| 1. |
- 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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| 2. |
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| 3. |
- 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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| 4. |
- 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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| 7. |
- 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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| 8. |
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| 9. |
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| 10. |
- 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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| 11. |
- 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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| 12. |
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| 13. |
- 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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| 14. |
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| 15. |
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| 16. |
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| 17. |
- 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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| 18. |
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| 19. |
- 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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| 20. |
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| 21. |
- Filippini, Daniel, 1968-, et al.
(författare)
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Computer screen photo-assisted techniques
- 2005
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Ingår i: Encyclopedia of Sensors. - California, USA : American Scientific Publishers. - 9781588830562 - 158883056X ; , s. -8000
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The applications of sensors range from medical diagnostics to industrial manufacturing and to defense and national security applications. When an area spans such a large diversity of research, and where research from many different countries is also involved, a review of these developments becomes especially useful. Because it bridges science and technology the field also provides a desired interaction between researchers and research in technologically advanced and developing countries. The present series of volumes, "The Encyclopedia of Sensors" , the first of its kind, is intended to provide a timely compendium of the entire field. As such it can be expected to play a significant role in worldwide future progress and understanding."
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| 22. |
- Filippini, Daniel, 1968-, et al.
(författare)
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Computer screen photo-assisted techniques for global monitoring of environmental and sanitary parameters
- 2007
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 121:1, s. 93-102
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Tidskriftsartikel (refereegranskat)abstract
- The computer screen photo-assisted technique (CSPT) is a measuring method that uses regular computer screens as controlled light sources and web cameras as imaging detectors for optical evaluations of sensing substances, which optical properties respond to target analytes. The fact, that CSPT uses a globally distributed and familiar infrastructure as instrumentation and that is able to serve multiple targets with the same setup, makes it an attractive candidate for home testing. This article reviews the CSPT concept and focuses in two recent studies that demonstrate thorough CSPT determinations using a handy and eventually disposable assay format, with the potential to be as ubiquitous as the CSPT platforms themselves. The implications of such combination of technologies is discussed, and its potential to support the global monitoring of environmental and sanitary parameters, using Internet geography browsers, is analyzed. © 2006 Elsevier B.V. All rights reserved.
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