scholarly journals Microfluidic Mixer with Automated Electrode Switching for Sensing Applications

Chemosensors ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 13 ◽  
Author(s):  
Maria L. Braunger ◽  
Igor Fier ◽  
Varlei Rodrigues ◽  
Paulo E. Arratia ◽  
Antonio Riul
Keyword(s):  
Printed Circuit Board ◽  
Electronic Tongue ◽  
Microfluidic Devices ◽  
Circuit Board ◽  
Physical Interaction ◽  
Layer By Layer ◽  
Passive Mixer ◽  
Microfluidic Mixer ◽  
Sensing Applications ◽  
Food And Beverage

An electronic tongue (e-tongue) is a multisensory system usually applied to complex liquid media that uses computational/statistical tools to group information generated by sensing units into recognition patterns, which allow the identification/distinction of samples. Different types of e-tongues have been previously reported, including microfluidic devices. In this context, the integration of passive mixers inside microchannels is of great interest for the study of suppression/enhancement of sensorial/chemical effects in the pharmaceutical, food, and beverage industries. In this study, we present developments using a stereolithography technique to fabricate microfluidic devices using 3D-printed molds for elastomers exploring the staggered herringbone passive mixer geometry. The fabricated devices (microchannels plus mixer) are then integrated into an e-tongue system composed of four sensing units assembled on a single printed circuit board (PCB). Gold-plated electrodes are designed as an integral part of the PCB electronic circuitry for a highly automated platform by enabling faster analysis and increasing the potential for future use in commercial applications. Following previous work, the e-tongue sensing units are built functionalizing gold electrodes with layer-by-layer (LbL) films. Our results show that the system is capable of (i) covering basic tastes below the human gustative perception and (ii) distinguishing different suppression effects coming from the mixture of both strong and weak electrolytes. This setup allows for triplicate measurements in 12 electrodes, which represents four complete sensing units, by automatically switching all electrodes without any physical interaction with the sensor. The result is a fast and reliable data acquisition system, which comprises a suitable solution for monitoring, sequential measurements, and database formation, being less susceptible to human errors.

A Comparison of Immersion Gold and Tin Surface Finishes on Sensing Electrodes for PCB Environmental Saltwater Concentration Sensors

2016 ◽  
Vol 2016 (1) ◽  
pp. 000557-000562
Author(s):  
Robert N. Dean ◽  
Frank T. Werner ◽  
Michael J. Bozack
Keyword(s):  
Surface Finish ◽  
Printed Circuit Board ◽  
Chemical Constituents ◽  
Low Cost ◽  
Circuit Board ◽  
Testing Environment ◽  
Printed Circuit ◽  
Sensor Performance ◽  
Sensing Applications ◽  
Surface Finishes

Abstract Printed circuit board (PCB) sensors using low-cost commercial printed circuit board fabrication processes have been demonstrated for environmental sensing applications. One configuration of these sensors uses exposed electrodes to measure saltwater concentration in freshwater/seawater mixtures, through monitoring the resistance between the electrodes when they are immersed in the saltwater/freshwater solution. The lowest cost commercial PCB processes use an immersion Sn HASL surface finish on exposed copper cladding, including the sensing electrodes. This commercial PCB process has been demonstrated to make an effective, low-cost, short-lifetime sensor for saltwater concentration testing. The Sn finish, however, may not be optimal for this application. Sn oxidizes, which can interfere with sensor performance. Additionally, Sn and Sn oxides are potentially reactive with chemical constituents in seawater and seawater/freshwater solutions. An immersion Au (ENIG) surface finish is certainly less reactive with the atmosphere and chemicals likely present in the testing environment. However, an immersion Au finish increases the cost of the sensors by 30% to 40%. To investigate if the possible benefits of the more expensive Au surface finish are worth the extra expense, a study was performed where identical PCB sensors were procured from a commercial vendor with their standard low-cost Sn HASL finish and with their standard ENIG surface finish. Both sets of sensors were then evaluated in concentrations of seawater and freshwater, from 0% to 100% seawater concentration, using freshwater samples from a natural freshwater source near the coast where the seawater was obtained. Testing demonstrated an insignificant difference in sensor performance between the Sn HASL and the ENIG coated sensing electrodes. The results of this investigation indicated that for applications where the sensors will not be used for long periods of time, the added expense of an immersion Au surface finish is not worth the added cost.

scholarly journals AlN-on-Si Square Diaphragm Piezoelectric Micromachined Ultrasonic Transducer with Extended Range of Detection

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 913 ◽  
Author(s):  
Suresh Alasatri ◽  
Libor Rufer ◽  
Joshua En-Yuan Lee
Keyword(s):  
Printed Circuit Board ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Circuit Board ◽  
Detection Range ◽  
Range Finding ◽  
Sensing Applications ◽  
Current State ◽  
Wire Bonds ◽  
Extended Range

We present aluminum nitride (AlN) on silicon (Si) CMOS-compatible piezoelectric micromachined ultrasonic transducers (pMUTs) with an extended detection range of up to 140 cm for touchless sensing applications. The reported performance surpasses the current state-of-art for AlN-based pMUTs in terms of the maximum range of detection using just a pair of pMUTs (as opposed to an array of pMUTs). The extended range of detection has been realized by using a larger diaphragm allowed by fabricating a thicker diaphragm than most other pMUTs reported to date. Using a pair of pMUTs, we experimentally demonstrate the capability of range-finding by correlating the time-of-flight (TOF) between the transmit (TX) and receive (RX) pulse. The results were obtained using an experimental setup where the MEMS chip was interconnected with a customized printed circuit board (PCB) using Al wire bonds.

Microfluidic Devices on Printed Circuit Board

2002 ◽  
pp. 185-217 ◽  
Author(s):  
Stefan Richter ◽  
Nam-Trung Nguyen ◽  
Ansgar Wego ◽  
Lienhard Pagel
Keyword(s):  
Printed Circuit Board ◽  
Microfluidic Devices ◽  
Circuit Board ◽  
Printed Circuit

scholarly journals Toward Medical Devices With Integrated Mechanisms, Sensors, and Actuators Via Printed-Circuit MEMS

2017 ◽  
Vol 11 (1) ◽  
Author(s):  
Joshua Gafford ◽  
Tommaso Ranzani ◽  
Sheila Russo ◽  
Alperen Degirmenci ◽  
Samuel Kesner ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
The Body ◽  
Circuit Board ◽  
Layer By Layer ◽  
Flexible Systems ◽  
Sensors And Actuators ◽  
Printed Circuit ◽  
Minimally Invasive Surgical ◽  
Layer Manufacturing ◽  
End Effectors

Recent advances in medical robotics have initiated a transition from rigid serial manipulators to flexible or continuum robots capable of navigating to confined anatomy within the body. A desire for further procedure minimization is a key accelerator for the development of these flexible systems where the end goal is to provide access to the previously inaccessible anatomical workspaces and enable new minimally invasive surgical (MIS) procedures. While sophisticated navigation and control capabilities have been demonstrated for such systems, existing manufacturing approaches have limited the capabilities of millimeter-scale end-effectors for these flexible systems to date and, to achieve next generation highly functional end-effectors for surgical robots, advanced manufacturing approaches are required. We address this challenge by utilizing a disruptive 2D layer-by-layer precision fabrication process (inspired by printed circuit board manufacturing) that can create functional 3D mechanisms by folding 2D layers of materials which may be structural, flexible, adhesive, or conductive. Such an approach enables actuation, sensing, and circuitry to be directly integrated with the articulating features by selecting the appropriate materials during the layer-by-layer manufacturing process. To demonstrate the efficacy of this technology, we use it to fabricate three modular robotic components at the millimeter-scale: (1) sensors, (2) mechanisms, and (3) actuators. These modules could potentially be implemented into transendoscopic systems, enabling bilateral grasping, retraction and cutting, and could potentially mitigate challenging MIS interventions performed via endoscopy or flexible means. This research lays the ground work for new mechanism, sensor and actuation technologies that can be readily integrated via new millimeter-scale layer-by-layer manufacturing approaches.

scholarly journals Influence of the Flow Rate in an Automated Microfluidic Electronic Tongue Tested for Sucralose Differentiation

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6194
Author(s):  
Maria L. Braunger ◽  
Igor Fier ◽  
Flávio M. Shimizu ◽  
Anerise de Barros ◽  
Varlei Rodrigues ◽  
...  
Keyword(s):  
Double Layer ◽  
Flow Rate ◽  
Printed Circuit Board ◽  
Electronic Tongue ◽  
Equivalent Circuit Model ◽  
Principal Component ◽  
Food Product ◽  
Circuit Board ◽  
Raw Data ◽  
Flow Rate Increase

Incorporating electronic tongues into microfluidic devices brings benefits as dealing with small amounts of sample/discharge. Nonetheless, such measurements may be time-consuming in some applications once they require several operational steps. Here, we designed four collinear electrodes on a single printed circuit board, further comprised inside a straight microchannel, culminating in a robust e-tongue device for faster data acquisition. An analog multiplexing circuit automated the signal’s routing from each of the four sensing units to an impedance analyzer. Both instruments and a syringe pump are controlled by dedicated software. The automated e-tongue was tested with four Brazilian brands of liquid sucralose-based sweeteners under 20 different flow rates, aiming to systematically evaluate the influence of the flow rate in the discrimination among sweet tastes sold as the same food product. All four brands were successfully distinguished using principal component analysis of the raw data, and despite the nearly identical sucralose-based taste in all samples, all brands’ significant distinction is attributed to small differences in the ingredients and manufacturing processes to deliver the final food product. The increasing flow rate improves the analyte’s discrimination, as the silhouette coefficient reaches a plateau at ~3 mL/h. We used an equivalent circuit model to evaluate the raw data, finding a decrease in the double-layer capacitance proportional to improvements in the samples’ discrimination. In other words, the flow rate increase mitigates the formation of the double-layer, resulting in faster stabilization and better repeatability in the sensor response.

Laminate Materials for Microfluidic PCBs

2012 ◽  
Vol 2012 (1) ◽  
pp. 000162-000168
Author(s):  
Sarkis Babikian ◽  
Brian Soriano ◽  
G.P. Li ◽  
Mark Bachman
Keyword(s):  
Printed Circuit Board ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Ethylene Vinyl Acetate ◽  
Circuit Board ◽  
Microfluidic Channels ◽  
Printed Circuit ◽  
Laminate Materials ◽  
Integrated Microfluidics ◽  
Functional Components

The printed circuit board (PCB) is a very attractive platform to produce highly integrated highly functional microfluidic devices. We have investigated laminate materials and developed novel fabrication processes to realize low cost and scalable to manufacturing integrated microfluidics on PCBs. In this paper we describe our vision to integrate functional components with microfluidic channels. We also report on the use of Ethylene Vinyl Acetate (EVA) as a laminate for microfluidics. The material was characterized for microfluidic applications and compared with our previously reported laminates: 1002F and Polyurethane.

scholarly journals Integrated microfluidic devices for rapid DNA amplification applicable to diagnostics andpathogendetection in food

2018 ◽  
Author(s):  
Γεωργία Κάπρου
Keyword(s):  
Polymerase Chain Reaction ◽  
Quartz Crystal ◽  
Printed Circuit Board ◽  
Lab On A Chip ◽  
Dna Amplification ◽  
Microfluidic Devices ◽  
Circuit Board ◽  
Chain Reaction ◽  
Printed Circuit ◽  
Polymerase Chain

Η παρούσα διδακτορική διατριβή επικεντρώνεται στην ανάπτυξη μικροαντιδραστήρων για την ενίσχυση δεσοξυριβονουκλεϊνικών οξέων (DNA) με βάση το υπόστρωμα τυπωμένου κυκλώματος (Printed Circuit board,PCB) με χαμηλό κόστος και χαμηλή κατανάλωση ενέργειας, επιτρέποντας τη χρήση τους ακόμη και σε περιοχές με χαμηλούς πόρους, κατάλληλες για ολοκλήρωση σε πλατφόρμες μικροεργαστηρίων σε ψηφίδα (Lab-on-a-Chip, LoC) με εφαρμογή στην ασφάλεια τροφίμων, στα ιατρικά διαγνωστικά και στην περιβαλλοντική παρακολούθηση για την ανίχνευση παθογόνων.Επιτεύχθηκε ταυτόχρονα μεγάλος βαθμός ολοκλήρωσης και χαμηλό κόστος κατασκευής των μικροδιατάξεων αυτών με την επιλογή του PCB ως το κυρίως υπόστρωμα και την ανάπτυξη διαδικασιών κατασκευής συμβατών με την τεχνολογία PCB. Εκτός από την ολοκλήρωση των μικρορευστωνικών δικτύων με ηλεκτρονικά στοιχεία όπως οι αισθητήρες, το PCB επιτρέπει επίσης την ολοκλήρωση μικρoθερμαντικών στοιχείων χαλκού που παρέχουν τις θερμικές ζώνες που είναι απαραίτητες για την ενίσχυση του DNA. Ως εκ τούτου, η χαμηλού κόστους μαζική παραγωγή μικροδιατάξεων ενίσχυσης DNA είναι εφικτή με την χρήση των προτεινόμενων εμπορικά διαθέσιμων υλικών και μεθόδων συμβατών με την τεχνολογία PCB για την κατασκευή των μικροδιατάξεων αυτών στην καλά εδραιωμένη βιομηχανία PCB, αντιμετωπίζοντας έτσι ένα από τα εμπόδια σχετικά με τις μικρορευστωνικές διατάξεις που είναι η εμπορική αξιοποίησή τους.Στην παρούσα διατριβή, κατασκευάστηκαν μικροδιατάξεις ενίσχυσης DNA στατικού θαλάμου και συνεχούς ροής και ελέχθησαν χρησιμοποιώντας πολυάριθμες μεθόδους ενίσχυσης (ισοθερμικές και μη ισοθερμικές) όπως η αλυσιδωτή αντίδραση πολυμεράσης (Polymerase Chain Reaction, PCR), Recombinase Polymerase Amplification (RPA), Helicase Dependent Amplification (HDA) και Loop-mediated Amplification (LAMP). Πρωτόκολλα ενίσχυσης DNA πολύ ταχύτερα σε σχέση με αυτά που διενεργούνται σε συμβατικούς θερμοκυκλοποιητές (μέχρι 20 φορές) διεξήχθησαν εντός των μικροδιατάξεων ενίσχυσης DNA, με συνολική διάρκεια από 2 λεπτά - μία από τις ταχύτερες που αναφέρθηκαν ποτέ - έως 30 λεπτά. Ο σχεδιασμός (βάση αριθμητικών υπολογισμών) των μικροαντιδραστήρων DNA εξασφαλίζει επίσης χαμηλή κατανάλωση ενέργειας (324 J έως 4320 J) η οποία μπορεί να μεταφραστεί στην ανεξάρτητη διεξαγωγή από 65 μέχρι 1000 αντιδράσεων (αναλόγως της μεθόδου ενίσχυσης DNA) με χρήση συνήθους μπαταρίας ισχύος 10.000 mAh (9V).Τέτοιοι μικροαντιδραστήρες ενίσχυσης DNA ολοκληρώθηκαν για πρώτη φορά με ακουστικούς βιοαισθητήρες (Surface Acoustic Wave, SAW). Στην εργασία, παρουσιάζεται μια πλατφόρμα μικροεργαστηρίου σε ψηφίδα LoC βασισμένη στην ακουστική ανίχνευση SAW, εντός της οποίας διεξάγεται η δέσμευση και λύση κυττάρων, και η ενίσχυση του βακτηριακού DNA σε ένα και μόνο θάλαμο για την ανίχνευση ζώντων κυττάρων Σαλμονέλας (που προέρχονται από τεχνητό εμβολιασμό στο γάλα) μέσα σε λιγότερο από 6 ώρες.Παράλληλα, επιτεύχθηκε περαιτέρω βελτίωση της πλατφόρμας LoC με διερεύνηση μεθόδων παθητικοποίησης των τοιχωμάτων μικροκαναλιών για την πρόληψη προσρόφησης βιομορίων στην επιφάνεια των μικροδιατάξεων για τη βελτίωση της ενίσχυσης DNA. Διάλυμα 1% αλβουμίνης Βόιου ορού (Bovine Serum Albumin, BSA) παρατηρήθηκε ότι παθητικοποιεί με βέλτιστο τρόπο τα τοιχώματα και συνεπώς αναστέλλει την προσρόφηση βιομορίων. Παρομοίως, διερευνήθηκε η επιφανειακή ενεργοποίηση των ακουστικών αισθητήρων (Quartz Crystal Microbalance with Dissipation, QCM-D) για επιλεκτική δέσμευση DNA σε πολύπλοκα δείγματα, ανοίγοντας το δρόμο για να χρησιμοποιηθεί η αναπτυγμένη πλατφόρμα με πολύπλοκες μήτρες δειγμάτων. Η χρήση παρεμποδιστικού ρυθμιστικού διαλύματος πριν την εισαγωγή του δείγματος προς ανάλυση στον βιοαισθητήρα βελτιώνει τη διαχωριστική ικανότητα μεταξύ μολυσμένων και μη δειγμάτων όταν χρησιμοποιείται η ανίχνευση μέσω ειδικής πρόσδεσης Αβιδίνης-Βιοτίνης.

Design and Validation of Carbon Nanotube Thin Film Wireless Sensors for pH and Corrosion Monitoring

2008 ◽  
Author(s):  
Kenneth J. Loh ◽  
Jerome P. Lynch
Keyword(s):  
Carbon Nanotube ◽  
Printed Circuit Board ◽  
Ph Sensor ◽  
Corrosion Damage ◽  
Spectroscopic Studies ◽  
Circuit Board ◽  
Corrosion Monitoring ◽  
Layer By Layer ◽  
Ph Sensing ◽  
Resistance Change

Corrosion damage in civil, aeronautical, and mechanical systems poses significant risks to users and occupants while simultaneously burdening owners with costly repairs and maintenance. Although many different sensing technologies are available to monitor corrosion processes, many cannot be easily implemented in field environments due to requiring expensive data acquisition systems and their destructive and intrusive measurement strategies. In this study, a novel layer-by-layer assembled carbon nanotube and poly(aniline)-based nanocomposite pH sensor is developed for monitoring corrosion of metallic and reinforced concrete structures. First, the electrochemical response of the proposed nanocomposite pH sensor is characterized using time-domain two-point resistance probing measurements to validate its resistance change to different pH buffer solutions (1 to 13). Frequency-domain electrical impedance spectroscopic studies and equivalent circuit analyses confirm changes in film resistance to pH. Upon sensor characterization, these nanocomposites are directly deposited onto printed circuit board coil antennas to realize a miniature passive wireless sensor capable of being embedded within structural materials. Preliminary wireless pH sensing results are presented to demonstrate that the wireless sensor’s bandwidth decreases at 3.9 kHz-pH−1 with increasing pH.

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