| 1. |
- Abata, E., et al.
(författare)
-
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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| 2. |
- Comina, German, et al.
(författare)
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Low cost lab-on-a-chip prototyping with a consumer grade 3D printer
- 2014
-
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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| 3. |
- Comina, German, et al.
(författare)
-
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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| 4. |
- 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
-
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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| 5. |
- 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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| 6. |
- 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
-
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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| 7. |
- 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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| 8. |
- 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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| 9. |
- Iqbal, Zafar, et al.
(författare)
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Spectral Fingerprinting on a Standard Mobile Phone
- 2010
-
Ingår i: Journal of Sensors. - : Hindawi. - 1687-725X .- 1687-7268. ; 2010, s. 381796-
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Tidskriftsartikel (refereegranskat)abstract
- Spectral fingerprinting of chemical indicators, using computer screens as light sources and web cameras as imaging detectors, is an emerging approach for chemical sensing with the potential to coexist in common consumer electronic devices.The migration of this technique to mobile phones is key to extend this sensing approach to the most ubiquitous and familiar type of instrumentation. Here, we investigate the feasibility and performance of spectral fingerprinting on reference samples using a standard mobile phone as a complete measuring platform, where the screen provides controlled illumination while the front camera is the imaging detector. Key elements for the execution of such experiments are the software design, the definition of the sample layout, the type of alignment between the phone and the sample, and the influence of ambient illumination. This paper demonstrates the feasibility of reflectance fingerprinting on standard mobile phones and identify the operating conditions of the key parameters that produce an adequate evaluation performance.
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| 10. |
- Macken, Stephen, et al.
(författare)
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Colour moire interferometry for physical sensing using a standard web camera
- 2010
-
Ingår i: Measurement science and technology. - : Iop Publishing Ltd. - 0957-0233 .- 1361-6501. ; 21:10, s. 105305-
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Tidskriftsartikel (refereegranskat)abstract
- Digital moire patterns are an effect seen in digital pictures when a high-contrast periodic object being imaged interferes with the periodic image detector in the camera. This is often an undesired effect, which is usually removed through various filtering processes. However in this work we demonstrate the ability to use a deliberately created moire pattern to measure the physical distance of an object from a web camera with a resolution of 131 mu m. This measurement principle is then adapted to measure weight as a ubiquitous scale with a resolution of 240 mu g.
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| 11. |
- Macken, Stephen, 1982-
(författare)
-
Integrated Optical Solutions for Ubiquitous Sensing
- 2010
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ubiquitous chemical sensing aims at exploiting consumer electronic devices as temporary chemical sensing platforms. These devices are a highly disseminated infrastructure, not presently being exploited for chemical sensing purposes. The goal of the ubiquitous chemical sensing field is to create the methodologies and adapted devices to profit from this unexploited resource.DVD drives, flat bed scanners and computer screens used in combination with web cameras, and mobile phones have been demonstrated as measuring platforms, during the past 10 years.In particular the combination of computer screens with web cameras, a technique called the computer screen photo-assisted technique (CSPT), is the most versatile approach to support multiple types of optical detection phenomena, and together with mobile phones are the most ubiquitous type of platforms.The versatility of CSPT comes from the ease with which one can configure a spectrally controlled, 2D micro-positioned, linearly polarized, wide angle and internally modulated illumination with a programmable screen, just by controlling the displayed contents. Concurrently, the imaging devices in CSPT enable one to capture arbitrary assay layouts, the evaluation of which can then be numerically customized.The full exploitation of the CSPT platform requires optically adapted sensing interfaces and specialized methods, in order to increase sensitivity and make use of all available information, for a thorough and complete chemical sensing analysis. In this thesis I have explored the foundations of CSPT sensing on integrated devices, developing methods and sensing’s interfaces that provide enhanced optical detection customized to the CSPT platform.
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| 12. |
- Martinelli, E, et al.
(författare)
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Odor Processing with an experimental model of Olfactory epithelium and bulb
- 2011
-
Ingår i: Chemical Senses. - : Oxford University Press. - 0379-864X .- 1464-3553. ; 36:1, s. E4-E4
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Artificial olfaction was introduced as a model tool to investigateolfaction properties [1]. Nonetheless, the only analogy between the natural and the artificial system lies just in the selectivity proper- ties of the receptors. The implementation of more sophisticated fea- tures such as the large number of receptors and the glomerular layer have been hampered by technical difficulties related to the manage- ment of large numbers of simultaneous signals.As demonstrated in the past, optical imaging is a read-out tech- nique for sensors development that can provide large sensor arrays [2]. On that basis, we recently introduced an artificial olfaction sys- tem based on the imaging of a continuous layer of chemical indi- cators [3]. In this situation an image sensor provides a segmentation of the whole sensing layer in a number of elementary units corre- sponding to the pixels of the image. Eventually, since it is possible to evaluate the optical properties of every single pixel, each pixel of the image may correspond to an individual sensor. In this regard, even low-resolution images may easily result in thousands of independ- ent sensing units.In our system a collection of arbitrarily shaped regions of color indicators is illuminated by a controlled light source; the optical characteristics of each pixel of the image are measured by a camera yielding the light intensities in the three channels red, green, and blue. The combination of illumination sequence and cameraread-out results in a fingerprint encoding the optical properties of the sensing layer portioned in image pixels. Even a simple clas- sification of these fingerprints assigns each pixel to a class, and each class contains pixels carrying the same color indicator. This behav- ior resembles the association between ORNs carrying the same chemical receptors into the same glomerulus [4]. On the basis of this analogy it is straightforward to describe the layer of indicators as an artificial epithelium, pixels of the image as artificial olfactory neu- rons, and the classes provided by the classifier as an abstract rep- resentation of artificial glomeruli.This system thus allows the generation of a complex model of olfaction, including glomerular compartmentalization [5], which is then applied to data generated by the exposure to pure and mixed gases. Results show that such a model enhances the discrimination of pure and mixed odors. Eventually, such a platform, apart from evidencing the similarities between natural and artificial olfactory systems, is also proposed as a practical tool to test olfactory models.1. K. Persaud and G. Dodds, Nature 299 (1982) 3522. Dickinson et al., Nature 382 (1996) 6973. C. Di Natale et al., PLoS ONE 3 (2008) 31394. P. Mombaerts, Annu Rev Neurosci 22 (1999) 4875. D. Schild and H. Riedel, Biophysical Journal, 61 (1992) 704
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| 13. |
- Preechaburana, Pakorn, et al.
(författare)
-
Biosensing with cell phones
- 2014
-
Ingår i: Trends in Biotechnology. - : Elsevier. - 0167-7799 .- 1879-3096. ; 32:7, s. 351-355
-
Forskningsöversikt (refereegranskat)abstract
- Continued progress in cell-phone devices has made them powerful mobile computers, equipped with sophisticated, permanent physical sensors embedded as the default configuration. By contrast, the incorporation of permanent biosensors in cell-phone units has been prevented by the multivocal nature of the stimuli and the reactions involved in biosensing and chemical sensing. Biosensing with cell phones entails the complementation of biosensing devices with the physical sensors and communication and processing capabilities of modern cell phones. Biosensing, chemical-sensing, environmental-sensing, and diagnostic capabilities would thus be supported and run on the residual capacity of existing cell-phone infrastructure. The technologies necessary to materialize such a scenario have emerged in different fields and applications. This article addresses the progress on cell-phone biosensing, the specific compromises, and the blend of technologies required to craft biosensing on cell phones.
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| 14. |
- Preechaburana, Pakorn, et al.
(författare)
-
Disposable total internal reflection fluorescence lab-on-a-chip for medical diagnosis
- 2012
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Lab-on-a-chip detection of fluorescence transduced chemical stimuli is demonstrated using fluidics and optical coupling disposable elements in a configuration compatible with distributed diagnosis.Disposable optical elements are designed to separate excitation by total internal reflection using regular glass slides as optical light guide and fluidics support, while high dynamic range image acquisition with consumer cameras complement the platform to support a broad range of responses with a same configuration. Complementary tone mapping procedures are introduced to systematically double the sensitivity for selected range intervals.Chemical sensitization to free fucose, a diagnostic marker for liver cirrhosis and several cancer forms, illustrates the platform capabilities for diagnosis targets.
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| 15. |
- Preechaburana, Pakorn, et al.
(författare)
-
Embedded Adaptive Optics for Ubiquitous Lab-on-a-Chip Readout on Intact Cell Phones
- 2012
-
Ingår i: Sensors. - : MDPI. - 1424-8220. ; 12:7, s. 8586-8600
-
Tidskriftsartikel (refereegranskat)abstract
- The evaluation of disposable lab-on-a-chip (LOC) devices on cell phones is an attractive alternative to migrate the analytical strength of LOC solutions to decentralized sensing applications. Imaging the micrometric detection areas of LOCs in contact with intact phone cameras is central to provide such capability. This work demonstrates a disposable and morphing liquid lens concept that can be integrated in LOC devices and refocuses micrometric features in the range necessary for LOC evaluation using diverse cell phone cameras. During natural evaporation, the lens focus varies adapting to different type of cameras. Standard software in the phone commands a time-lapse acquisition for best focal selection that is sufficient to capture and resolve, under ambient illumination, 50 mu m features in regions larger than 500 x 500 mu m(2). In this way, the present concept introduces a generic solution compatible with the use of diverse and unmodified cell phone cameras to evaluate disposable LOC devices.
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| 16. |
- Preechaburana, Pakorn, et al.
(författare)
-
Fabrication of monolithic 3D micro-systems
- 2011
-
Ingår i: LAB ON A CHIP. - : Royal Society of Chemistry. - 1473-0197. ; 11:2, s. 288-295
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Tidskriftsartikel (refereegranskat)abstract
- This article describes a method and platform for fast prototyping of monolithic 3D microstructures, capable of producing arbitrary positive, negative and suspended 3D geometries, as well as sealed spaces and aligned 3D geometries using standard photoresists and few fabrication steps. Here a microfabrication method employing a mask-less micro-projection lithography platform, which co-exists on a routine fluorescence microscope, has been refined to produce a variety of 3D microstructures with up to 5 mm spatial resolutions and 10 : 1 aspect ratios, as well as its integration within macroscopic areas of several millimetres with up to 30 mu m spatial resolutions.
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| 17. |
- Preechaburana, P., et al.
(författare)
-
HDR imaging evaluation of a NT-proBNP test with a mobile phone.
- 2011
-
Ingår i: Biosensors & bioelectronics. - : Elsevier BV. - 0956-5663 .- 1873-4235. ; 26:5, s. 2107-2113
-
Tidskriftsartikel (refereegranskat)abstract
- The determination of NT-proBNP levels is key for the monitoring of patients with diagnosed heart failure and it is a routine measurement typically performed at health care centers, which would benefit from decentralized alternatives. Here we investigate the quantitative evaluation of a well-established NT-proBNP test using a standard mobile phone (Nokia 6720) as measuring platform rather than a dedicated instrument. A Java ME software developed for this application controls the illumination and imaging of the proBNP test under defined time intervals, which enables the composition of multi-exposure sets that are processed as high dynamic range (HDR) images for contrast enhancement. The results show that HDR processing significantly increases the sensitivity and resolution of the technique achieving a performance within the diagnostics range. These results demonstrate the feasibility to exploit a ubiquitous device to decentralize the evaluation of a routine test and identify key processing alternatives to bring the performance of such systems within the diagnostics range.
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| 18. |
- Preechaburana, Pakorn
(författare)
-
Optical devices and methods for distributed lab-on-a-chip analyses
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lab-on-a-chip (LOC) technologies entail the miniaturization of analytical systems, and the reduction of required sample and reagent volumes. LOC devices offer compact alternatives to classical instrumentation while delivering comparable performance and disposable formats. These aspects make disposable LOC a clear candidate to support distributed chemical sensing applications; however, the need of accessory services and readout obstructs the materialization of pervasively distributed LOC solutions.In this thesis methods and devices to solve this problem are investigated. A distinctive aspect of this work is the pursuit of solutions based on disposable LOC elements specifically conceived to exploit ubiquitous infrastructure for readout and evaluation.Consumer electronic devices, such as cell phones are ubiquitous platforms with residual capabilities that can be used for chemical sensing, if properly interfaced. This work investigates elements and tools needed to empower cell phones as readers of disposable LOC devices and commercial disposable tests.Access to flexible fabrication of LOC devices at low cost is an important requisite for testing ideas and implementing customized solutions. A first contribution in this thesis is the development of a platform for mask less fabrication of 3D microstructures, which coexists on a routine fluorescence microscope. This microscope projection lithography system (MPLS) is capable of controlled 3D micro structuring, including cavities and cantilever geometries, and the sealing of monolithic micro cavities to glass substrates as well as the connection to large scale service areas. This fabrication platform and other fabrication methods were used along this thesis to provide disposable optical and fluidic components.Besides custom-made LOC solutions there are well-established commercial disposable devices, which are essentially compatible with decentralized diagnosis, except for the use of specialized readers that confine them to medical centers. The implementation of high dynamic range (HDR) imaging with standard cell phones, using the phone screen to control exposure, shows that sensitivity and resolution can be boosted to permit robust evaluation of this type of disposable tests, in decentralized scenarios.Solutions employing commercial tests, which have not been designed for cell phone evaluation, are typically suboptimal and the investigation of customized LOC components occupies a central role in this thesis. Accordingly, one important aspect to evaluate LOC devices in compact configurations is to be able to image the LOC at a close distance from the phone camera, a condition for which phones cameras are not able to focus.In addition, different phone brands and models have different optical specifications, and a practical refocusing solution should adapt to all of them. In this work an adaptive lens concept, complemented by phone time-lapse acquisition, which can be integrated in disposable LOCs, is demonstrated.The implementation of sensitive detection methods, such as surface plasmon resonance (SPR), which is compatible with label free protocols that simplify sample conditioning, is central to the materialization of ubiquitous LOCs readable with cell phones. In this thesis a disposable optical coupler, conditioning illumination taken from the phone screen, is used to create an angle resolved SPR signal from a LOC, which is read with the phone front camera. Tested performance is comparable with commercial compact SPR modules and detection of β2 microglobulin, which is an established marker for cancer, inflammatory disorders, and kidney disease, is within the diagnostics range for blood and urine.Finally, fluorescence detection within classical LOC devices is tailored to be detectable with consumer cameras. In this case a disposable optical coupler and fluidics is designed to condition laser illumination into total internal reflection excitation, while DSLR and phone cameras capture optically separated fluorescence. The system configuration supports a broad dynamic range and HDR imaging enables localized resolution boost at selected detection ranges. Detection of free fucose, a diagnostic marker for liver cirrhosis and several cancer forms, is shown feasible with a HDR implementation, as one last example of practical LOC detection schemes for decentralized scenarios.
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| 19. |
- Preechaburana, Pakorn, et al.
(författare)
-
Surface Plasmon Resonance Chemical Sensing on Cell Phones
- 2012
-
Ingår i: Angewandte Chemie International Edition. - : Wiley Online Library. - 1433-7851 .- 1521-3773. ; 51:46, s. 11585-11588
-
Tidskriftsartikel (refereegranskat)abstract
- Chemosensing based on angle-resolved surface plasmon resonance is demonstrated on intact cell phones using a disposable optical coupler and software to configure illumination and acquisition. This coupler operates on different cell phones and is applied for classical affinity assays with commercial chips and custom-made tests with embedded calibration. Measured performance (2.14x10−6 refractive index units) is comparable with compact SPR systems.
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