| 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. |
- Khaldi, Alexandre, 1982-, et al.
(författare)
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Patterning highly conducting conjugated polymer electrodes for soft and flexible microelectrochemical devices
- 2018
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 10:17, s. 14978-14985
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for soft actuators in various biomedical applications in order to manipulate delicate objects such as cells and tissues. Soft actuators are able to adapt to any shape and limit the stress applied to delicate objects. Conjugated polymer actuators, especially in the so-called trilayer configuration, are interesting candidates for driving such micromanipulators. However, challenges involved in patterning the electrodes in a trilayer with individual contact have prevented further development of soft micromanipulators based on conjugated polymer actuators. To allow such patterning, two printing-based patterning techniques have been developed. First an oxidant layer is printed using either syringe-based printing or micro-contact printing, followed by vapor phase polymerization of the conjugated polymer. Sub-millimeter patterns with electronic conductivities of 800 Scm-1 are obtained. Next, laser ablation is used to cleanly cut the final device structures including the printed patterns, resulting in fingers with individually controllable digits and miniaturized hands. The methods presented in this paper will enable integration of patterned electrically active conjugated polymer layers in many types of complex 3-D structures.
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| 3. |
- Abata, E., et al.
(författare)
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Study of energy response and resolution of the ATLAS barrel calorimeter to hadrons of energies from 20 to 350 GeV
- 2010
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576 .- 0167-5087. ; 621:1-3, s. 134-150
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Tidskriftsartikel (refereegranskat)abstract
- A fully instrumented slice of the ATLAS detector was exposed to test beams from the SPS (Super Proton Synchrotron) at CERN in 2004. In this paper, the results of the measurements of the response of the barrel calorimeter to hadrons with energies in the range 20-350 GeV and beam impact points and angles corresponding to pseudo-rapidity values in the range 0.2-0.65 are reported. The results are compared to the predictions of a simulation program using the Geant 4 toolkit. (C) 2010 Published by Elsevier B.V.
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| 4. |
- Ali Malik, Muhammad, et al.
(författare)
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Imaging fingerprinting of excitation emission matrices
- 2009
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 635:2, s. 196-201
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Tidskriftsartikel (refereegranskat)abstract
- The spectral fingerprinting of the excitation emission matrix (EEM) of fluorescent substances is demonstrated using polychromatic light sources and tri-chromatic image detectors. A model of the measured fingerprints explaining their features and classification performance, based on the polychromatic excitation of the indicators is proposed.Substantial amount of spectral information is retained in the fingerprints as corroborated by multivariate analysis and experimental conditions that favor such situation are identified.In average, for five different substances, the model shows a fitting goodness measured by the Pearsons r coefficient and the root mean square deviation of 0.8541 and 0.0247 respectively, while principal component classification patterns satisfactorily compare with the EEM spectroscopy classification and respectively explain 96% and 93% of the information in the fist two principal components.The measurements can be performed using regular computer screens as illumination and web cameras as detectors, which constitute ubiquitous and affordable platforms compatible with distributed evaluations, in contrast to regular instrumentation for EEM measurements.
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| 5. |
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| 6. |
- Alimelli, Adriano, et al.
(författare)
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Fish freshness detection by a computer screen photoassisted based gas sensor array
- 2007
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 582:2, s. 320-328
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Tidskriftsartikel (refereegranskat)abstract
- In the last years a large number of different measurement methodologies were applied to measure the freshness of fishes. Among them the connection between freshness and headspace composition has been considered by gas chromatographic analysis and from the last two decades by a number of sensors and biosensors aimed at measuring some characteristic indicators (usually amines). More recently also the so-called artificial olfaction systems gathering together many non-specific sensors have shown a certain capability to transduce the global composition of the fish headspace capturing the differences between fresh and spoiled products. One of the main objectives related to the introduction of sensor systems with respect to the analytical methods is the claimed possibility to distribute the freshness control since sensors are expected to be "portable" and "simple". In spite of these objectives, until now sensor systems did not result in any tool that may be broadly distributed. In this paper, we present a chemical sensor array where the optical features of layers of chemicals, sensitive to volatile compounds typical of spoilage processes in fish, are interrogated by a very simple platform based on a computer screen and a web cam. An array of metalloporphyrins is here used to classify fillets of thawed fishes according to their storage days and to monitor the spoilage in filleted anchovies for a time of 8 h. Results indicate a complete identification of the storage days of thawed fillets and a determination of the storage time of anchovies held at room temperature with a root mean square error of validation of about 30 min. The optical system produces a sort of spectral fingerprint containing information about both the absorbance and the emission of the sensitive layer. The system here illustrated, based on computer peripherals, can be easily scaled to any device endowed with a programmable screen and a camera such as cellular phones offering for the first time the possibility to fulfil the sensor expectation of diffused and efficient analytical capabilities. © 2006 Elsevier B.V. All rights reserved.
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| 7. |
- Anderson, Tony, 1973-, et al.
(författare)
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Frog melanophores cultured on fluorescent microbeads : Biomimic-based biosensing
- 2005
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Ingår i: Biosensors & bioelectronics. - : Elsevier BV. - 0956-5663 .- 1873-4235. ; 21:1, s. 111-120
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Tidskriftsartikel (refereegranskat)abstract
- Melanophores are pigmented cells in lower vertebrates capable of quick color changes and thereby suitable as whole cell biosensors. In the frog dermis skin layer, the large and dark pigmented melanophore surrounds a core of other pigmented cells. Upon hormonal stimulation the black-brown pigment organelles will redistribute within the melanophore, and thereby cover or uncover the core, making complex color changes possible in the dermis. Previously, melanophores have only been cultured on flat surfaces. Here we mimic the three dimensional biological geometry in the frog dermis by culturing melanophores on fluorescent plastic microbeads. To demonstrate biosensing we use the hormones melatonin and α-melanocyte stimulating hormone (α-MSH) as lightening or darkening stimuli, respectively. Cellular responses were successfully demonstrated on single cell level by fluorescence microscopy, and in cell suspension by a fluorescence microplate reader and a previously demonstrated computer screen photo-assisted technique. The demonstrated principle is the first step towards "single well/multiple read-out" biosensor arrays based on suspensions of different selective-responding melanophores, each cultured on microbeads with distinctive spectral characteristics. By applying small amount of a clinical sample, or a candidate substance in early drug screening, to a single well containing combinations of melanophores on beads, multiple parameter read-outs will be possible. © 2004 Elsevier B.V. All rights reserved.
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| 8. |
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| 9. |
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| 10. |
- Arwin, Hans, 1950-, et al.
(författare)
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Computer screen photo-assisted measurement of intensity or polarization change of light upon interaction with a sample
- 2006
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Patent (populärvet., debatt m.m.)abstract
- A method for measuring a property of a test sample utilizing one of the test methods ellipsometry, surface plasmon resonance and nephelometry, wherein the method includes the steps; providing a test sample being an object with which an optical interaction with light takes place, illuminating said test sample using a program controlled display as a light source, which program controlled display is composed of at least one activated pixel providing an illumination from an illuminating area of said program controlled display, arranging said program controlled display to illuminate said test sample with polarized light, detecting light emerging from said test sample utilizing a detector coupled to said program and evaluating said property from signals from said detector.
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| 11. |
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| 12. |
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| 13. |
- Bakker, Jimmy W.P., et al.
(författare)
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Computer screen photo-assisted off-null ellipsometry
- 2006
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Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 45:30, s. 7795-7799
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Tidskriftsartikel (refereegranskat)abstract
- The ellipsometric measurement of thickness is demonstrated using a computer screen as a light source and a webcam as a detector, adding imaging off-null ellipsometry to the range of available computer screen photoassisted techniques. The results show good qualitative agreement with a simplified theoretical model and a thickness resolution in the nanometer range is achieved. The presented model can be used to optimize the setup for sensitivity. Since the computer screen serves as a homogeneous large area illumination source, which can be tuned to different intensities for different parts of the sample, a large sensitivity range can be obtained without sacrificing thickness resolution.
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| 14. |
- Bakker, Jimmy W. P., et al.
(författare)
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Enhancing classification capabilities of computer screen photo-assisted fluorescence fingerprinting
- 2005
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Ingår i: Sensors and Actuators B: Chemical. - : Elsevier BV. - 0925-4005. ; 110:2, s. 190-194
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Tidskriftsartikel (refereegranskat)abstract
- The separation of emission from transmitted light for the fingerprinting of fluorescent substances using a computer screen photo-assisted technique (CSPT) is demonstrated. CSPT is a technique for optical evaluation using a simple cell with just a standard computer set and a web camera as instrumentation. It has been demonstrated to be a versatile system for colorimetric and fluorescent fingerprinting. Here the omnidirectional property of fluorescent emission is utilized to separate it from the background, using a simple optical arrangement compatible with CSPT purposes. This enhances the classification capabilities and makes classification at sub-μM concentrations possible.
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| 15. |
- Bakker, Jimmy W.P., et al.
(författare)
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Immunodetection using computer screen photo-assisted ellipsometry
- 2008
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Ingår i: Physica Status Solidi. C: Current Topics in Solid State Physics. - Weinheim, Germany : Wiley-VCH Verlagsgesellschaft. - 1862-6351. ; 5:5, s. 1431-1433
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Tidskriftsartikel (refereegranskat)abstract
- Detection of antibody-antigen reactions is demonstrated by measuring changes in reflectance of light polarized parallel to the plane of incidence, using a computer screen as light source and a web camera as detector, giving results similar to traditional off-null ellipsometry and in accordance with a simplified theoretical model.
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| 16. |
- Bakker, Jimmy W.P., et al.
(författare)
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Two-dimensional micro array fluorescence fingerprinting with a computer screen photo-assisted technique
- 2005
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Ingår i: Spectral Imaging. - : SPIE. ; , s. 9-15
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Detection and classification of fluorescent dyes are demonstrated using a computer screen photo-assisted technique (CSPT). This technique has previously been demonstrated for analyzing fluorescence from 96 wells microtiterplates (200 µl per well) and from a single cuvette with some optics to enhance sensitivity. In this work a custom designed array of wells with a volume of approximately 1 mu;l is used. In order to measure such small volumes without saturating the detector, the transmitted light is masked by placing the sample between two crossed polarizers. This arrangement blocks nearly all the transmitted light, while the emitted light, which is nearly unpolarized, can still be detected. The lowest amount (concentration x volume) of analyte detectable in this setup is about 40 times smaller than in the previous setups.
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| 17. |
- Barkå, Jonas, et al.
(författare)
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Background compensation in computer screen photo-assisted reflectance fingerprinting
- 2006
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 120:1, s. 79-85
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Tidskriftsartikel (refereegranskat)abstract
- The computer screen photo-assisted technique (CSPT) is a method for the classification of colorimetric assays utilizing ordinary computer sets and web cameras as instrumentation. In CSPT measurements the web camera captures the image of the assay under the screen illumination, and typically a spurious spatial distribution of intensities is overlapped on the image. This issue is examined here, focusing on the effect of the sample and illuminating colors on the spatial modulation of intensity. A method for the selection of colors composing an illuminating sequence that minimizes the spatial variability is proposed. The approach is tested for the classification of different color substances showing improvements up to 53% of the intra/inter cluster distance ratio measured in a PCA space, when compared to randomly chosen colors. © 2006 Elsevier B.V. All rights reserved.
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| 18. |
- Bjorklund, Robert, et al.
(författare)
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Automatic optimization of experimental conditions for fast evaluation of diagnostic tests using ubiquitous instrumentation
- 2008
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 134:1, s. 199-205
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Tidskriftsartikel (refereegranskat)abstract
- Rapid quantitative determinations of creatinine, potassium and glucose, all important parameters in routine medical diagnostics, are demonstrated using a computer screen photo-assisted technique (CSPT). CSPT uses regular computer screens as light sources and web cameras as imaging detectors for supporting optical evaluations of diverse character. The ubiquity and versatility of the setup, makes CSPT an attractive candidate for point of care determinations. A robust procedure for the automatic selection of experimental conditions in CSPT evaluation, including camera channels and illuminating colors that minimize the measuring time up to 5 times is described. The method utilizes the correlation between experimental conditions and classification scores, obtained under a generic 50 color training session, to extract measuring sequences as short as 9 s. The extracted measuring conditions automatically adapted to the different tests provided a general, practical and fast approach for CSPT optimization in real scenarios. © 2008 Elsevier B.V. All rights reserved.
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| 19. |
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| 20. |
- Chio, Iok In Christine, et al.
(författare)
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NRF2 Promotes Tumor Maintenance by Modulating mRNA Translation in Pancreatic Cancer
- 2016
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 166:4, s. 936-976
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Tidskriftsartikel (refereegranskat)abstract
- Pancreatic cancer is a deadly malignancy that lacks effective therapeutics. We previously reported that oncogenic Kras induced the redox master regulator Nfe2l2/Nrf2 to stimulate pancreatic and lung cancer initiation. Here, we show that NRF2 is necessary to maintain pancreatic cancer proliferation by regulating mRNA translation. Specifically, loss of NRF2 led to defects in autocrine epidermal growth factor receptor (EGFR) signaling and oxidation of specific translational regulatory proteins, resulting in impaired cap-dependent and cap-independent mRNA translation in pancreatic cancer cells. Combined targeting of the EGFR effector AKT and the glutathione antioxidant pathway mimicked Nrf2 ablation to potently inhibit pancreatic cancer ex vivo and in vivo, representing a promising synthetic lethal strategy for treating the disease.
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| 21. |
- 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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| 22. |
- Comina, German, et al.
(författare)
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3D printed disposable optics and lab-on-a-chip devices for chemical sensing with cell phones
- 2017
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Ingår i: MICROFLUIDICS, BIOMEMS, AND MEDICAL MICROSYSTEMS XV. - : SPIE-INT SOC OPTICAL ENGINEERING. - 9781510605633 - 9781510605640
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Konferensbidrag (refereegranskat)abstract
- Digital manufacturing (DM) offers fast prototyping capabilities and great versatility to configure countless architectures at affordable development costs. Autonomous lab-on-a-chip (LOC) devices, conceived as only disposable accessory to interface chemical sensing to cell phones, require specific features that can be achieved using DM techniques. Here we describe stereo-lithography 3D printing (SLA) of optical components and unibody-LOC (ULOC) devices using consumer grade printers. ULOC devices integrate actuation in the form of check-valves and finger pumps, as well as the calibration range required for quantitative detection. Coupling to phone camera readout depends on the detection approach, and includes different types of optical components. Optical surfaces can be locally configured with a simple polishing-free post-processing step, and the representative costs are 0.5 US$/device, same as ULOC devices, both involving fabrication times of about 20 min.
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| 23. |
- Comina, German, et al.
(författare)
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3D Printed Unibody Lab-on-a-Chip: Features Survey and Check-Valves Integration dagger
- 2015
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Ingår i: Micromachines. - : MDPI. - 2072-666X. ; 6:4, s. 437-451
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Tidskriftsartikel (refereegranskat)abstract
- The unibody lab-on-a-chip (ULOC) concept entails a fast and affordable micro-prototyping system built around a single monolithic 3D printed element (unibody). A consumer-grade stereo lithography (SL) 3D printer can configure ULOCs with different forms of sample delivery, transport, handling and readout, while minimizing material costs and fabrication time. ULOC centralizes all complex fabrication procedures and replaces the need for clean room resources, delivering prototypes for less than 1 US$, which can be printed in 10 min and ready for testing in less than 30 min. Recent examples of ULOC integration of transport, chemical sensing for optical readout and flow mixing capabilities are discussed, as well as the integration of the first check-valves for ULOC devices. ULOC valves are strictly unidirectional up to 100 psi, show an exponential forward flow behavior up to 70 psi and can be entirely fabricated with the ULOC approach.
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| 24. |
- Comina, German, et al.
(författare)
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A 3D printed device for quantitative enzymatic detection using cell phones
- 2016
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Ingår i: Analytical Methods. - : Royal Society of Chemistry. - 1759-9660 .- 1759-9679. ; 8:32, s. 6135-6142
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Tidskriftsartikel (refereegranskat)abstract
- A disposable device for quantitative enzymatic detection capable of coupling illumination and image readouts from cell phones is demonstrated. The device integrates a calibration range for glutamate detection, utilizes the phone screen as a light source, and provides the necessary actuation for autonomous operation. Custom made optics required to couple to the cell phone camera is accomplished using affordable stereolithography (SLA) 3D printers. The described method does not involve polishing, requires only two steps from design to implementation, and can be locally applied to 3D printed lab-on-a-chip (LOC) prototypes, using the same materials. Optical finishing and dimensional variability within 2% were achieved, supporting entirely arbitrary geometries for elements larger than 400 mm in radius. Representative fabrication times and costs were 20 min and $0.50 USD per prototype.
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| 25. |
- Comina, German, et al.
(författare)
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Autonomous Chemical Sensing Interface for Universal Cell Phone Readout
- 2015
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 54:30, s. 8708-8712
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Tidskriftsartikel (refereegranskat)abstract
- Exploiting the ubiquity of cell phones for quantitative chemical sensing imposes strong demands on interfacing devices. They should be autonomous, disposable, and integrate all necessary calibration and actuation elements. In addition, a single design should couple universally to a variety of cell phones, and operate in their default configuration. Here, we demonstrate such a concept and its implementation as a quantitative glucose meter that integrates finger pumps, unidirectional valves, calibration references, and focusing optics on a disposable device configured for universal video acquisition.
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| 26. |
- Comina, German, et al.
(författare)
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Low cost lab-on-a-chip prototyping with a consumer grade 3D printer
- 2014
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 14:16, s. 2978-2982
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Tidskriftsartikel (refereegranskat)abstract
- Versatile prototyping of 3D printed lab-on-a-chip devices, supporting different forms of sample delivery, transport, functionalization and readout, is demonstrated with a consumer grade printer, which centralizes all critical fabrication tasks. Devices cost 0.57US$ and are demonstrated in chemical sensing and micromixing examples, which exploit established principles from reference technologies.
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| 27. |
- Comina, German, et al.
(författare)
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PDMS lab-on-a-chip fabrication using 3D printed templates
- 2014
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 14:2, s. 424-430
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Tidskriftsartikel (refereegranskat)abstract
- The fabrication of conventional PDMS on glass lab-on-a-chip (LOC) devices, using templates printed with a commercial (2299 US$) micro-stereo lithography 3D printer, is demonstrated. Printed templates replace clean room and photolithographic fabrication resources and deliver resolutions of 50 mu m, and up to 10 mu m in localized hindrances, whereas the templates are smooth enough to allow direct transfer and proper sealing to glass substrates. 3D printed templates accommodate multiple thicknesses, from 50 mu m up to several mm within the same template, with no additional processing cost or effort. This capability is exploited to integrate silicone tubing easily, to improve micromixer performance and to produce multilevel fluidics with simple access to independent functional surfaces, which is illustrated by time-resolved glucose detection. The templates are reusable, can be fabricated in under 20 min, with an average cost of 0.48 US$, which promotes broader access to established LOC configurations with minimal fabrication requirements, relieves LOC fabrication from design skills and provides a versatile LOC development platform.
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| 28. |
- Comina, German, et al.
(författare)
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Towards autonomous lab-on-a-chip devices for cell phone biosensing
- 2016
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 77, s. 1153-1167
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Tidskriftsartikel (refereegranskat)abstract
- Modern cell phones are a ubiquitous resource with a residual capacity to accommodate chemical sensing and biosensing capabilities. From the different approaches explored to capitalize on such resource, the use of autonomous disposable lab-on-a-chip (LOC) devices conceived as only accessories to complement cell phones underscores the possibility to entirely retain cell phones ubiquity for distributed biosensing. The technology and principles exploited for autonomous LOC devices are here selected and reviewed focusing on their potential to serve cell phone readout configurations. Together with this requirement, the central aspects of cell phones resources that determine their potential for analytical detection are examined. The conversion of these LOC concepts into universal architectures that are readable on unaccessorized phones is discussed within this context. (C) 2015 Elsevier B.V. All rights reserved.
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| 29. |
- Di, Natale C., et al.
(författare)
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An experimental biomimetic platform for artificial olfaction
- 2008
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:9
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Tidskriftsartikel (refereegranskat)abstract
- Artificial olfactory systems have been studied for the last two decades mainly from the point of view of the features of olfactory neuron receptor fields. Other fundamental olfaction properties have only been episodically considered in artificial systems. As a result, current artificial olfactory systems are mostly intended as instruments and are of poor benefit for biologists who may need tools to model and test olfactory models. Herewith, we show how a simple experimental approach can be used to account for several phenomena observed in olfaction. An artificial epithelium is formed as a disordered distributed layer of broadly selective color indicators dispersed in a transparent polymer layer. The whole epithelium is probed with colored light, imaged with a digital camera and the olfactory response upon exposure to an odor is the change of the multispectral image. The pixels are treated as olfactory receptor neurons, whose optical properties are used to build a convergence classifier into a number of mathematically defined artificial glomeruli. A non-homogenous exposure of the test structure to the odours gives rise to a time and spatial dependence of the response of the different glomeruli strikingly similar to patterns observed in the olfactory bulb. The model seems to mimick both the formation of glomeruli, the zonal nature of olfactory epithelium, and the spatio-temporal signal patterns at the glomeruli level. This platform is able to provide a readily available test vehicle for chemists developing optical indicators for chemical sensing purposes and for biologists to test models of olfactory system organization. © 2008 Di Natale et al.
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| 30. |
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| 31. |
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| 32. |
- Di Natale, C, et al.
(författare)
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An artificial olfaction system based on the optical imaging of a large array of chemical reporters
- 2009
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Ingår i: SENSORS AND ACTUATORS B-CHEMICAL. - : Elsevier BV. - 0925-4005. ; 142:2, s. 412-417
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Tidskriftsartikel (refereegranskat)abstract
- Electronic noses are object of research since more than two decades; nonetheless. the analogies between natural and olfaction systems are still limited to the selectivity properties of the receptors. The implementation of more sophisticated features such as the large number of receptors and the glomeruli layer have been hampered by technical difficulties related to the management of a large number of contemporaneous signals. As demonstrated in the past, optical imaging is a read-out technique for sensors development that can provide large sensor arrays. In this paper an artificial olfaction system based on the imaging of a continuous layer of chemical indicators is illustrated. The system incorporates an array of thousands of sensors, corresponding to the pixels of the image. The choice of Computer Screen Photoassisted Technology as a platform for optical interrogation of the sensing layer allows for the definition of a strategy for an automatic definition of a glomeruli layer based on the classification of the optical fingerprints of the image pixels. Chemical indicators were dissolved into a polymeric matrix providing the further property of odor diffusion mimicking the functions of the olfactory mucosa. The system has been tested in a simple experiment and data have been treated applying a lateral inhibition to the glomeruli layer resulting in a dynamic pattern resembling that observed in natural olfaction.
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| 33. |
- Di Natale, Corrado, et al.
(författare)
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Evaluation of the performance of sensors based on optical imaging of a chemically sensitive layer
- 2010
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Ingår i: ANALYTICAL AND BIOANALYTICAL CHEMISTRY. - : Springer Science Business Media. - 1618-2642 .- 1618-2650. ; 397:2, s. 613-621
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Tidskriftsartikel (refereegranskat)abstract
- Interest in the use of the optical properties of chemical indicators is growing steadily. Among the optical methods that can be used to capture changes in sensing layers, those producing images of large-area devices are particularly interesting for chemical sensor array development. Until now, few studies addressed the characterization of image sensors from the point of view of their chemical sensor application. In this paper, a method to evaluate such performance is proposed. It is based on the simultaneous measurement of absorption events in a metalloporphyrin layer with an image sensor and a quartz microbalance (QMB). Exploiting the well-known behaviour of QMB, comparison of signals enables estimation of the minimum amount of absorbed molecules that the image sensor can detect. Results indicate that at the single pixel level a standard image sensor (for example a webcam) can easily detect femtomoles of absorbed molecules. It should therefore be possible to design sensor arrays in which the pixels of images of large-area sensing layers are regarded as individual chemical sensors providing a ready and simple method for large sensor array development.
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| 34. |
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| 35. |
- Dini, Francesca, et al.
(författare)
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Chemical sensitivity of self-assembled porphyrin nano-aggregates
- 2009
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Ingår i: NANOTECHNOLOGY. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 20:5, s. 055502-
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Tidskriftsartikel (refereegranskat)abstract
- Nanostructured molecular assemblies may provide additional sensing properties not found in other arrangements of the same basic constituents. Among three-dimensional structures, nanotubes are particularly appealing for applications as chemical sensors, because of the potential inclusion of different guests inside the cavity or the induced modification of the skeletal interaction after analyte binding. Porphyrins are a class of compounds characterized by brilliant sensing properties, appearing also in non-ordered solid-state aggregates. In recent years, it was reported that aggregation of oppositely charged porphyrins led to the formation of self-assembled nanotubes and in this paper their sensing properties, both in solution and in the solid state, have been investigated. The interactions of porphyrin nanotubes with guest molecules have been monitored by following the changes in their UV-vis spectra. The results obtained have been exploited to build up a sensing platform based on a computer screen as a light source and a digital camera as detector. Porphyrin nanostructures exhibited an enhanced sensitivity to different compounds with respect to those shown by single porphyrin subunits. The reason for the increased sensitivity may be likely found in an additional sensing mechanism related to the modulation of the strength of the forces that keep the supramolecular ensemble together.
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| 36. |
- Dini, Francesca, et al.
(författare)
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Computer screen assisted digital photography
- 2013
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 179:SI, s. 46-53
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Tidskriftsartikel (refereegranskat)abstract
- The computer screen photo-assisted techniques (CSPT) have been developed during the last 10 years through an extensive collaboration between University of Rome "Tor Vergata" and Linkoping University in Sweden. CSPT has thus evolved into a concept we now call computer screen assisted digital photography, yielding detailed information about the interaction between color indicators and (volatile) analytes. In the present paper, we give a brief summary of the CSPT concept and its connection to digital photography. We concentrate, however, on the most recent results, which were obtained by using most of the degrees of freedom offered by a computer screen as a light source and a digital (web) camera as a detector. Thus, we describe in detail recent experiments on cotton yarns impregnated with color indicators for volatile organic molecules. The interaction between the color indicators and molecules, like trimethylamine, was investigated by CSPT in high dynamic imaging together with a background noise limiting algorithm. It is shown that the simultaneous use of the last two additions to the CSPT concept considerably enhances the chemical sensing ability of CSPT. It is concluded that the collaboration between Rome and Linkoping has generated a useful platform for further developments of chemical analysis with a ubiquitous instrumentation, a (computer) screen and a web camera. This technique is aimed at facilitating the assembly of opto-chemical sensors with evident benefits in the reduction of cost of sensor systems and in an increased integrability with the existent telecommunication infrastructures.
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| 37. |
- Dini, Francesca, et al.
(författare)
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Data processing for image-based chemical sensors: unsupervised region of interest selection and background noise compensation
- 2012
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Verlag (Germany). - 1618-2642 .- 1618-2650. ; 402:2, s. 823-832
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Tidskriftsartikel (refereegranskat)abstract
- Natural olfaction suggests that numerous replicas of small sensors can achieve large sensitivity. This concept of sensor redundancy can be exploited by use of optical chemical sensors whose use of image sensors enables the simultaneous measurement of several spatially distributed indicators. Digital image sensors split the framed scene into hundreds of thousands of pixels each corresponding to a portion of the sensing layer. The signal from each pixel can be regarded as an independent sensor, which leads to a highly redundant sensor array. Such redundancy can eventually be exploited to increase the signal-to-noise ratio. In this paper we report an algorithm for reduction of the noise of pixel signals. For this purpose, the algorithm processes the output of groups of pixels whose signals share the same time behavior, as is the case for signals related to the same indicator. To define these groups of pixels, unsupervised clustering, based on classification of the indicator colors, is proposed here. This approach to signal processing is tested in experiments on the chemical sensitivity of replicas of eight indicators spotted on to a plastic substrate. Results show that the groups of pixels can be defined independently of the geometrical arrangement of the sensing spots, and substantial improvement of the signal-to-noise ratio is obtained, enabling the detection of volatile compounds at any location on the distributed sensing layer.
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| 38. |
- Dini, Francesca, et al.
(författare)
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Polymer matrices effects on the sensitivity and the selectivity of optical chemical sensors
- 2011
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Ingår i: SENSORS AND ACTUATORS B-CHEMICAL. - : Elsevier Science B.V., Amsterdam.. - 0925-4005. ; 154:2, s. 220-225
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Tidskriftsartikel (refereegranskat)abstract
- Polymers are commonly used in optical chemical sensors as inert supports for indicator dyes keeping the molecules apart to allow for exposure to analytes and to maintain the peculiar optical properties of the sensitive dyes. However, the partitioning properties of polymers may play a significant role in determining the sensitivity of the sensors. Herewith, the properties of a single dye blended with different polymers have been studied through optical absorbance changes elicited by the exposure to organic vapors. Results show that the partitioning properties of polymers modulate the response of the dye and confer a combinatorial selectivity to the system, allowing for the recognition of vapors.
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| 39. |
- Dini, Francesca, et al.
(författare)
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Polymers with embedded chemical indicators as an artificial olfactory mucosa
- 2010
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Ingår i: ANALYST. - : Royal Society of Chemistry. - 0003-2654. ; 135:6, s. 1245-1252
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Tidskriftsartikel (refereegranskat)abstract
- Physiological investigations suggest that the olfactory mucosa probably plays an ancillary role in the recognition of odours introducing a sort of chromatographic separation that, together with the zonal distribution of olfactory receptors, gives place to selective spatio-temporal response patterns. It has been recently suggested that this behaviour may be simulated by chemical sensors embedded in continuous polymer layers. In this paper, in analogy to the biology of olfaction, a simple and compact platform able to separate and detect gases and vapours on the basis of their diffusion properties is proposed. In such a system, broadly selective colour indicators, such as metalloporphyrins, are embedded in continuous layers of polymers with different sorption properties. The exposure to various alcohols and amines shows that the porphyrins are mainly responsible for the recognition of the molecular family, while the occurring spatio-temporal signal patterns make possible the identification of the individual chemical species.
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| 40. |
- Eriksson, E., et al.
(författare)
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Geometric Flow Control Lateral Flow Immunoassay Devices (GFC-LFIDs): A New Dimension to Enhance Analytical Performance
- 2019
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Ingår i: Research (Washington, D.C.). - : American Association for the Advancement of Science. - 2639-5274.
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Tidskriftsartikel (refereegranskat)abstract
- The nitrocellulose (NC) membrane based lateral flow immunoassay device (LFID) is one of the most important and widely used biosensor platforms for point-of-care (PoC) diagnostics. However, the analytical performance of LFID has limitations and its optimization is restricted to the bioassay chemistry, the membrane porosity, and the choice of biolabel system. These bottom neck technical issues resulted from the fact that the conventional LFID design principle has not evolved for many years, which limited the LFID for advanced biosensor applications. Here we introduce a new dimension for LFID design and optimization based on geometric flow control (GFC) of NC membranes, leading to highly sensitive GFC-LFID. This novel approach enables comprehensive flow control via different membrane geometric features such as the width (w) and the length (l) of a constriction, as well as its input angle (?1) and output angle (?2). The GFC-LFID (w=0.5 mm, l=7 mm, ?1= 60, ?2= 45) attained a 10-fold increase in sensitivity for detection of interleukin-6 (IL-6), compared with conventional LFID, whereas reducing by 10-fold the antibody consumption. The GFC-LFID detects IL-6 over a linear range of 0.1-10?ng/mL with a limit of detection (LoD) of 29?pg/mL, which even outperforms some commercial IL-6 LFIDs. Such significant improvement is attained by pure geometric control of the NC membrane, without additives, that only relaying on a simple high throughput laser ablation procedure suitable for integration on regular large-scale manufacturing of GFC-LFIDs. Our new development on GFC-LFID with the combination of facile scalable fabrication process, tailored flow control, improved analytical performance, and reduced antibodies consumption is likely to have a significant impact on new design concept for the LFID industry.
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| 41. |
- Fallqvist, Amie, et al.
(författare)
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Optically addressable field effect nano-environments for chemical imaging
- 2009
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Ingår i: Procedia Chemistry. - : ELSEVIER SCIENCE BV. - 1876-6196. ; 1:1, s. 224-227
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Tidskriftsartikel (refereegranskat)abstract
- An optically addressable field effect device Incorporating functionalized nano-environments is demonstrated for the generation of multiple response signatures of a same analyte-sensing material combination. The device can operate unsupervised and different response mechanism can be simultaneously tested and incorporated in a multidimensional response. This proof of concept explores the well-known Pd-H-2 case, while the concept is a breadboard for chemical imaging experiments.
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| 42. |
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| 43. |
- Filippini, Daniel, et al.
(författare)
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Adaptive illumination in computer screen assisted spectral fingerprinting
- 2005
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 86:8, s. 084101-
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Tidskriftsartikel (refereegranskat)abstract
- The computer screen photoassisted technique (CSPT) uses displays as controlled light sources for measuring spectral fingerprints of color substances, such as those present in bioassays. Here, the possibility of tuning the illuminating sequences for matching CSPT fingerprints with target spectral transmittances is demonstrated. This approach enables robust classification, orders of magnitude form mismatches, and establish a systematic method for adapting optimum illuminating sequences to any unknown measuring platform. © 2005 American Institute of Physics.
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| 44. |
- Filippini, Daniel, et al.
(författare)
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Chemical image generation with a grid-gate device
- 2004
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 96:12, s. 7583-7590
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Tidskriftsartikel (refereegranskat)abstract
- Scanning light pulse technique generating distinctive chemical images of diverse gases is demonstrated using a sensing arrangement that allows unrestricted choice of sensing materials, disregarding its conductivity or morphology. The present device, a metal oxide semiconductor structure, disentangles biasing from chemical functions by providing an inert grid as a gate that supplies the proper biasing, while functional materials even in the form of disconnected clusters can be used for sensing. The reading of conductimetric chemical responses of clustered materials, in nominal operating conditions, is demonstrated by the generation of chemical images acquired for inversion biasing conditions. © 2004 American Institute of Physics.
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| 45. |
- Filippini, Daniel, et al.
(författare)
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Chemical images generated by large area homogeneous illumination of metal-insulator-semiconductor structures
- 2003
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 82:21, s. 3791-3793
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Tidskriftsartikel (refereegranskat)abstract
- The induction of distinctive chemical images in the field-effect devices upon gas exposure by the use of a controlled large area illumination provided by a computer screen was reported. To generate two-dimensional photocurrent images, the concurrent optical and chemical modulation of the semiconductor surface potential of a single metal-oxide-semiconductor capacitor was used. It was concluded that the use of a computer screen as a programmable light source simplifies a normally complex setup.
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| 46. |
- Filippini, Daniel, et al.
(författare)
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Chemical imaging by a computer screen aided scanning light pulse technique
- 2002
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 81:20, s. 3891-3893
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Tidskriftsartikel (refereegranskat)abstract
- The demonstration of a scanning light pulse technique (SLPT) for the generation of selective chemical images was done. The programmable light source provided by a standard cathode-rays tube computer screen was used for this purpose. The testing of the concept was done with a metal-oxide-semiconductor capacitor with catalytic gates of platinum and palladium spatially distributed in transversal directions.
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| 47. |
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| 48. |
- Filippini, Daniel, 1968-, et al.
(författare)
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Chemical Sensing with Familiar Devices
- 2006
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Ingår i: Angewandte Chemie : : a journal of the Gesellschaft Deutscher Chemiker.. International edition. - : Wiley. ; 45:23, s. 3800-3803
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Tidskriftsartikel (refereegranskat)
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| 49. |
- Filippini, Daniel, et al.
(författare)
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Computer screen photo-assisted reflectance fingerprinting
- 2005
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 107:2, s. 580-586
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Tidskriftsartikel (refereegranskat)abstract
- The characterization of opaque color samples using reflected light is demonstrated with a computer screen photo-assisted technique (CSPT). CSPT utilizes standard computer screens as light sources and conventional web cameras as detectors to perform colorimetric or fluorescent evaluations that retain key spectral features of the tested substances. In this work, the fingerprinting of samples spectral reflectances is achieved by evaluating the reflected light under controlled computer screen illumination. Two different methods for processing of features are investigated, revealing complementary properties for classifications purposes. The attainable classification enables to distinguish different colors from just hues of a same color. © 2004 Elsevier B.V. All rights reserved.
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| 50. |
- Filippini, Daniel, et al.
(författare)
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Computer screen photo-assisted spectral fingerprinting of luminescent polythiophene pH reporter
- 2004
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Ingår i: IEEE Sensors. Proceedings. - : IEEE. - 1930-0395 .- 2168-9229. ; 3, s. 1377-1380
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Tidskriftsartikel (refereegranskat)abstract
- The capability of the computer screen photo-assisted technique (CSPT)for the spectral fingerprinting of a photoactive polythiophene derivative (POWT) used as pH reporter is demonstrated. POWT is part of a family of industrial scalable materials, well established for organic electronics and biomedical applications, which is used here to demonstrate the capability of CSPT for tracing key spectral features. The ability of CSPTfor substance classification, corroborated by principal component analysis (PCA), successfully compares to standard spectroscopy, especially considering the involved equipments: CSPT is only a computer set and a web camera.
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