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OAH-Net: A Deep Neural Network for Hologram Reconstruction of Off-axis Digital Holographic Microscope
Authors:
Wei Liu,
Kerem Delikoyun,
Qianyu Chen,
Alperen Yildiz,
Si Ko Myo,
Win Sen Kuan,
John Tshon Yit Soong,
Matthew Edward Cove,
Oliver Hayden,
Hweekuan Lee
Abstract:
Off-axis digital holographic microscopy is a high-throughput, label-free imaging technology that provides three-dimensional, high-resolution information about samples, particularly useful in large-scale cellular imaging. However, the hologram reconstruction process poses a significant bottleneck for timely data analysis. To address this challenge, we propose a novel reconstruction approach that in…
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Off-axis digital holographic microscopy is a high-throughput, label-free imaging technology that provides three-dimensional, high-resolution information about samples, particularly useful in large-scale cellular imaging. However, the hologram reconstruction process poses a significant bottleneck for timely data analysis. To address this challenge, we propose a novel reconstruction approach that integrates deep learning with the physical principles of off-axis holography. We initialized part of the network weights based on the physical principle and then fine-tuned them via weakly supersized learning. Our off-axis hologram network (OAH-Net) retrieves phase and amplitude images with errors that fall within the measurement error range attributable to hardware, and its reconstruction speed significantly surpasses the microscope's acquisition rate. Crucially, OAH-Net demonstrates remarkable external generalization capabilities on unseen samples with distinct patterns and can be seamlessly integrated with other models for downstream tasks to achieve end-to-end real-time hologram analysis. This capability further expands off-axis holography's applications in both biological and medical studies.
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Submitted 17 October, 2024;
originally announced October 2024.
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Air-blood interface engineered microfluidic device to mimic shear rate gradient induced human bleeding model
Authors:
Shobhit Das,
Shilpi Pandey,
Oliver Hayden
Abstract:
Microfluidic technology has emerged as a powerful tool for studying complex biological processes with enhanced precision and control. A microfluidic chip was designed to emulate human-like microvascular networks with precise control over channel geometry and flow conditions. By simulating blood flow dynamics during bleeding events, we successfully observed the real-time interactions of platelets a…
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Microfluidic technology has emerged as a powerful tool for studying complex biological processes with enhanced precision and control. A microfluidic chip was designed to emulate human-like microvascular networks with precise control over channel geometry and flow conditions. By simulating blood flow dynamics during bleeding events, we successfully observed the real-time interactions of platelets and their aggregation induced by shear rate gradient at the wound site. Platelet dynamics is primarily influenced by physico-mechanical condition of blood vessels with pathophysiological condition of blood at close proximity of vascular injury site. This microfluidic platform facilitated the investigation of platelet adhesion, activation, and clot formation, providing a unique opportunity to study the spatiotemporal dynamics of platelet aggregation and blood clot. Our findings shed light on the intricate mechanisms underlying thrombus formation and platelet-mediated aggregation, offering a more accurate and dynamic representation of human haemostasis compared to traditional animal models. In the conventional approach, the human bleeding model is tried on mouse due to anatomy and pathological similarities between mouse and humans. This study will simplify and standardize the blood and vasculature conditions. The microfluidic-based replication of the bleeding model holds significant promise in advancing our understanding of clotting disorders and wound healing processes. Furthermore, it paves the way for targeted therapeutic interventions in managing bleeding disorders and enhancing clinical strategies for promoting efficient wound closure. Ultimately, this study demonstrates the potential of microfluidics to revolutionize haemostasis research and opens up new avenues for the development of personalized medicine approaches in the field of clotting disorders.
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Submitted 31 July, 2024;
originally announced July 2024.
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Grease the gears for a steady microfluidic flow
Authors:
Moritz Leuthner,
Oliver Hayden
Abstract:
Pumps are indispensable for analytical applications and ensure controlled fluid movement. Syringe pumps are among today_s most prevalent liquid delivery systems, especially for high-pressure, stable, low-flow-rate microfluidic applications. Due to moving mechanical parts of the assembly, regular maintenance is essential to ensure reliable operation and flow rates. However, lubrication of the mecha…
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Pumps are indispensable for analytical applications and ensure controlled fluid movement. Syringe pumps are among today_s most prevalent liquid delivery systems, especially for high-pressure, stable, low-flow-rate microfluidic applications. Due to moving mechanical parts of the assembly, regular maintenance is essential to ensure reliable operation and flow rates. However, lubrication of the mechanics is easily overlooked because the research focuses on novel analytical applications rather than on the maintenance of pumps. Here, we investigate the lubrication of the syringe pump guide rods with its effect on the flow rate stability after regular pump cleaning from contaminations. The guide rods of syringe pumps were thoroughly cleaned from any lubricant, and the flow rate for specified flowrates between 5 and 30 uL/min was measured, revealing tremendous flow rate fluctuations with a coefficient of variation (CV) value up to 0.34. In contrast, flow rate measurements of syringe pumps with lubricated guide rods show a five-fold smoother flow rate fluctuation depending on the specified flow rate with CV values below 0.07. In summary, we emphasize the awareness of lubricating moving parts of syringe pumps to achieve constant flow rates, minimize wear, and ensure the reliable operation of, for instance, accurate lab-on-a-chip workflows.
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Submitted 9 October, 2023;
originally announced October 2023.