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Kämpfer Alexandra

Professeur-e HES associé-e

Compétences principales

Professeur-e HES associé-e

Téléphone:+41 32 930 25 53

Haute Ecole Arc - Ingénierie
Espace de l'Europe 11, 2000 Neuchâtel, CH

BSc HES-SO en Industrial Design Engineering - Haute Ecole Arc - Ingénierie

MSc HES-SO en Engineering - HES-SO Master

En cours

Encapsulation of bioactive natural compounds to reduce pesticide use in viticulture

AGP

Rôle: Co-requérant(s)

Requérant(e)s: 425 - Oenologie

Financement: HES-SO Rectorat

Description du projet : The application of plant protection products (commonly called pesticides) in agricultural production systems can cause numerous negative health and environmental effects, representing a serious risk for producers, consumers and biodiversity. A reduction of pesticide applications is therefore one of the biggest environmental and societal challenges in modern agriculture. Grapevines are highly susceptible to many pathogens, making the viticulture industry one of the biggest consumers of pesticides by occupying ~3% of arable land in Europe yet being responsible for 40% of pesticide usage. New solutions to reduce the reliance on synthetic and organic pesticides in viticulture are thus urgently needed. Natural compounds such as essential oils (EOs) and their constituents have been proven effective against fungal pathogens, as shown in a previous HES-SO funded project (EOVOC). The latter project led to the acceptance of two follow-up projects funded by the SNSF (DuraPrimVine and EpiStimGrape). These projects are still ongoing in Changins and have already produced interesting fundamental results published in international peer-reviewed journals. These projects aim to better understand the molecular mechanisms triggered in grapevines by EOs in climate chamber and leaf disc experiments. In those projects, the efficiency of EOs and their constituents against downy mildew have been demonstrated, but results remain purely fundamental and require further development. Indeed, EOs and their volatile constituents possess several drawbacks preventing them from being directly applicable in the vineyard, including hydrophobicity, bad miscibility, poor rain fastness and UV degradability. Furthermore, high concentrations of EOs cause important phytotoxic effects when applied to plants. Encapsulation offers a solution by enhancing stability and enabling controlled release, which would allow a slow and continuous delivery of the active agent at an optimal threshold. The project proposed here will be carried out in close conjunction with the current SNSF projects and will develop and test new application methods for the field application of EOs by joining the expertise of Changins and HE-Arc schools. The aim of this project is to develop and test methods to encapsulate oregano EO as well as its most bioactive compounds (carvacrol and thymol) to evaluate their applicability and antifungal effect in vivo in the field. The use of microfluidic setups by HE-Arc currently allows the production of 500 'm diameter microcapsules from a sodium alginate suspension, a biomaterial widely used for encapsulation processes. The production capacity, encapsulation yield, capsule loading, capsule stability and release profiles of active ingredients of microcapsules from the different setups will be assessed (HE-Arc) and the most promising one will be selected to produce microcapsules for experiments with grapevines. These microcapsules will then be tested by Changins in both in vitro and field trials on grapevines infected with various fungal diseases to evaluate their applicability and effectiveness against these pathogens. This interdisciplinary collaboration seeks to intertwine microtechnology and viticulture to innovate sustainable pest management strategies, offering growers environmentally friendly solutions to reduce pesticide applications in the vineyard.

Equipe de recherche au sein de la HES-SO: Feuvrier Lauryne , Farine Brunner Sophie , Kämpfer Alexandra , Cléroux Marilyn , Burdet Jean-Philippe , Rienth Markus , Wenger Samuel , Alvarez Seoane Esteban , Chappuis Charles , Laux Edith , Jeandupeux Laure , Alfonso Esteban

Partenaires académiques: 425 - Oenologie; Dispositifs médicaux

Durée du projet: 01.02.2025 - 31.07.2026

Montant global du projet: 220'000 CHF

Statut : En cours

AOP Plug and play

Rôle: Co-requérant(s)

Financement: Bridge Discovery

ComplexFluidPrint

Rôle: Co-requérant(s)

Financement: HES-SO

Terminés

Une nouvelle génération de sensors pour la détection du phosgène (PhoSensor)

Rôle: Collaborateur/trice

Financement: HES-SO

Description du projet :

Phosgene (COCl2) is a highly poisonous chemical weapon agent (CWA). Unlike other CWA whose production and use are internationally prohibited, several million tons of phosgene are produced all over the world each year because this compound is a valuable building block for the synthesis of various plastics, pesticides and pharmaceuticals. This represents a huge threat to public health and safety not only because of possible accidental leaking but also because of potential terrorist attacks. Thus, is of great importance to develop highly sensitive and selective sensors for phosgene in gas but also in liquid phase.
A number of phosgene sensors based on diamine or alcohol type sensing molecules are available but most of them have important limitations in terms of portability, selectivity, detection limit, costs and / or lifetime.
Recently, we discovered in a totally serendipitous manner, that a new compound, a carboxylic derivative of a chiral pinenepyridine compound (1 in the project description) reacts with traces of phosgene present accidentally in a sample. The resulting isoindolone type molecule is colored and luminescent. Some preliminary investigations were performed under the guidance of the internationally recognized Swiss institute for the protection of the population against nuclear, biological and chemical threats and dangers, known also as Spiez Laboratory, who provides worldwide services relating to arms control, protection measures, health and incident management. These investigations have shown very promising results: stable sensing molecule, very rapid sensing reaction, high selectivity, very low detection limit.
In the framework of this project we propose to investigate the use of a completely new sensing type reaction, never reported in literature, in order to develop a fluorescent / colorimetric portable sensor for phosgene and phosgene related products.
The chemists from HEIA will design and synthesize a library of compounds structurally related to parent compound 1. In the environmental conditions the sensor is expected to operate, these molecules will be benchmarked in terms of stability, selectivity, detection limit and cost projections. The best candidates will be selected and their synthetic route optimized.
Programme de recherche / Appel à projets 2021 2/24
The engineers from HE Arc will built up the appropriate sensor prototype as a portable device, in agreement with the requirements of the sensing system. Using their proven skills in microfluidics, microelectronics and sensors integration, they will start by encapsulating the sensing molecule in a high surface area material (made by electrospinning). Readout on the portable device will be done:
a) qualitatively by a change in color/fluorescence of the sensor fabric and
b) quantitatively by a compact optical readout made of a LED/filter/photodiode cost-effective setup.
The HES-SO consortium will work in close collaboration with the Spiez Laboratory who will test the sensing molecules (in the WP2) but also the sensor prototype (WP5) and help to establish contacts with potential interested end users from industry for commercial exploitation. Moreover, other very dangerous, phosgene related molecules to which only this specialized laboratory has access, molecules chemically compatible with the new sensing system proposed here, will be tested in Spiez.

Equipe de recherche au sein de la HES-SO: Jeandupeux Laure , Mamula Steiner Olimpia , Kämpfer Alexandra , Laux Edith

Durée du projet: 01.12.2021 - 30.06.2023

Statut : Terminé

Food quality, Antioxidant assays, HPLC, Microfluidics, MeV ion beam lithography, track and trace

AGP

Rôle: Requérant(e) principal(e)

Financement: HES-SO Rectorat

Description du projet : The project's objective is to combine both approaches into a system that for one sample injection fingerprints the bioactive compounds and assesses the antioxidant activities of individual compounds at the same time. This is done by a plug-in device that can be fitted to different HPLC instruments or stand-alone with FIA systems. The device is based on a microfluidic chip that splits the HPLC eluent stream between three anti-oxidant analysis modules operating in parallel with conventional UV/Vis fluorescence detector. Two modules will assay antiradical scavenging activity (DPPH' and ABTS'+ (TEAC assay)) and the third total antioxidant capacity (ferric reducing antioxidant power FRAP). The results enable assessment of the compounds responsible for the antioxidant capacity of analysed food sample. This knowledge helps to select the most promising marker compounds for tracing antioxidant evolution from farm to fork through the food chain.

Equipe de recherche au sein de la HES-SO: Farine Brunner Sophie , Andlauer Wilfried , Kämpfer Alexandra , Geiser Martial , Broggini Christiane , Cséfalvay Catherine , Prieur Claudio , Ramseyer Stephan , Bisoffi Fabrice , Udrisard Isabelle , Truffer Frédéric , Hochstrasser Eric , Jeandupeux Laure

Partenaires académiques: VS - Institut Systèmes industriels; VS - Institut Sciences du vivant; Micro et nano systèmes; Kämpfer-Homsy Alexandra, Micro et nano systèmes

Durée du projet: 01.12.2016 - 30.11.2018

Montant global du projet: 164'950 CHF

Statut : Terminé

Intégration d'un capteur permettant le suivi en continu de substances thérapeutiques dans le sang - Diagnostic Biochips - Projet DB-2015-003

AGP

Rôle: Co-requérant(s)

Requérant(e)s: VS - Institut Systèmes industriels, Roduit Pierre, VS - Institut Systèmes industriels

Financement: HES-SO Rectorat

Description du projet : Lors de traitements médicamenteux à l'hôpital tels que les chimiothérapies ou les anesthésies, les patients sont soumis à des doses très élevées de la substance thérapeutique pendant de longues durées qui peuvent aller jusqu'à plusieurs jours lors de cancers. Les concentrations du médicament dans le sang peuvent alors considérablement varier et atteindre des niveaux entraînant des effets secondaires importants voire fatals. Idéalement, les doses de médicament devraient être continuellement adaptées pour éviter ces pics et ainsi fortement atténuer les effets secondaires, mais ceci nécessiterait des analyses sanguines régulières (typ. tous les 5-15 minutes), ce qui n'est actuellement pas possible pour des raisons logistiques. Un système de mesure continu rendrait possible un tel suivi avec la possibilité d'éventuellement corriger le dosage de manière automatique. Dans le cadre du projet SupraDiag, des bio-senseurs supramoléculaires sont en cours de développement dont la fluorescence est modulée par la présence de substances actives de chimiothérapies. L'objectif de ce nouveau projet est d'intégrer cette technologie dans un démonstrateur permettant de faire le suivi quantitatif de médicaments directement dans le sang. Ce projet extrêmement interdisciplinaire aura pour but de régler tous les problèmes importants qu'il reste à résoudre pour avoir un démonstrateur portable: - Développement d'un système micro-fluidique pour le prélèvement et le transfert de l'échantillon vers une micro-chambre contenant les bio-senseurs et pour le lavage de celle-ci après la mesure, - Adaptation des bio-senseurs supramoléculaires aux mesures en continu dans le sang, - Insertion des bio-senseurs dans des hydrogels protecteurs permettant de ne laisser diffuser que les petites molécules, - Conception de revêtements anti-biofouling, - Développement de l'optique intégrée qui permettra de mesure le taux de fluorescence émise par les bio-senseurs, - Développement de l'électronique de contrôle et de mesure, - Développement de la partie communication sans fils qui permettra d'exporter la valeur mesurée du capteur. Ce projet pourra profiter des technologies développées dans le cadre du programme durant les projets SmartH2OGel (hydrogels), SupraDiag (bio-senseurs supramoléculaires) et MiniBioDet (modification de surfaces). L'appareil de suivi de substances thérapeutiques développé dans ce projet sera le démonstrateur prototypique d'une nouvelle génération d'instruments de médecine personnalisée.

, , , , , , , , , , , , , , , , , , Equipe de recherche au sein de la HES-SO: Walpen Olivier Aellen Thierry Farine Brunner Sophie Kämpfer Alexandra Condemi Enrico Geiser Martial Broggini Christiane Cséfalvay Catherine Prieur Claudio Truffer Frédéric Hochstrasser Eric Simalatsar Alena Marti Roger Segura Jean-Manuel Laux Edith Jeandupeux Laure Pfeifer Marc Emil Roduit Pierre Jacquemettaz Pascal

Partenaires académiques: VS - Institut Systèmes industriels; Microtechnologies appl.; VS - Institut Sciences du vivant; FR - EIA - Institut ChemTech; Roduit Pierre, VS - Institut Systèmes industriels

Durée du projet: 01.01.2016 - 31.12.2017

Montant global du projet: 250'000 CHF

Statut : Terminé

2020

Impact of organic solvents in combination with redox-couples on magnitude of seebeck coefficient, and electrical current in thermoelectric generators

Article scientifique ArODES

Edith Laux, Laure Jeandupeux, Alexandra Kämpfer, Martin Hofmann, Philippe Potty, Herbert Keppner

Materials Today: Proceedings, 2021, 44, 4, 3489-3493

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2017

Fabrication of high-transmission microporous membranes by proton beam writing-based molding technique

Article scientifique ArODES

Liping Wang, Clemens Meyer, Edouard Guibert, Alexandra Kämpfer, Harry J. Whitlow

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2017, vol. 404, pp. 224-227

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2016

Red blood cell phase separation in symmetric and asymmetric microchannel networks : effect of capillary dilation and inflow velocity

Article scientifique ArODES

Francesco Clavica, Alexandra Kämpfer, Laure Jeandupeux, Dominik Obrist

Scientific reports, 2016, article no. 36763

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2015

Fabrication and characterization of a test platform integrating nanoporous structures with biochemical functionality

Article scientifique ArODES

Karen Twomey, Paul O'Mara, Jaroslaw Pulka, Shane McGillycuddy, Eileen Hurley, Allan Blake, Patricia Vazquez, Elizaveta Vereshchagina, Mary Manning, Alexandra Kämpfer, Barry Glynn, Vladimir I. Ogurtsov

IEEE Sensors Journal, 2015, vol. 15, no. 8, pp. 4329-4337

Lien vers la publication

Résumé:

The application of solid-state nanopore technology for biosensing is a rapidly developing area of research with high commercial potential. Different synthetic materials, including silicon nitride, alumina, and polymers, are employed to fabricate single and multiple pores and offer a good platform for selective biomolecule detection. Two solid-state pore arrays, one with integrated silicon microfluidic system, were considered and an immobilization strategy suitable for detecting a single-stranded DNA (ssDNA) sequence was investigated. For the silicon nitride pores, a modification method based on the use of 3-aminopropyltriethoxysilane for silanization and 1,4-phenylene diisothiocyanate for amine crosslinking was applied to immobilize 100-nM ssDNA (amine C6) and a 100-nM limit of detection for complementary to probe ssDNA (Cy5) was estimated. The polycarbonate pores (the second type of the pore arrays) underwent surface modification based on an oxidation reduction reaction using sodium periodate and sodium borohydride and was used to immobilize 10-nM ssDNA and an estimated 100-nM limit of detection was also achieved. Linear sweep voltammetry was used to characterize the pores and a current potential profile was obtained after both immobilization of probe ssDNA and hybridization of complementary to probe ssDNA on the modified pore array surface. A decrease in current amplitude was measured after surface modification of both pore arrays, and this was attributed to the appearance of an additional layer on the pore surface reducing the pore opening and hindering the current flow. The hybridization event was also supported by contact angle measurements, where an increase in hydrophilicity was recorded at the different surface modification steps that were applied to produce the biofunctionalized nanopore. In addition, fluorescence was observed on the surfaces after hybridization, through incorporation of a CY5 fluorescent tag attached on the 5' end of the complementary to probe DNA. These results show the potential to use both silicon nitride and polycarbonate nanopores in DNA detection applications.

MeV ion beam lithography of biocompatible halogenated parylenes using aperture masks

Article scientifique ArODES

Harry J. Whitlow, Rattanaporn Norarat, Marta Roccio, Patrick Jeanneret, Edouard Guibert, Maxime Bergamin, Gianni Fiorucci, Alexandra Kämpfer, Edith Laux, Herbert Keppner, Pascal Senn

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2015, vol. 354, pp. 34-36

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Solid on liquid deposition, a review of technological solutions

Article scientifique ArODES

Alexandra Kämpfer, Edith Laux, Laure Jeandupeux, Jerome Charmet, Roland Bitterli, Chiara Botta, Yves Rebetez, Oksana Banakh, Herbert Keppner

Microelectronic Engineering, 2014, vol. 14, pp. 467-279

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Résumé:

Solid-on-liquid deposition (SOLID) techniques are of great interest to the MEMS and NEMS (Micro- and Nano Electro Mechanical Systems) community because of potential applications in biomedical engineering, on-chip liquid trapping, tunable micro-lenses, and replacements of gate oxides. However, depositing solids on liquid with subsequent hermetic sealing is difficult because liquids tend to have a lower density than solids. Furthermore, current systems seen in nature lack thermal, mechanical or chemical stability. Therefore, it is not surprising that liquids are not ubiquitous as functional layers in MEMS and NEMS. However, SOLID techniques have the potential to be harnessed and controlled for such systems because the gravitational force is negligible compared to surface tension, and therefore, the solid molecular precursors that typically condense on a liquid surface will not sediment into the fluid. In this review we summarize recent research into SOLID, where nucleation and subsequent cross-linking of solid precursors results in thin film growth on a liquid substrate. We describe a large variety of thin film deposition techniques such as thermal evaporation, sputtering, plasma enhanced chemical vapor deposition used to coat liquid substrates. Surprisingly, all attempts at deposition to date have been successful and a stable solid layer on a liquid can always be detected. However, all layers grown by non-equilibrium deposition processes showed a strong presence of wrinkles, presumably due to residual stress. In fact, the only example where no stress was observed is the deposition of parylene layers (poly-para-xylylene, PPX). Using all the experimental data analyzed to date we have been able to propose a simple model that predicts that the surface property of liquids at molecular level is influenced by cohesion forces between the liquid molecules. Finally, we conclude that the condensation of precursors from the gas phase is rather the rule and not the exception for SOLID techniques.

2014

Mid-infrared spectroscopy for gases and liquids based on quantum cascade technologies

Article scientifique ArODES

Pierre Jouy, Markus Mangold, Béla Tuzson, Lukas Emmenegger, Yu-Chin Chang, Lubos Hvozdara, Hans Peter Herzig, Philip Wägli, Alexandra Kämpfer, Nico F. de Rooij, Alexander Wirthmueller, Daniel Hofstetter, Herbert Looser, Jérôme Faist

The Analyst, 2014, vol. 139, no. 9, pp. 2039-2046

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2013

Microfluidic droplet-based liquid–liquid extraction and on-chip IR spectroscopy detection of cocaine in human saliva

Article scientifique ArODES

Philip Wägli, Yu-Chi Chang, Alexandra Kämpfer, Lubos Hvozdara, Hans Peter Herzig, Nico F. de Rooij

Analytical Chemistry, 2013, vol. 85, no. 15, pp. 7558-7565

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2022

Production and viability of encapsulated bacterial-fungal consortia for delivery in soil

Conférence ArODES

Alexandra Kämpfer, Edith Laux, Laure Jeandupeux, T. Nogueira-Matos, A. Manimala, Nina Châtelain, Claudio Prieur, Cristina Martin-Olmos, Isha Hashmi, C. Hyde, C. Ruiz, Pilar Junier, Saskia Bindschedler

Proceedings of 26th International Conference on Miniaturized Systems for Chemistry and Life Sciences, 23-27 October 2022, Hangzhou, China

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2015

Blood cell dynamics in a simple model of microvascular networks

Conférence ArODES

Francesco Clavica, Alexandra Kämpfer, Laure Jeandupeux, Herbert Keppner, Dominik Obrist

Proceedings of 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences, 25-29 October 2015, Gyeongju, South Korea

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Réalisations

PEOPLE@HES-SO
Annuaire et Répertoire des compétences

Kämpfer Alexandra

Professeur-e HES associé-e

Compétences principales

Microfabrication

Packaging

Bonding

Microfluidics

Droplet microfluidics

Microencapsulation

Micropumps

Professeur-e HES associé-e

PEOPLE@HES-SO Annuaire et Répertoire des compétences

Kämpfer Alexandra

Professeur-e HES associé-e

Compétences principales

Microfabrication

Packaging

Bonding

Microfluidics

Droplet microfluidics

Microencapsulation

Micropumps

Professeur-e HES associé-e

PEOPLE@HES-SO
Annuaire et Répertoire des compétences