Hradetzky, David
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Hradetzky, David
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- PublikationExperience with a continuous education program for clinical. regulatory and quality affairs in Northwestern Switzerland(IEEE EMBC, 07/2022) Etter, Philippe; Lucano, Elena; Hradetzky, David [in: 44th Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC)]04B - Beitrag Konferenzschrift
- PublikationRapid prototyping method for 3D printed biomaterial constructs with vascular structures(IEEE, 2018) Gullo, Maurizio; Köser, Joachim; Ruckli, Oliver; Eigenmann, Andrej; Hradetzky, David [in: 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)]This paper presents a fabrication method for rapid prototyping of 3D biomaterial constructs with vascular structures. The method relies on poloxamer fugitive ink, which is over casted with a custom-made alginate based model extracellular matrix (ECM). The presented method is simple to implement and compatible with standard cell culture workflows used in biomedical research and pharmaceutical development. We present the material preparation, gelation properties and printing methods in detail. First experiments demonstrate the suitability of the ECM constructs for 3D tissue culture.04B - Beitrag Konferenzschrift
- PublikationMethod for analysis of electrospray for gene transfer and the impact on cell viability of A549 alveolar epithelial like cells(IEEE, 2018) Hradetzky, David; Boehringer, Stephan; Ruzgys, Paulius; Šatkauskas, Saulius; Geiser, Thomas; Gazdhar, Amiq [in: 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)]Electrospray is a process based on creation and acceleration of small sized droplets based on electrostatic repulsion. Spraying plasmid containing liquids this process may be used to transfer genes into cells. Within this paper we report on a method for accessing and evaluating the spray modalities using high speed imaging system with a post processing of image data to obtain estimated volume and velocity of emerging droplets first. Second we investigate on the impact of different media on the spray modalities. Third we evaluate the impact of the spray on cell viability and on transfection efficiency of an eGFP plasmid as reporter gene obtained in an in vitro setup on alveolar epithelial like cells (A549).04B - Beitrag Konferenzschrift
- PublikationElectrospray application for enchanced delivery of anticancer drugs into cells(Vytautas Magnus university, 2018) Ruzgys, Paulius; Boehringer, Stephan; Tamò, Luca; Šatkauskas, Saulius; Geiser, Thomas; Gazdhar, Amiq; Hradetzky, David [in: The vital nature sign. 12th international scientific conference, May 17-18, 2018, Kaunas, Lithuania. Abstract book.]Electrospray is a process based on applied high electric voltage on liquid, leading to the creation and acceleration of small sized droplets. Electrosprayed suspension with exogenous molecules on cells can trigger intracellular delivery. Here, the application study of anticancer drug delivery via electrospray as an antitumor treatment is presented in vitro and in vivo. In vitro experiments were performed on alveolar epithelial cells (A549). Cell viability was performed with flow cytometry assay. Apoptosis/ necrosis was measured using annexin V/PI kit. In vivo experiments were done with C57BL/6J mice. Lewis lung carcinoma (LLC) cell lines were injected intradermally to induce tumor. Electrospray was performed on tumor by cutting the skin. Tumor size was measured with caliper. Results show triggered PI transfer to cells after electrospray process. Moreover, obtained results in vitro showed successful cisplatin and methotrexate intracellular delivery, resulting in around 90 % of cell viability loss with methotrexate and 70 % of cell viability loss with cisplatin. In vivo experiments reveled a tumor decrease by around 2.5 times in 7 days after electrospray treatment at first and third day with both anticancer drugs. Here we show that electrospray method can be applied to local anticancer drug delivery to cells and tissues. Therefore, such method might be adapted as a clinical anticancer therapy in the future.04B - Beitrag Konferenzschrift
- PublikationAn approach towards bronchoscopic-based gene therapy using electrical field accelerated plasmid droplets(IEEE, 2012) Hradetzky, David; Boehringer, Stephan; Geiser, Thomas; Gazdhar, Amiq [in: 2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society]Idiopathic pulmonary fibrosis (IPF) is a devastating disease affecting the distal lung, due to failure of the alveolar epithelium to heal after micro-injuries, leading to inefficient gas exchange and resulting in death. Therapeutic options are very limited. A new therapeutic approach based on gene therapy restores the self-healing process within the lung in the experimental setup. A basic requirement of this therapy is the successful transduction of genes into the alveolar epithelium in the distal part of the lung, for which a new therapeutic instrument is required. In this paper we present the concept and first experimental results of a device which uses an electrical field to accelerate the charged droplets of plasmid suspension toward the tissue and which overcomes cell membrane with its impact energy. The aim is to develop a therapeutic device capable of being integrated into minimally invasive procedures such as bronchoscopy.04B - Beitrag Konferenzschrift
- PublikationCapacitive on-line hematocrit sensor design based on impedance spectroscopy for use in hemodialysis machines(IEEE, 2009) Trebbels, D.; Hradetzky, David; Zengerle, R. [in: 2009 annual international conference of the IEEE engineering in medicine and biology society]This paper presents a new design for an on-line and in-line hematocrit (HCT) sensor. Special feature of the sensor is the capability to measure the hematocrit of a blood sample inside standard plastic tubing widely used in medical equipment. No blood sample has to be extracted out of existing extracorporeal blood circulation systems such as hemodialysis machines or heart-lung machines. The sensor principle is based on electrical impedance spectroscopy. Dielectric properties of the blood and the plastic tubing are measured at various frequencies. In order to optimize the sensitivity, a unique electrode configuration is developed and optimized by Finite Element Simulation. The new electrode design optimizes the overall sensitivity of the sensor towards a change in dielectric properties of the blood caused by the HCT value and therefore decreases the sensitivity to side effects caused by temperature drift and component tolerances. As a result of the optimized overall sensor performance the complexity of a sensor readout circuitry can be reduced to a minimum which leads to an unmatched price-performance ratio for a complete measurement system.04B - Beitrag Konferenzschrift
- PublikationHematocrit measurement - a high precision on-line measurement system based on impedance spectroscopy for use in hemodialysis machines(2009) Trebbels, Dennis; Zengerle, Roland; Hradetzky, David [in: IFMBE Proceedings]This paper presents a unique technical approach to measure the proportion of blood volume occupied by red blood cells, the hematocrit value (HCT) on-line and in-line. A practical method has been developed to measure without the need for extracting blood samples out of an existing extracorporeal blood circulation system. The new sensor is based on Impedance Spectroscopy and measures electrical properties of the blood at various frequencies. In order to achieve the required precision resolution the sensor geometry has been optimized by Finite Element Analysis. For sensor readout a digital measurement circuitry based on cheap standard components is developed and allows practical implementation of HCT-sensor devices for the first time. Special care has been taken in order to compensate for the temperature effects.04B - Beitrag Konferenzschrift
- PublikationEye-Cam: Sprachgesteuerte Miniaturkamera integriert in einer Brille(2007) Hradetzky, David; Kliche, Kurt; Ehrbrecht, Bernd; Anka, Laszlo; Wölfle, Matthias; Zengerle, Roland [in: VDE: Proceedings]04B - Beitrag Konferenzschrift
- PublikationLabel free detection of biomolecular interactions(IEEE, 2005) Hradetzky, David; Müller, Claas; Reinecke, Holger [in: IEEE/LEOS International Conference on Optical MEMS and Their Applications Conference, 2005.]This work presents a simple evanescent wave sensing system based on an interferometric approach suitable to meet the demands on label free sensor systems for the detection of biomolecular interactions especially. It is representing a basic concept towards high throughput application. The system performance and reproducibility was evaluated with refractometric measurements of sucrose dilutions. A mean resolution of the effective refractive index of 3sigma(Deltamacrnmacr eff )=0.9middot10 -6 without averaging and a reproducibility below sigma r =0.1middot10 -6 were achieved. The suitability for the detection of biomolecular interactions was validated with the detection of a DNA hybridization04B - Beitrag Konferenzschrift
- PublikationInterferometric sensor platform for biomolecular interaction analysis(VDE, 2005) Hradetzky, David; Müller, Claas; Reinecke, Holger [in: Mikrosystemtechnik-Kongress 2005]04B - Beitrag Konferenzschrift