Micro- and Nanofluidics for Bionanoparticle Analysis

Bionanoparticles such as microorganisms and exosomes are recoganized as important targets for clinical applications, food safety, and environmental monitoring. Other nanoscale biological particles, includeing liposomes, micelles, and functionalized polymeric particles are widely used in nanomedicines. The recent deveopment of microfluidic and nanofluidic technologies has enabled the separation and anslysis of these species in a lab-on-a-chip platform, while there are still many challenges to address before these analytical tools can be adopted in practice. For example, the complex matrices within which these species reside in create a high background for their detection. Their small dimension and often low concentration demand creative strategies to amplify the sensing signal and enhance the detection speed. This Special Issue aims to recruit recent discoveries and developments of micro- and nanofluidic strategies for the processing and analysis of biological nanoparticles. The collection of papers will hopefully bring out more innovative ideas and fundamental insights to overcome the hurdles faced in the separation and detection of bionanoparticles

Digital Holography Microscopy at Lab-on-a-Chip scale: novel algorithms and recording strategies

Il lavoro presentato è mirato allo sviluppo di nuove tecniche di microscopia olografica digitale (Digital Holography Microscopy, DHM), e di opportuni algoritmi numerici per lo studio di biomateriali in ambiente microfluidico. Nello specifico vengono affrontate due problematiche di imaging particolarmente rilevanti nello studio di sistemi Lab-on-a-Chip (LoC). Dapprima è stato studiato il problema della microscopia quantitativa di oggetti biologici osservati attraverso mezzi complessi, come soluzioni torbide e substrati diffondenti, dove la formazione dell’immagine è ostacolata da processi di scattering. Lo studio condotto è stato mirato all’analisi di processi di diffusione da layer statico e da mezzo liquido di tipo colloidale, in regime quasi-statico e dinamico. Sono stati sviluppati a tale scopo dei metodi di registrazione e nuovi algoritmi di ricostruzione dell’immagine olografica (Multi-Look Digital Holography, MLDH) che consentono di fornire un imaging quantitativo dei campioni in esame. Di particolare interesse è il caso di volumi di liquido costituiti da globuli rossi: nel lavoro presentato viene dimostrata la possibilità di studiare, mediante MLDH, processi di adesione cellulare di materiale biologico situato in presenza di flussi di globuli rossi ad alta concentrazione. La possibilità di visualizzare e analizzare quantitativamente materiale biologico all’interno di un capillare o una vena, compensando l’effetto di diffusione del sangue, potrebbe in futuro consentire di studiare la formazione all’interno del vaso di coaguli e placche di colesterolo, sintomatici dell’insorgere di malattie cardiache. La stessa tecnica è in grado di recuperare l’informazione distorta a causa della presenza all’interno del canale di ostacoli statici o quasi-statici (dovuti alla formazione di bio-film o sospensioni batteriche, o causata da processi di fabbricazione del canale microfluidico), aumentando così notevolmente la varietà dei processi biologici analizzabili su piattaforme LoC. Nel lavoro viene anche dimostrato come la presenza di un mezzo torbido possa essere sfruttata vantaggiosamente al fine di migliorare la qualità dell’immagine in sistemi di imaging basati su luce coerente. Parallelamente è stata messa a punto una tecnica interferometrica che, sfruttando il movimento dei campioni nei canali microfluidici, consente di sostituire un sensore convenzionale 2D con un sensore lineare, più compatto e integrabile a bordo del chip, e capace di fornire prestazioni superiori in termini di velocità di acquisizione. Il lavoro presentato descrive il processo di sintesi di un nuovo tipo di ologramma (Space-Time Digital Hologram, STDH), che consente di ottenere un Field-of-View (FoV) illimitato nella direzione del flusso e, quindi, di superare il trade-off esistente tra fattore di ingrandimento e FoV, comune ad ogni tecnica di microscopia convenzionale. Viene inoltre dimostrato che un STDH mantiene le caratteristiche e i vantaggi di un ologramma digitale standard, quali la focalizzazione numerica flessibile, che permette di analizzare contemporaneamente tutti gli oggetti presenti in un volume di liquido, e la possibilità di estrarre la segnatura di fase degli stessi

Micro/nano devices for blood analysis

[Excerpt] The development of microdevices for blood analysis is an interdisciplinary subject that demandsan integration of several research fields such as biotechnology, medicine, chemistry, informatics, optics,electronics, mechanics, and micro/nanotechnologies.Over the last few decades, there has been a notably fast development in the miniaturization ofmechanical microdevices, later known as microelectromechanical systems (MEMS), which combineelectrical and mechanical components at a microscale level. The integration of microflow and opticalcomponents in MEMS microdevices, as well as the development of micropumps and microvalves,have promoted the interest of several research fields dealing with fluid flow and transport phenomenahappening at microscale devices. [...

Integrated manipulation, detection and counting of cells in biofluids

The manipulation, trapping, detection and counting of cells in biological fluids is of critical importance to the areas of disease diagnosis, drug delivery and genomic applications in biomedical research. In recent times, this research has focussed on utilising the superior metering, separation, routing, mixing and incubation capabilities of centrifugal microfluidic “Lab on a Disk” (LOAD) technologies to tackle the challenge of handling numerous types of cells, proteins, genes and their reagents simultaneously. Furthermore, integrated optical detection systems are being developed in parallel to the aforementioned microfluidic technologies, to facilitate the accurate and inexpensive detection, imaging and counting of cells. This thesis describes a number of novel centrifugal microfluidic approaches towards the separation, capture and detection of white blood cells from whole blood. Firstly, a thorough review of the state-of-the art research in the areas of centrifugo-microfluidic cell handling and detection is outlined. Secondly, a series of physical size filtration and microcontact printing approaches for the capture and detection of biomimetic particles are described. Finally, the author assesses the suitability of sol-gel materials for waveguiding applications on disposable LOAD platforms and outlines areas of future work that would build upon the research undertaken in this thesis

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

Extracellular Vesicle Profiling Towards Disease Detection by Using Micro/Nano-fluidic Devices

Based on the American Cancer Society, in 2020 there will be an estimated 1.8 million new cancer cases diagnosed and about 0.6 million cancer patients will die because of cancer. Meanwhile, millions of people in the United State do not have proper treatment regimens, early diagnosis opportunities, and continuously monitoring recurrence. Point-of-care testing (POCT) is one possible solution to reduce the cost while maintaining disease management capabilities. To achieve the potential of POCT, extracellular vesicles (EVs) have garnered much attention because of the ability to secure these biomarkers in a minimially invasive manner and also, the wealth of information they contain to realize full management of disease for cancer patients. To facilitiate the realization of POCT for cancer diseases, microfluidic and nanofluidic technologies have been recognized as possessing high efficiency, throughput, accuracy, and low-cost to replace conventional benchtop experiments and realized POCT for oncology.We successfully developed a microfluidic system, ExoSearch chip, for cancer diagnosis with on-chip EV isolation using immune-magnetic beads. The ExoSearch chip also included features of continuous flow and customizable capture antibodies, which makes the ExoSearch chip able to target different types of cancer by targeting the appropriate antigen. Three ovarian cancer-related biomarkers, CA-125, EpCAM, and CD24, which reside on the surface of EVs, were analyzed to provide accurate results (p = 0.0001, 0.0009, 0.003, respectively). Furthermore, 3-dimensional (3D) printing technology was used for microfluidic fabrication to boost prototyping capabilities. The EVs were also able to be collected, engineered, and released for immunotherapy. The EVs were modified by cancer-related peptides and were able to trigger an immune response and activate the cytotoxic T cell (CTL) to target tumor cells. Both in vitro and ex-vivo experiments were performed to evaluate the engineered EVs for immunotherapy. Our lab also developed an EV-MAP chip made from thermoplastic materials, which lifted the possibility of chip mass production for clinical applications that require one-time use devices, more binding sites, and faster sample processing rate, which increased the binding capacity and also the sampling efficiency. The EV-MAP chip was used for ovarian cancer plasma sample characterization and for radiation injury diagnosis. The EV related miRNA, miR-92a-3p, and miR-204-5p were also targeted as biomarkers for exposure to ionizing radiation. The combination of total protein expression and miRNA expression indicated that the CD8 expressing EV subpopulation showed upregulated numbers of CD8 expressing EVs without significant changes in protein expression and the CD8 subpopulation did not show major expression of miR-92a-3p or miR-204-5p. Current enumeration platforms for EVs consist of nanoparticle tracking analysis (NTA), electron microscopy (EM), high-resolution flow cytometry (hFC) and are used for both EV size distribution and concentration analysis. However, disadvantages of these technologies include large sample volume requirements, vibration-free operation, temperature consistency, and extensive software analysis, which have reduced the EV translation capacity. We have developed an in-plane nano-Coulter counter (nCC) device for enumerating EVs rapidly. With the concept of resistive pulse sensing (RPS), an electrical signal is generated for each EV when the EV travels through the nanopore. By understanding the electrical signals' frequency and amplitude, both the concentration and size distribution profiles can be collected for each EV sample quickly and efficiently. The nCC chip can also be used for EV enumeration for SARS-CoV-2 viral particle counting to determine viral load of SARS-CoV-2 viral particles enriched from biological samples to screen the infectious status of patients suspected of possessing COVID-19

MEMS Technology for Biomedical Imaging Applications

Biomedical imaging is the key technique and process to create informative images of the human body or other organic structures for clinical purposes or medical science. Micro-electro-mechanical systems (MEMS) technology has demonstrated enormous potential in biomedical imaging applications due to its outstanding advantages of, for instance, miniaturization, high speed, higher resolution, and convenience of batch fabrication. There are many advancements and breakthroughs developing in the academic community, and there are a few challenges raised accordingly upon the designs, structures, fabrication, integration, and applications of MEMS for all kinds of biomedical imaging. This Special Issue aims to collate and showcase research papers, short commutations, perspectives, and insightful review articles from esteemed colleagues that demonstrate: (1) original works on the topic of MEMS components or devices based on various kinds of mechanisms for biomedical imaging; and (2) new developments and potentials of applying MEMS technology of any kind in biomedical imaging. The objective of this special session is to provide insightful information regarding the technological advancements for the researchers in the community

Development and evaluation of a process to isolate picolitre compartments of a microfluidic bioassay to search for new microbial compounds

Verglichen mit etablierten industriellen Hochdurchsatz-Anlagen entwickelten sich mikrofluidische, emulsionsbasierte Tropfensysteme in den letzten Jahren zu einer günstigen Alternative. Jedoch ist es derzeit nicht möglich, einzelne Tropfen im Pikoliter-Volumenbereich aus einer Vielzahl anderer Proben für anschließende Analysen zu isolieren. Diese Arbeit präsentiert ein Verfahren, um Tropfen mittels fluidischer Kanalstrukturen zu isolieren und über einen Brechungsindex-Sensor zu detektieren. Das erzeugte Signal ermöglicht eine automatisierte Einzelablage von Tropfen in adressierbare Kompartimente, wie beispielsweise in Petrischalen oder Mikrotiterplatten. Ergebnisse zeigen eine effektive Extraktion einzelner Tropfenfraktionen. Dennoch bedarf es einer kontinuierlichen Überwachung von Prozessparametern wie Flussrate und Tropfendurchsatz, um eine Trennung der einzelnen Tropfen zu gewährleisten. Gleichwohl bietet dieses online-Verfahren eine Möglichkeit, allgemeine Laborprotokolle und Analysetechniken mit Tropfenbasierter Mikrofluidik zu vereinen.Microfluidic emulsion-based droplet systems have a great potential for inexpensive ultrahigh-throughput experimentation. Yet, picking single/unique picolitre-sized droplets of interest out of million others for upscaling and deeper analysis is still a fundamental limitation. In order to overcome this missing gap, a system was developed in which sorted droplets of interest are redirected into a capillary and pass through a refraction-based sensor before exiting. The signal of each droplet triggers a positioning algorithm that ultimately places the flowing droplet into an addressable compartment in either a microtiter plate or a Petri dish. Results indicate the effective isolation of a fraction of single droplets. However, it is crucial to monitor the droplet frequencies and flow rates, as multiple droplets can be deposited together if sorted within a short time interval. Nevertheless, the possibility to isolate a significant fraction of single droplets without disrupting the experimental workflow provides a necessary feature for interfacing droplet microfluidics with standard laboratory analysis and processing

3rd International Workshop on Instrumentation for Planetary Missions : October 24–27, 2016, Pasadena, California

The purpose of this workshop is to provide a forum for collaboration, exchange of ideas and information, and discussions in the area of the instruments, subsystems, and other payload-related technologies needed to address planetary science questions. The agenda will compose a broad survey of the current state-of-the-art and emerging capabilities in instrumentation available for future planetary missions.Universities Space Research Association (USRA); Lunar and Planetary Institute (LPI); Jet Propulsion Laboratory (JPL)Conveners: Sabrina Feldman, Jet Propulsion Laboratory, David Beaty, Jet Propulsion Laboratory ; Science Organizing Committee: Carlton Allen, Johnson Space Center (retired) [and 12 others

Capillary Microfluidic Chips for Point-of-Care Testing:from Research Tools to Decentralized Medical Diagnostics

Research on microfluidic devices for biological analysis has progressed sufficiently to be developed into point-of-care diagnostics products. The goal of this thesis is to improve multiple aspects of capillary-driven microfluidic devices. In particular, the objective is to provide devices with a fast time to result, that are simple to use (one-step), that can be portable, that accept a variety of samples, that operate reliably, that provide a range of detection signals, that are mass manufacturable at lost cost, and that are able to detect medically relevant biological molecules. First, we survey the evolution of microfluidic research into portable medical diagnostic devices. By looking at several gaps and opportunities in current medical diagnostics, we provide an overview of research topics that have the potential to shape the next generation of point-of-care diagnostics. Specifically we explain technologies in the order of sample interacting with different components of a device. We investigate the materials, surface treatments, sample processing, microfluidic elements (such as valves, pumps and mixers), receptors and analytes and the integration of these components into a device that might conceivably leave the laboratory for the hands of consumers. The knowledge of what is important in a point-of-care diagnostics device was used to develop a proof of concept. One of the main challenges is to make microfluidics easy to use by incorporating reagents and microfluidic elements. We integrated a number of functional elements on a chip such as a sample collector, delay valves, flow resistors, a deposition zone for detection antibodies (dAbs), a reaction chamber sealed with a polydimethylsiloxane (PDMS) substrate, and a capillary pump and vents. We further incorporated capture antibodies (cAbs), detection antibodies (dAbs) and analyte molecules for making one-step immunoassays. The integrated microfluidic chip requires only the addition of sample to trigger a sequence of events controlled by capillary forces to detect C-reactive protein (CRP), a general inflammation and cardiac marker, at a concentration of 1 ng mL-1 within 14 min using only 5 µL of human serum. The proof-of-concept is extended to easily modify several assay parameters such as the flow rates and the volumes of samples for tests, and the type of reagents and receptors for analytes. The multiparametric microfluidic chip is capable of analyzing 20 µL of human serum in 6 parallel flow paths in a range of flow rates with filling times from 10 minutes to 72 minutes. The asymmetric release of dAbs in a stream of human serum is compensated by a Dean flow mixer. Sample is equally split into 6 reaction chambers connected to flow resistances that vary flow rates, and the kinetics of capture of analyte-dAb complexes. The increased incubation time leads to a fourfold increase in detection signal in the reaction chamber with the longer incubation time. Furthermore, integrating reagents and controlling their release is essential for simple and accurate point-of-care diagnostic devices. We developed reagent integrators (RIs) to release small amounts of dried reagents (ng quantities and less) into microliters of sample. Typical RIs are composed of an inlet splitting into a central reagent channel, with a high hydraulic resistance, and two diluter channels. Reagents spotted in the central channel reconstitute in sample during filling and merge at the end of the RI with a dilution factor corresponding to the relative hydraulic resistance of the channels forming the RI. RIs are simple to integrate in lateral flow assays and provide a great degree of control over reagent integration and dissolution. Finally, the one-step capillary-driven microfluidic chips have the ability to not only detect a variety of proteins, but also to detect nucleic acids for molecular diagnostics. These devices, especially if manufactured in low cost plastic and used with portable fluorescence readers, have the potential to identify a wide variety of health conditions and to enable truly decentralized medical diagnostics