochondrial dysfunction can also be caused by genetic defects in the mitochondrial DNA (mtDNA), we also studied the cytoskeletal and mechanical variations in cells heteroplasmic for the m.3243A\u3eG mutation. We found a conserved, nonmonotonic relationship between m.3243A\u3eG heteroplasmy and cell mechanics, originating in expression of actin-related genes and persisting at the levels of protein production, cytoskeletal structure, and single cell stiffness. The second half of the dissertation considered how cytoarchitectural breakdown influences mitochondria. We first developed a novel tool for tracking individual mitochondria throughout entire cells, and then used this method to demonstrate that microtubule and microfilament depolymerization affect mitochondrial motility in opposing ways. Another set of experiments found that cytoskeletal breakdown significantly decreased mitochondrial respiration, which sometimes only occurred when mitochondria were pre-stressed by increased demands of calcium maintenance. Together, these studies highlight direct, bidirectional interactions between mitochondrial function and cell mechanics. These findings will inform future mechanistic studies focused on a comprehensive understanding of human disease at the cellular level, which will hopefully contributing to advancing development of therapeutics

Life Sciences Program Tasks and Bibliography

This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1995. Additionally, this inaugural edition of the Task Book includes information for FY 1994 programs. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive Internet web pag

From Ecological Epitome to Medical Model: An investigation into Applications for the use of Daphnia in Heart Science.

The primary aim of this research was to determine whether Daphnia might become a model for cardiovascular concentration-response trials. This would provide a high throughput means of testing cardiac therapeutics without resort to small mammal trials. We found Daphnia are inappropriate in this context due to high population variance and sensitivity to small, subtle, environmental changes. A new aim was developed to determine whether beat-to-beat variation could be correlated with an individual’s response to toxic insult. Further, to develop more accurate and efficient means of gathering heart rhythm data by recording heart movement from whole live Daphnia. This opens the way to individualising cardio therapeutics; by correlating the stability of individual hearts with response to cardiac insult, regression analysis provides a means of finding a prediction tool. Daphnia are a convenient example here, but successful scoring systems might also be applied to the human heart via analysis of ECG readouts. Collecting signals from whole live Daphnia did not fulfil the goal of gathering heart data as this instead recorded limb movement. However, this provides a means of improving toxicology testing in aquatic ecology. This thesis offers three contributions to knowledge: 1. Daphnia are an inappropriate model for cardiovascular therapeutic dose-response trials due to extreme environmental sensitivities. 2. Baseline heart rhythm can be correlated with paired response to cardiac insult, with significance at the 0.01 alpha level, using an adjusted version of the Lyapnov equation; Finite Time Growth (Wessel, 2010). However, this is only if population variation is adequate. It is better applied to a natural in situ population than a homegenic lab population. 3. A novel technique for measuring Daphnia electromechanical movement records feeding limbs rather than the heart. This offers a novel and more efficient technique for aquatic ecotoxicology, where visual observation or films of the same are currently used