3D-Printed Graphene Electrodes Applied in an Impedimetric Electronic Tongue for Soil Analysis

The increasing world population leads to the growing demand for food production without expanding cultivation areas. In this sense, precision agriculture optimizes the production and input usage by employing sensors to locally monitor plant nutrient within agricultural fields. Here, we have used an electronic tongue sensing device based on impedance spectroscopy to recognize distinct soil samples (sandy and clayey) enriched with macronutrients. The e-tongue setup consisted of an array of four sensing units formed by layer-by-layer (LbL) films deposited onto 3D-printed graphene-based interdigitated electrodes (IDEs). The IDEs were fabricated in 20 min using the fused deposition modeling process and commercial polylactic acid-based graphene filaments. The e-tongue comprised one bare and three IDEs functionalized with poly(diallyldimethylammonium chloride) solution/copper phthalocyanine-3,4′,4′′,4′′′-tetrasulfonic acid tetrasodium salt (PDDA/CuTsPc), PDDA/montmorillonite clay (MMt-K), and PDDA/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) LbL films. Control samples of sandy and clayey soils were enriched with different concentrations of nitrogen (N), phosphorus (P), and potassium (K) macronutrients. Sixteen soil samples were simply diluted in water and measured using electrical impedance spectroscopy, with data analyzed by principal component analysis. All soil samples were easily distinguished without pre-treatment, indicating the suitability of 3D-printed electrodes in e-tongue analysis to distinguish the chemical fertility of soil samples. Our results encourage further investigations into the development of new tools to support precision agriculture.

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Polyelectrolyte Based Sensors as Key to Achieve Quantitative Electronic Tongues: Detection of Triclosan on Aqueous Environmental Matrices

Nanomaterials ◽

10.3390/nano10040640 ◽

2020 ◽

Vol 10 (4) ◽

pp. 640

Author(s):

Cátia Magro ◽

Paulo Zagalo ◽

João Pereira-da-Silva ◽

Eduardo Pires Mateus ◽

Alexandra Branco Ribeiro ◽

...

Keyword(s):

Continuous Monitoring ◽

Mineral Water ◽

Electronic Tongue ◽

Principal Component ◽

Electrical Impedance Spectroscopy ◽

Layer By Layer ◽

Environmental Matrices ◽

Film Stability ◽

Lbl Films ◽

Water And Wastewater

Triclosan (TCS) is a bacteriostatic used in household items that promotes antimicrobial resistance and endocrine disruption effects both to humans and biota, raising health concerns. In this sense, new devices for its continuous monitoring in complex matrices are needed. In this work, sensors, based on polyelectrolyte layer-by-layer (LbL) films prepared onto gold interdigitated electrodes (IDE), were studied. An electronic tongue array, composed of (polyethyleneimine (PEI)/polysodium 4-styrenesulfonate (PSS))5 and (poly(allylamine hydrochloride/graphene oxide)5 LbL films together with gold IDE without coating were used to detect TCS concentrations (10−15–10−5 M). Electrical impedance spectroscopy was used as means of transduction and the obtained data was analyzed by principal component analysis (PCA). The electronic tongue was tested in deionized water, mineral water and wastewater matrices showing its ability to (1) distinguish between TCS doped and non-doped solutions and (2) sort out the TCS range of concentrations. Regarding film stability, strong polyelectrolytes, as (PEI/PSS)n, presented more firmness and no significant desorption when immersed in wastewater. Finally, the PCA data of gold IDE and (PEI/PSS)5 sensors, for the mineral water and wastewater matrices, respectively, showed the ability to distinguish both matrices. A sensitivity value of 0.19 ± 0.02 per decade to TCS concentration and a resolution of 0.13 pM were found through the PCA second principal component.

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3D-Printed Bioreactor with Integrated Impedance Spectroscopy for Cell Barrier Monitoring

10.31224/osf.io/updtw ◽

2021 ◽

Author(s):

Matthias Wessling

Keyword(s):

Cell Culture ◽

Epithelial Cell ◽

Impedance Spectroscopy ◽

Indium Tin Oxide ◽

Electric Circuit ◽

Electrical Impedance Spectroscopy ◽

Oxide Glass ◽

Epithelial Cell Line ◽

Scientific Institutions ◽

3D Printed

Cell culture experiments often suffer from limited commercial availability of laboratory-scale bioreactors, which allow experiments to be conducted under flow conditions and additional online monitoring techniques. A novel 3D-printed bioreactor with a homogeneously distributed flow field enabling epithelial cell culture experiments and online barrier monitoring by integrated electrodes through electrical impedance spectroscopy (EIS) is presented. Transparent and conductive indium tin oxide glass as current-injecting electrodes allows direct visualization of the cells, while measuring EIS simultaneously. The bioreactor's design considers the importance of a homogeneous electric field by placing the voltage pick-up electrodes in the electrical field. The device's functionality is demonstrated by the cultivation of the epithelial cell line Caco-2 under continuous flow and monitoring of the cell layer by online EIS. The collected EIS data were fitted by an equivalent electric circuit, resulting in the cell layer's resistance and capacitance. This data is used to monitor the cell layer's reaction to ethylene glycol-bis-(2-aminoethyl ether)-N,N,N′,N′-tetraacetic acid and forskolin. These two model substances show the power of impedance spectroscopy as a non-invasive way to characterize cell barriers. In addition, the bioreactor design is available as a print-ready file in the Appendix, enabling its use for other scientific institutions.

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Predictive Mapping of Soil Properties for Precision Agriculture Using Geographic Information System (GIS) Based Geostatistics Models

Modern Applied Science ◽

10.5539/mas.v13n10p60 ◽

2019 ◽

Vol 13 (10) ◽

pp. 60 ◽

Cited By ~ 5

Author(s):

John Kingsley ◽

Solomon Odafe Lawani ◽

Ayito Okon Esther ◽

Kebonye Michael Ndiye ◽

Ogeh Joseph Sunday ◽

...

Keyword(s):

Spatial Variability ◽

Soil Properties ◽

Precision Agriculture ◽

Soil Analysis ◽

Soil Samples ◽

Soil Parameters ◽

Available Phosphorus ◽

Predictive Tool ◽

Large Variability ◽

North East

In precision Agriculture, geostatistical methods as a predictive tool have been extensively utilized. The approach estimates soil properties spatial variability and dependency. This study was carried out in Ovia north east Local Government Area of Edo State of Nigeria in order to map soil properties (Sand, Clay, pH, OC, P, N and CEC) and redict their spatial variability. Twenty-nine (29) soil samples were collected randomly from Typic Kandiudults soil type under three different land use, teak forest plantation, shrub, and arable farm. The soil samples were air-dried and passed through a 2 mm sieve before being analyzed for pH(CaCl2), SOC, Sand, Clay, Phosphorus, Nitrogen, and CEC. Generated data were statistically and geostatistically computed to explain the spatial variability of soil properties. The traditional method of soil analysis and interpretation are tedious, time-consuming with escalating budgets thus geostatical approach. Available phosphorus yielded large variability with CV=57.08% followed by clay content with CV=49.03%. Spherical, Gaussian, Hole Effect model, Stable, Exponential and Circular models were fitted for all the soil parameters. The result revealed that soil pH, Sand content, TN and CEC were moderate spatially autocorrelated with nugget/sill value of 0.32, 0.21, 0.49 and 0.30 respectively.  SOC also gave a moderate spatially autocorrelated with nugget/sill value of 0.44. And Clay and Available phosphorus were strong spatially autocorrelated with nugget/sill value of 0.15 and 0.13 respectively. Cross-validation of the output maps using the semivariogram showed that the interpolation models are superior to assuming mean for any unsampled area. The output maps will help soil users within the area to proffer best management technology to improve crop, fiber and water production.   

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Two-Compartment Capsular Devices for Oral Pulsatile Delivery 3D-Printed by Fused Deposition Modeling

10.26226/morressier.57d6b2b6d462b8028d88d9d6 ◽

2016 ◽

Author(s):

Federica Casati

Keyword(s):

Fused Deposition Modeling ◽

Fused Deposition ◽

Deposition Modeling ◽

3D Printed ◽

Pulsatile Delivery

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Biodegradable 3D Printed Polymer Microneedles for Transdermal Drug Delivery

10.26434/chemrxiv.5851950.v1 ◽

2018 ◽

Cited By ~ 1

Author(s):

Michael A. Luzuriaga ◽

Danielle R. Berry ◽

John C. Reagan ◽

Ronald A. Smaldone ◽

Jeremiah J. Gassensmith

Keyword(s):

Drug Delivery ◽

3D Printing ◽

Transdermal Drug Delivery ◽

Fused Deposition Modeling ◽

Fused Deposition ◽

Modeling Software ◽

Deposition Modeling ◽

3D Printed ◽

Microfabrication Technique ◽

Mechanical Strengths

Biodegradable polymer microneedle (MN) arrays are an emerging class of transdermal drug delivery devices that promise a painless and sanitary alternative to syringes; however, prototyping bespoke needle architectures is expensive and requires production of new master templates. Here, we present a new microfabrication technique for MNs using fused deposition modeling (FDM) 3D printing using polylactic acid, an FDA approved, renewable, biodegradable, thermoplastic material. We show how this natural degradability can be exploited to overcome a key challenge of FDM 3D printing, in particular the low resolution of these printers. We improved the feature size of the printed parts significantly by developing a post fabrication chemical etching protocol, which allowed us to access tip sizes as small as 1 μm. With 3D modeling software, various MN shapes were designed and printed rapidly with custom needle density, length, and shape. Scanning electron microscopy confirmed that our method resulted in needle tip sizes in the range of 1 – 55 µm, which could successfully penetrate and break off into porcine skin. We have also shown that these MNs have comparable mechanical strengths to currently fabricated MNs and we further demonstrated how the swellability of PLA can be exploited to load small molecule drugs and how its degradability in skin can release those small molecules over time.

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Electrical Impedance Spectroscopy Estimation of Water Content in Leaves and Stems of White Birch (Betula platyphylla) Under Flooding Stress

CHINESE BULLETIN OF BOTANY ◽

10.3724/sp.j.1259.2014.00105 ◽

2014 ◽

Vol 49 (1) ◽

pp. 105 ◽

Cited By ~ 1

Author(s):

Meng Yu ◽

Gong Ruijuan ◽

Di Bao ◽

Xiang Diying ◽

Zhang Gang ◽

...

Keyword(s):

Impedance Spectroscopy ◽

Water Content ◽

Electrical Impedance ◽

Electrical Impedance Spectroscopy ◽

Betula Platyphylla ◽

White Birch ◽

Flooding Stress

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Design of a 3D-printed hand prosthesis featuring articulated bio-inspired fingers

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1177/0954411920980889 ◽

2020 ◽

pp. 095441192098088

Author(s):

Juan Sebastian Cuellar ◽

Dick Plettenburg ◽

Amir A Zadpoor ◽

Paul Breedveld ◽

Gerwin Smit

Keyword(s):

3D Printing ◽

Design Principles ◽

Prosthetic Hand ◽

Hand Prosthesis ◽

Fused Deposition ◽

Pinch Force ◽

Actuation System ◽

3D Printed ◽

Energy Dissipated ◽

Dual Material

Various upper-limb prostheses have been designed for 3D printing but only a few of them are based on bio-inspired design principles and many anatomical details are not typically incorporated even though 3D printing offers advantages that facilitate the application of such design principles. We therefore aimed to apply a bio-inspired approach to the design and fabrication of articulated fingers for a new type of 3D printed hand prosthesis that is body-powered and complies with basic user requirements. We first studied the biological structure of human fingers and their movement control mechanisms in order to devise the transmission and actuation system. A number of working principles were established and various simplifications were made to fabricate the hand prosthesis using a fused deposition modelling (FDM) 3D printer with dual material extrusion. We then evaluated the mechanical performance of the prosthetic device by measuring its ability to exert pinch forces and the energy dissipated during each operational cycle. We fabricated our prototypes using three polymeric materials including PLA, TPU, and Nylon. The total weight of the prosthesis was 92 g with a total material cost of 12 US dollars. The energy dissipated during each cycle was 0.380 Nm with a pinch force of ≈16 N corresponding to an input force of 100 N. The hand is actuated by a conventional pulling cable used in BP prostheses. It is connected to a shoulder strap at one end and to the coupling of the whiffle tree mechanism at the other end. The whiffle tree mechanism distributes the force to the four tendons, which bend all fingers simultaneously when pulled. The design described in this manuscript demonstrates several bio-inspired design features and is capable of performing different grasping patterns due to the adaptive grasping provided by the articulated fingers. The pinch force obtained is superior to other fully 3D printed body-powered hand prostheses, but still below that of conventional body powered hand prostheses. We present a 3D printed bio-inspired prosthetic hand that is body-powered and includes all of the following characteristics: adaptive grasping, articulated fingers, and minimized post-printing assembly. Additionally, the low cost and low weight make this prosthetic hand a worthy option mainly in locations where state-of-the-art prosthetic workshops are absent.

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Quality Control in 3D Printing: Accuracy Analysis of 3D-Printed Models of Patient-Specific Anatomy

Materials ◽

10.3390/ma14041021 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1021

Author(s):

Bernhard Dorweiler ◽

Pia Elisabeth Baqué ◽

Rayan Chaban ◽

Ahmed Ghazy ◽

Oroa Salem

Keyword(s):

Wall Thickness ◽

Large Scale ◽

Fused Deposition Modeling ◽

Vascular Anatomy ◽

3D Models ◽

Patient Specific ◽

Stl File ◽

Fused Deposition ◽

3D Printed ◽

The Mean

As comparative data on the precision of 3D-printed anatomical models are sparse, the aim of this study was to evaluate the accuracy of 3D-printed models of vascular anatomy generated by two commonly used printing technologies. Thirty-five 3D models of large (aortic, wall thickness of 2 mm, n = 30) and small (coronary, wall thickness of 1.25 mm, n = 5) vessels printed with fused deposition modeling (FDM) (rigid, n = 20) and PolyJet (flexible, n = 15) technology were subjected to high-resolution CT scans. From the resulting DICOM (Digital Imaging and Communications in Medicine) dataset, an STL file was generated and wall thickness as well as surface congruency were compared with the original STL file using dedicated 3D engineering software. The mean wall thickness for the large-scale aortic models was 2.11 µm (+5%), and 1.26 µm (+0.8%) for the coronary models, resulting in an overall mean wall thickness of +5% for all 35 3D models when compared to the original STL file. The mean surface deviation was found to be +120 µm for all models, with +100 µm for the aortic and +180 µm for the coronary 3D models, respectively. Both printing technologies were found to conform with the currently set standards of accuracy (<1 mm), demonstrating that accurate 3D models of large and small vessel anatomy can be generated by both FDM and PolyJet printing technology using rigid and flexible polymers.

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