Microfluidic cell sorting techniques to study disease processes.

Circulating nucleated cell populations found in whole blood, including both white blood cells (leukocytes) and endothelial cells, provide an ideal platform for studies seeking to understand the disease processes for development of drugs and treatments. This thesis presents an automated microfluidic device developed for leukocyte enrichment from peripheral blood. Briefly, the device allows for complete lysis of red blood cells and comprehensive analysis of nucleated cell populations in terms of quantity and activation status. The microfluidic lysis device was used in two Sickle Cell disease (SCD) studies to understand the effect of leukocytes in the initiation of vasoocclusive crisis. Findings suggest abnormally high baseline leukocyte counts and variance in clinical expression among SCD patients. Hence, a highly favorable state for an inflammatory reaction that may lead to vasoocclusive episodes exists. To ascertain risk factors in such incidents revision of current SCD patient classification is needed

A Modular Open-Technology Device to Measure and Adjust Concentration of Sperm Samples for Cryopreservation

Repositories for aquatic germplasm can safeguard the genetic diversity of species of interest to aquaculture, research, and conservation. The development of such repositories is impeded by a lack of standardization both within laboratories and across the research community. Protocols for cryopreservation are often developed ad hoc and without close attention to variables, such as sperm concentration, that strongly affect the success and consistency of cryopreservation. The wide dissemination and use of specialized tools and devices can improve processing reliability, provide data logging, produce custom hardware to address unique problems, and save costs, time, and labor. The goal of the present work was to develop a low-cost and open-technology approach to standardize the concentration of sperm samples prior to cryopreservation. The specific objectives were to: 1) fabricate and test a peristaltic pump and optical evaluation module (POEM); 2) fabricate and test a prototype of the modular, open-technology concentration measurement and adjustment system (CMAS), which incorporated the POEM; 3) identify opportunities to extend the CMAS to microliter volumes through low-cost resin 3-D printing, and 4) identify strategies from this work that can be applied to future open fabrication efforts. The POEM and CMAS were prototyped and tested with biological samples. A relationship between optical signal and cell concentration of channel catfish (Ictalurus punctatus) sperm samples was established by linear regression. In a blind trial, cell concentrations were estimated with the POEM and correlated closely to their known concentrations (linear regression R2 = 0.9945) in a range of 1 × 108 to 4 × 109 cells/mL. The CMAS was able to estimate and adjust the concentration of a sample of the marine microalgae Tetraselmis chuii as a preparatory step for cryopreservation. To explore the possible use of the CMAS with microliter sample volumes in future work, evaluation of low-cost resin 3-D printing showed that this technology can approach conventional microfabrication techniques in feature quality and resolution. The development of the CMAS as open technology can provide opportunities for community-level standardization in cryopreservation of aquatic germplasm, invite new users, makers, and developers into the open-technology community, and increase the reach and capabilities of aquatic germplasm repositories

Proceedings of Abstracts Engineering and Computer Science Research Conference 2019

© 2019 The Author(s). This is an open-access work distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. For further details please see https://creativecommons.org/licenses/by/4.0/. Note: Keynote: Fluorescence visualisation to evaluate effectiveness of personal protective equipment for infection control is © 2019 Crown copyright and so is licensed under the Open Government Licence v3.0. Under this licence users are permitted to copy, publish, distribute and transmit the Information; adapt the Information; exploit the Information commercially and non-commercially for example, by combining it with other Information, or by including it in your own product or application. Where you do any of the above you must acknowledge the source of the Information in your product or application by including or linking to any attribution statement specified by the Information Provider(s) and, where possible, provide a link to this licence: http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/This book is the record of abstracts submitted and accepted for presentation at the Inaugural Engineering and Computer Science Research Conference held 17th April 2019 at the University of Hertfordshire, Hatfield, UK. This conference is a local event aiming at bringing together the research students, staff and eminent external guests to celebrate Engineering and Computer Science Research at the University of Hertfordshire. The ECS Research Conference aims to showcase the broad landscape of research taking place in the School of Engineering and Computer Science. The 2019 conference was articulated around three topical cross-disciplinary themes: Make and Preserve the Future; Connect the People and Cities; and Protect and Care

Fully integrated microsystem for bacterial genotyping

Methods for bacterial detection and identification has garnered renewed interest in recent years due to the infections they may cause and the antimicrobial resistances they can develop, the potential for bioterrorism threats and possible contamination of food/water supplies. Therefore, the rapid, specific and accurate detection of pathogens is crucial for the prevention of pathogen-related disease outbreaks and facilitating disease management as well as the containment of suspected contaminated food and/or water supplies. In this dissertation an integrated modular-based microfluidic system composed of a fluidic cartridge and a control instrument has been developed for bacterial pathogen detection. The integrated system can directly carry out the entire molecular processing pipeline in a single disposable fluidic cartridge and can detect sequence variations in selected genes to allow for the identification of the bacterial species and even its strain. The unique aspect of this fluidic cartridge is its modular format with a task-specific module interconnected to a fluidic motherboard to permit the selection of a material appropriate for the given processing step(s). In addition, to minimize the amount of finishing steps for assembling the fluidic cartridge, many of the functional components were produced during the polymer molding step used to create the fluidic network. The operation of the fluidic cartridge was provided by electronic, mechanical, optical and hydraulic controls located off-chip and assembled into a small footprint instrument. The fluidic cartridge was capable of performing cell lysis, solidphase extraction of genomic DNA from the whole cell lysate, continuous flow PCR amplification of specific gene fragments, continuous flow ligase detection reaction to discriminate sequence variations and universal DNA array readout, which consisted of DNA probes patterned onto a planar polymer waveguide for evanescent excitation. The performance of the fluidic system was demonstrated through its successful application to the genetic detection of bacterial pathogens, such as Escherichia coli O157:H7, Salmonella, methicillin-resistant Staphylococcus aureus and multi-drug resistant Mycobacterium tuberculosis, which are major threats for global heath. The modular system, which could successfully identify several strains of bacteria in \u3c40 min with minimal human intervention and also perform strain identification, represents a significant contribution to pathogen detection

A novel, planar, microfluidic junction for multiphase flow, exemplified through the production of fusion energy targets, encapsulated mouse neuron stem cells and multi-compartmental capsules

Droplet microfluidics has been extensively studied in last two decades and found various applications in diverse research fields. In this thesis, we focused on the development of planar microfluidic devices, and explored their utility for the formation of multiple emulsions and microparticle fabrication. Here, a geometry variant flow-focusing junction was exhibited to control the location position of droplet breakup, and eliminate the satellite droplets. Then, this junction was tested to form monodispersed, multi-cored, double-emulsion droplets with controllable core numbers (up to 35) in a stepwise emulsification mechanism. Based on the above device, three diverse applications of droplet microfluidics have been conducted: (1) the mass fabrication of polymeric microcapsules with high sphericity and concentricity for inertial confinement fusion (ICF) target fabrication; (2) the production of microgels to encapsulate mouse neuron stem cells for stem cell therapy in the treatment of spinal cord injury; and (3) the formation of squalene droplets with motility and encapsulated droplet interface bilayers for the ultimate creation of artificial cells. Through the above, the following was achieved: (1) Single-core water/polymer/oil double emulsion droplets, as ICF target shells (for which sphericity and concentricity are paramount), were produced at tunable rates up to 20Hz. The polymeric microcapsules were solidified by using photopolymerization (minimum ultra violet exposure duration is 30ms) with an average 98.43±0.68% sphericity (best 99.69%), an average 98.44±0.62% concentricity (best 99.72%) and 100% yield rate; (2) Mouse neuron stem cells were encapsulated in alginate microspheres at 1 million cells/mL alginate. MTT assays were conducted to provide evidence that the cells survived the encapsulation process with continuous proliferation in vitro; and (3) xxviii Various arrangements of encapsulated droplet interface bilayer network were observed, and the motility of double emulsion droplets was realized by continuous interfacial reactions, through which the expulsion and capture actions of squalene droplets were identified

A novel, planar, microfluidic junction for multiphase flow, exemplified through the production of fusion energy targets, encapsulated mouse neuron stem cells and multi-compartmental capsules

Droplet microfluidics has been extensively studied in last two decades and found various applications in diverse research fields. In this thesis, we focused on the development of planar microfluidic devices, and explored their utility for the formation of multiple emulsions and microparticle fabrication. Here, a geometry variant flow-focusing junction was exhibited to control the location position of droplet breakup, and eliminate the satellite droplets. Then, this junction was tested to form monodispersed, multi-cored, double-emulsion droplets with controllable core numbers (up to 35) in a stepwise emulsification mechanism. Based on the above device, three diverse applications of droplet microfluidics have been conducted: (1) the mass fabrication of polymeric microcapsules with high sphericity and concentricity for inertial confinement fusion (ICF) target fabrication; (2) the production of microgels to encapsulate mouse neuron stem cells for stem cell therapy in the treatment of spinal cord injury; and (3) the formation of squalene droplets with motility and encapsulated droplet interface bilayers for the ultimate creation of artificial cells. Through the above, the following was achieved: (1) Single-core water/polymer/oil double emulsion droplets, as ICF target shells (for which sphericity and concentricity are paramount), were produced at tunable rates up to 20Hz. The polymeric microcapsules were solidified by using photopolymerization (minimum ultra violet exposure duration is 30ms) with an average 98.43±0.68% sphericity (best 99.69%), an average 98.44±0.62% concentricity (best 99.72%) and 100% yield rate; (2) Mouse neuron stem cells were encapsulated in alginate microspheres at 1 million cells/mL alginate. MTT assays were conducted to provide evidence that the cells survived the encapsulation process with continuous proliferation in vitro; and (3) xxviii Various arrangements of encapsulated droplet interface bilayer network were observed, and the motility of double emulsion droplets was realized by continuous interfacial reactions, through which the expulsion and capture actions of squalene droplets were identified

Custom-engineered micro-habitats for characterizing rhizosphere interactions

The interactions amongst plants and microorganisms within the rhizosphere have a profound influence on global biogeochemical cycles, and a better understanding of these interactions will benefit society through improved climate change prediction, increased food security, and enhanced bioenergy production. However, the rhizosphere is one of the most complex and bio-diverse ecosystems on earth, making it difficult to parse apart specific interactions between species. This difficulty is compounded by the inability to directly visualize rhizosphere interactions through the soil. Additionally, conventional laboratory techniques do not offer real-time, high-resolution visualization or the proper environmental control to isolate and probe these interactions. A knowledge gap persists in how to design appropriate culturing platforms that allow researchers to collect spatially and temporally sensitive information about physical and chemical interactions in the rhizosphere. This dissertation addresses that gap by demonstrating the design and use of several custom-engineered micro-habitats in characterizing plant-microbe interactions. Specifically this thesis introduces novel protocols for culturing plants and microorganisms together in microfluidic platforms, pairing platforms to multi-modal imaging techniques with organelle scale resolution, and recreating the structural complexity of the rhizosphere in a microfluidic habitat. Not only does this thesis introduce novel engineered systems, but the work contained herein also goes beyond proof-of-concept experiments and demonstrates the ability of these platforms to generate hypotheses and answer outstanding biological questions

Fabrication of clog-free microfluidic cell isolation and solid-state light-emitting devices for biomedical applications

Over the past few decades, research and development on microfluidic devices, also referred to as lab-on-a-chip systems or microfluidic total analysis systems (TAS), have advanced quickly. There aren't many commercial success stories for microfluidic devices, despite the many advantages they offer, including improved analytical performance, decreased sample and reagent usage in the biomedical disciplines. From liquid biopsies, microfluidics has been used to filter out rare tumor cells from blood. Low flow rates and device clogs brought on by a single fluidic path function severely restrict processing. A novel technique was created employing multifunctional hybrid microposts with various features has effectively ensured high effective separation of rare cells from biological fluids. Furthermore, Solid-State perovskite material is synthesized, fabricated in 3D printed layers, and characterized for the need to be incorporated into fluorescence imaging of biological cells. Since effective imaging techniques are required to image the cells in a PDMS-based microfluidic device, the emission of the perovskite material shows positive signs as a fluorescent light source for identification of cells based on their emission of light.Includes bibliographical references