| 1. |
- Abazajian, Kevork, et al.
(författare)
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CMB-S4 : Forecasting Constraints on Primordial Gravitational Waves
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 926:1
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Tidskriftsartikel (refereegranskat)abstract
- CMB-S4—the next-generation ground-based cosmic microwave background (CMB) experiment—is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the universe. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semianalytic projection tool, targeted explicitly toward optimizing constraints on the tensor-to-scalar ratio, r, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2–3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments, given a desired scientific goal. To form a closed-loop process, we couple this semianalytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for r > 0.003 at greater than 5σ, or in the absence of a detection, of reaching an upper limit of r < 0.001 at 95% CL.
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| 2. |
- Comina Bellido, German
(författare)
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Autonomous Lab-on-a-chip: solutions and fast prototyping tools
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, solutions for the development of autonomous Lab-on-a-chip (LOC), and 3D printing for fast prototyping of LOC devices are investigated. Lab-on-a-chip devices integrate analytical systems and conditioning processes in a compact package. Small sample volume, disposability, ability to perform complex analysis and performance comparable to classical instrumentation are characteristics that make LOCs excellent candidates for biomedical applications, environmental monitoring and food analysis. Classical LOC configurations usually require additional elements such as pumps, valves, fluidics interface connectors, and even pneumatic control to operate. Also, in most cases, a computer-capable device, or standalone control system, is needed in connection with the measurements. Autonomous LOCs avoid the use of additional components, as they are designed to integrate all necessary parts in one design. Cell phones are the most wide spread computer capable devices, and the advantage to exploit them as analytical instruments is obvious. They have been used in connection with microfluidic LOC measurements, typically using accessory dongles. To connect to the LOCs, in some cases, even permanent modifications of the phones were required. In this thesis, direct coupling to cell phone readout, without accessories beyond the LOC, has been investigated. Autonomous LOC development demands extensive time and resources for prototype optimization. Classical LOC fabrication methods, which are based on lithographic microfabrication, require special equipment and facilities. Additionally, the fabrication of 3D structures require multiple fabrication steps with numerous intermediate alignment. In this thesis, commercial-grade, low-cost 3D printers have been investigated as fast LOC prototyping platforms. The printers (Miicraft® DLP-3D printer and Formlabs Inc. Form+1) are based on Stereo Lithography (SLA). In this additive fabrication technique, a 3D computer model of the LOC is designed. Later, the 3D model is sliced in 2D patterns along the height of the design, and each of the 2D patterns is projected through the printer transparent tank bottom, which contains a liquid photocurable resin. Each exposure cures a thin layer of the resin, and the procedure is repeated adding layer after layer until the 3D printout is completed. With this technique it was possible to obtain real 3D LOC structures with unlimited number of 3D features in one step, within the hour, and at low-cost for prototyping, which constitutes a superb tool for fast and affordable sophistication of LOC architecture. The process was extended in this thesis to another area of complex and costly development: the manufacture of optical components. It was shown that optical components with arbitrary geometry could be obtained within the hour and typically for less than 1€/prototype. The first use of the technique was to produce templates for classical LOCs of polydimethylsiloxane (PDMS) on glass. The procedure was the first, to our knowledge, implemented with consumer grade printers, and included a demonstration of template fabrication for the development of a multilayer PDMS-LOC for colorimetric detection of glucose. The technique then evolved to the complete replacement of the PDMS stage, by conceiving the LOC architecture as a single monolithic printout. This concept was coined Unibody LOC (ULOC) and was used in this thesis for the development of all the autonomous Lab on a Chip solutions. Numerous solutions towards autonomous LOCs were developed such as: multidimensional adaptors that connect for example 1.6mm diameter tubing directly to 50μm wide microfluidic channels, several on plane and multilayer mixers, hybrid ULOC with paper channels, finger-pumps, check-valves, optical couplers and 3D printed optics. Time-dependent optical response bio-chemical reactions were identified as key to implement the link between autonomous LOC with cell phones without other accessories, and relying on ambient light as illumination. Such approach improves the analytical resolution of a colorimetric measurement using essentially the same camera. Finally, all those solutions were integrated to develop a chemical sensing interface for universal cell phone readout, and a 3D printed device for quantitative enzymatic detection using cell phones.
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| 3. |
- Meng, Lingyin, 1991-
(författare)
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Tailoring Conducting Polymer Interface for Sensing and Biosensing
- 2020
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- The routine measurement of significant physiological and biochemical parameters has become increasingly important for health monitoring especially in the cases of elderly people, infants, patients with chronic diseases, athletes and soldiers etc. Monitoring is used to assess both physical fitness level and for disease diagnosis and treatment. Considerable attention has been paid to electrochemical sensors and biosensors as point-of-care diagnostic devices for healthcare management because of their fast response, low-cost, high specificity and ease of operation. The analytical performance of such devices is significantly driven by the high-quality sensing interface, involving signal transduction at the transducer interface and efficient coupling of biomolecules at the transducer bio-interface for specific analyte recognition. The discovery of functional and structured materials, such as metallic and carbon nanomaterials (e.g. gold and graphene), has facilitated the construction of high-performance transducer interfaces which benefit from their unique physicochemical properties. Further exploration of advanced materials remains highly attractive to achieve well-designed and tailored interfaces for electrochemical sensing and biosensing driven by the emerging needs and demands of the “Internet of Things” and wearable sensors.Conducting polymers (CPs) are emerging functional polymers with extraordinary redox reversibility, electronic/ionic conductivity and mechanical properties, and show considerable potential as a transducer material in sensing and biosensing. While the intrinsic electrocatalytic property of the CPs is limited, especially for the bulk polymer, tailoring of CPs with controlled structure and efficient dopants could improve the electrochemical performance of a transducer interface by delivering a larger surface area and enhanced electrocatalytic property. In addition, the rich synthetic chemistry of CPs endows them with versatile functional groups to modulate the interfacial properties of the polymer for effective biomolecule coupling, thus bridging organic electronics and bioelectrochemistry. Moreover, the soft-material characteristics of CPs enable their use for the development of flexible and wearable sensing platforms which are inexpensive and light-weight, compared to conventional rigid materials, such as carbons, metals and semiconductors.This thesis focuses on the exploration of CPs for electrochemical sensing and biosensing with improved sensitivity, selectivity and stability by tailoring CP interfaces at different levels, including the CP-based transduction interface, CP-based bio-interface and CP-based device interface.First, we demonstrate different strategies for tailoring the physicochemical properties of poly (3,4-ethylenedioxythiophene) (PEDOT) beyond its intrinsic properties, via charge effects, structural effects and by the use of hybrid materials, as a CP-based transduction interface to improve sensing performance of various analytes. 1) A positively-charged PEDOT interface, and a negatively-charged carboxylic-acid-functionalised PEDOT (PEDOT:COOH) interface were developed to modulate the electrode kinetics for oppositely-charged analytes, e.g. negatively-charged nicotinamide adenine dinucleotide (NADH) and positively-charged dopamine (DA), respectively. These interfaces displayed high sensitivity and wide linear range towards the analytes due to the electrostatic attraction effect. 2) Various structured PEDOT including porous microspheres and nanofibres were synthesised via hard-template and soft-template methods, respectively, and were employed as building blocks for a hierarchical PEDOT and 3D nanofibrous PEDOT transduction interface, that facilitated signal transduction for NADH. 3) A PEDOT hybrid material interface was developed via using a novel bi-functional graphene oxide derivative with high reduction degree and negatively-charged sulphonate terminal functionality (S-RGO) as dopant to create PEDOT:S-RGO which delivered an enhanced electrochemical performance for various analytes.Based on the established CP-based transduction interface, biomolecules (e.g. enzymes) could be coupled to the CP surface to create CP-based bio-interfaces for biosensing. The immobilisation of enzyme was realised via either covalent bonding to a PEDOT derivative bearing a -COOH group (PEDOT-COOH) through EDC/NHS chemistry, or by physical absorption into the 3D porous PEDOT structure. The CP-based bio-interfaces were used to demonstrate the stable immobilisation of two different types of enzymes, i.e. lactate dehydrogenase and lactate oxidase, achieving the biosensing of analytes by relay bioelectrochemical signal transduction.Together, CP was employed as the CP-based device interface for the fabrication of a flexible and wearable biosensing device. A 3D honeycomb-structured graphene network was generated in-situ on a flexible polyimide surface by mask-free patterning using laser irradiation. The substrate was then reinforced with PEDOT as a polymeric binder to stabilise the 3D porous network by adhesion and binding, thus minimising the delamination of the biosensing interface under deformation and enhancing the mechanical behaviours for use in flexible and wearable devices. The subsequent nanoscale-coating of Prussian blue and immobilisation of enzyme into the 3D porous network provided a flexible platform for wearable electrochemical biosensors to detect lactate in sweat.
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| 4. |
- Ross, Georgina M. S., et al.
(författare)
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Interconnectable solid-liquid protein extraction unit and chip-based dilution for multiplexed consumer immunodiagnostics
- 2020
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Ingår i: Analytica Chimica Acta. - : ELSEVIER. - 0003-2670 .- 1873-4324. ; 1140, s. 190-198
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Tidskriftsartikel (refereegranskat)abstract
- While consumer-focused food analysis is upcoming, the need for multiple sample preparation and handling steps is limiting. On-site and consumer-friendly analysis paradoxically still requires laboratory based and skill-intensive sample preparation methods. Here, we present a compact, inexpensive, and novel prototype immunosensor combining sample preparation and on-chip reagent storage for multiplex allergen lateral flow immunosensing. Our comprehensive approach paves the way for personalized consumer diagnostics. The prototype allows for handheld solid-liquid extraction, pipette-free on-chip dilution, and adjustment of sample concentrations into the appropriate assay dynamic working range. The disposable and interconnectable homogenizer unit allows for the extraction and 3D-sieve based filtration of allergenic proteins from solid bakery products in 1 min. The homogenizer interconnects with a 3D-printed unibody lab-on-a-chip (ULOC) microdevice, which is used to deliver precise volumes of sample extract to a reagent reservoir. The reagent reservoir is implemented for on-chip storage of carbon nanoparticle labeled antibodies and running buffer for dilution. The handheld prototype allows for total homogenization of solid samples, solid-liquid protein extraction, 3D-printed sieve based filtration, ULOCenabled dilution, mixing, transport, and smartphone-based detection of hazelnut and peanut allergens in solid bakery products with limited operational complexity. The multiplex lateral flow immunoassay (LFIA) detects allergens as low as 0.1 ppm in real bakery products, and the system is already consumer operable, demonstrating its potential for future citizen science approaches. The designed system is suitable for a wide range of analytical applications outside of food safety, provided an LFIA is available. (C) 2020 Elsevier B.V. All rights reserved.
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| 5. |
- Ross, Georgina M. S., et al.
(författare)
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Unraveling the Hook Effect: A Comprehensive Study of High Antigen Concentration Effects in Sandwich Lateral Flow Immunoassays
- 2020
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Ingår i: Analytical Chemistry. - : AMER CHEMICAL SOC. - 0003-2700 .- 1520-6882. ; 92:23, s. 15587-15595
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Tidskriftsartikel (refereegranskat)abstract
- Sandwich lateral flow immunoassays (LFIAs) are limited at high antigen concentrations by the hook effect, leading to a contradictory decrease in the test line (T) intensity and false-negative results. The hook effect is mainly associated with the loss of T, and research focuses on minimizing this effect. Nevertheless, the control line (C) intensity is also affected at higher analyte concentrations, undesirably influencing the T/C ratio in LFIA readers. The main aim of this work is to identify and understand these high antigen concentration effects in order to develop ubiquitous strategies to interpret and mitigate such effects. Four complementary experiments were performed: performance assessment of three different allergen LFIAs (two for hazelnut, one for peanut) over 0.075-3500 ppm, LFIAs with C only, surface plasmon resonance (SPR) binding experiments on the immobilized control antibody, and smartphone video recording of LFIAs during their development. As antigen concentrations increase, the C signal decreases before the T signal does, suggesting that distinct mechanisms underlie these intensity reductions. Reduced binding at the C occurred even in the absence of T, so the upfront T does not explain the loss of C. SPR confirmed that the C antibody favors binding with free labeled antibody compared with a labeled antibody-analyte complex, indicating that in antigen excess, binding is reduced at C before T. Finally, a smartphone-based video method was developed for dynamically monitoring the LFIA development in real time to distinguish between different concentration-dependent effects. Digitally analyzing the data allows clear differentiation of highly positive samples and false-negative samples and can indicate whether the LFIA is in the dynamic working range or at critically high concentrations. The aim of this work is to identify and understand such high antigen concentration effects in order to develop ubiquitous strategies to interpret and mitigate such effects.
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| 6. |
- Tsagkaris, A. S., et al.
(författare)
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A microfluidic paper-based analytical device (mu PAD) with smartphone readout for chlorpyrifos-oxon screening in human serum
- 2021
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Ingår i: Talanta. - : Elsevier. - 0039-9140 .- 1873-3573. ; 222
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Tidskriftsartikel (refereegranskat)abstract
- Acute intoxication incidents due to neurotoxic organophosphate (OP) insecticides are occasionally reported, related either to suicidal attempts or occupational exposure due to the misuse of protective equipment. Among them, chlorpyrifos is a compound related to great controversy, which is still authorized and easily accessible in many countries around the world. However, to screen for its exposure markers, instrumental methods are commonly applied, which cannot enable rapid monitoring at an early stage of an intoxication. Therefore, in this study, a microfluidic paper-based analytical device (mu PAD) able to rapidly screen for chlorpyrifos-oxon, the toxic chlorpyrifos metabolite, in human serum was developed and fully validated. The mu PAD combines wax-printed butyrylcholinesterase (BChE) paper sensors, a lab-on-a-chip (LOC) prototype injector and a smartphone as the analytical detector. In principle, the wax-printed strips with adsorbed BChE are embedded into LOC injectors able to deliver samples and reagents on-demand. A smartphone reader was used to monitor the color development on the strips providing binary qualitative results. mu PAD method performance characteristics were thoroughly evaluated in terms of specificity, detection capability (CC beta) and ruggedness. The developed analytical platform is rapid (results within 10 min), cost-efficient (0.70 (sic)), potentially applicable at the point-of-need and attained a low CC beta (10 mu g L-1 in human serum). Finally, mu PAD characteristics were critically compared to wellestablished methods, namely an in-house BChE microplate assay and liquid chromatography tandem mass spectrometry.
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| 7. |
- Tyagi, Manav, et al.
(författare)
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Radially actuating conducting polymer microactuators as gates for dynamic microparticle sieve based on printed microfluidics
- 2023
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Ingår i: Sensors and actuators. B, Chemical. - : ELSEVIER SCIENCE SA. - 0925-4005 .- 1873-3077. ; 382
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Tidskriftsartikel (refereegranskat)abstract
- A new radially expanding conducting polymer microactuator is presented. The radially expanding micro-actuators are used as electroactive gates in an electrically controlled microparticle sieve. A novel configuration to dynamically filter particles of different sizes in a microfluidic chip is conceptualized. Micropillars of SU-8 combined with conducting polymers to provide the radial actuation are positioned in a microfluidic chip with a specifically designed 3D printed housing to allow for selective filtration of microparticles with varied sizes. These pillar-shaped microactuators of polypyrrole actuate radially to function as dynamic gates for the fluidic channel, controlling the porosity of the filter allowing for the filtration of specific size of microparticles. This sieve design provides user defined channel width modulation with external stimuli. Photolithography and electrochemical polymerizations are combined with additive manufacturing to fabricate the individual func-tional parts of the microfluidic filter. To demonstrate the new conceptual filter design, we have shown filtration of microparticles of the sizes 60, 80, 90 and 100 mu m by electrically actuating micropillars of the dynamic gate. The flow and aggregation of the microparticles were analysed at the dynamic gates to characterize the perfor-mance of the filter.
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| 8. |
- Xiao, Chi, et al.
(författare)
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Print-and-stick unibody microfluidics coupled surface plasmon resonance (SPR) chip for smartphone imaging SPR (Smart-iSRP)
- 2022
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Ingår i: Analytica Chimica Acta. - : Elsevier. - 0003-2670 .- 1873-4324. ; 1201
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Tidskriftsartikel (refereegranskat)abstract
- The design of a smartphone imaging surface plasmon resonance (Smart-iSPR) system integrated with an affordable 3D-printed microfluidic SPR chip fabricated via a facile manufacturing approach could pave the way towards the development of miniaturized and integrated smartphone iSPR biosensors for emerging point-of-use applications. Conventional smartphone-based SPR systems using soft photolithography for the fabrication of microfluidics SPR chips are costly, labour-intensive and required a specially-equipped light-controlled environment, that is inadequate and mismatched with the consumer-based smartphone detection platform. Herein, we report the design, fabrication and testing of an innovative print-and-stick unibody microfluidics coupled SPR chip for smartphone iSPR. The 3Dprinted microfluidics (~V0.006) is assembled via an aptly-sized adhesive tape with the gold SPR sensing surface. Such a simple integrated microfluidic SPR chip with the print-and-stick configuration has a high resistance to fluid leakages at the channel-to-sensor interface with pressure up to 66.9 Pa and the tubingto-inset interfaces with pressure up to 86.9 Pa. The smartphone iSPR platform weighs 138 g and with a dimension of around 70 x 60 x 40 mm3, and its performance was characterized using a standard Biacore (R) 02-microglobulin calibration kit. The sensorgrams obtained by the smartphone iSPR show all the typical characteristics for surface functionalization, association and dissociation events. The smartphone iSPR responds linearly to 02-microglobulin within the range of 10-200 nM (R2 = 0.986) with a limit-ofdetection (LOD) of 1.5 nM. Given the miniaturized feature and simple camera-based imaging smartphone iSPR, the analytical performance is satisfactory when compared with the analytical dynamic range of 2 -32 nM described in the Biacore (R) protocol.(c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 9. |
- Zhong, Yong, 1987-, et al.
(författare)
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A Versatile Flexible Polymer Actuator System for Pumps, Valves, and Injectors Enabling Fully Disposable Active Microfluidics
- 2021
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Ingår i: Advanced Materials Technologies. - : John Wiley & Sons. - 2365-709X. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- To control and manipulate fluids in lab‐on‐a‐chip (LOC) devices, active components such as pumps, valves, and injectors are necessary. However, such components are often complex and expensive to fabricate, limiting integration in disposable LOCs. A new type of flexible, all‐polymer diaphragm actuator system, called Double Diaphragm Active Polymer Actuator (DDAPA), is presented as a single modular unit that can be repurposed to diverse active microfluidic components. To demonstrate the versatility of the DDAPA concept, the DDAPA devices are investigated in three different configurations: as a single operation microinjector, as a flow regulating element, and as a pump in a hybrid configuration with unibody‐LOC unidirectional systems. The working principle, fabrication process, and the three examples of microfluidic components are presented. The trilayer diaphragm actuator is realized using the conductive polymer poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate as the actuating material and thiol‐acrylate‐based ionogels as solid‐state electrolyte and base material. The three demonstrators show the feasibility of using the DDAPA module to inject liquids, regulate flow, and unidirectionally pump fluids up to 112 µL min−1 when coupled with a 3D printed unibody check valve. Hence, the presented concept with a simple mechanism and easy manufacturability, broadens the choice of disposable actuators compatible with fully disposable autonomous LOC solutions.
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