Friedrich-Wilhelm-Lübke-Koog, Germany
Friedrich-Wilhelm-Lübke-Koog, Germany

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PubMed | Fast track Diagnostics Luxembourg sarl, Ministry of Health, Jimma University, Swiss Tropical and Public Health Institute and 5 more.
Type: | Journal: Studies in health technology and informatics | Year: 2016

Malaria is a life-threatening disease that caused more than 400,000 deaths in sub-Saharan Africa in 2015. Mass prevention of the disease is best achieved by vector control which heavily relies on the use of insecticides. Monitoring mosquito vector populations is an integral component of control programs and a prerequisite for effective interventions. Several individual methods are used for this task; however, there are obstacles to their uptake, as well as challenges in organizing, interpreting and communicating vector population data. The Horizon 2020 project DMC-MALVEC consortium will develop a fully integrated and automated multiplex vector-diagnostic platform (LabDisk) for characterizing mosquito populations in terms of species composition, Plasmodium infections and biochemical insecticide resistance markers. The LabDisk will be interfaced with a Disease Data Management System (DDMS), a custom made data management software which will collate and manage data from routine entomological monitoring activities providing information in a timely fashion based on user needs and in a standardized way. The ResistanceSim, a serious game, a modern ICT platform that uses interactive ways of communicating guidelines and exemplifying good practices of optimal use of interventions in the health sector will also be a key element. The use of the tool will teach operational end users the value of quality data (relevant, timely and accurate) to make informed decisions. The integrated system (LabDisk, DDMS & ResistanceSim) will be evaluated in four malaria endemic countries, representative of the vector control challenges in sub-Saharan Africa, (Cameroon, Ivory Coast, Ethiopia and Zambia), highly representative of malaria settings with different levels of endemicity and vector control challenges, to support informed decision-making in vector control and disease management.


PubMed | Askion GmbH, ClinicaGeno Ltd, University of Zürich, Erasmus Medical Center and 5 more.
Type: | Journal: Studies in health technology and informatics | Year: 2016

Global healthcare systems are struggling with the enormous burden associated with infectious diseases, as well as the incessant rise of antimicrobial resistance. In order to adequately address these issues, there is an urgent need for rapid and accurate infectious disease diagnostics. The H2020 project DIAGORAS aims at diagnosing oral and respiratory tract infections using a fully integrated, automated and user-friendly platform for physicians offices, schools, elderly care units, community settings, etc. Oral diseases (periodontitis, dental caries) will be detected via multiplexed, quantitative analysis of salivary markers (bacterial DNA and host response proteins) for early prevention and personalised monitoring. Respiratory Tract Infections will be diagnosed by means of DNA/RNA differentiation so as to identify their bacterial or viral nature. Together with antibiotic resistance screening on the same platform, a more efficient treatment management is expected at the point-of-care. At the heart of DIAGORAS lies a centrifugal microfluidic platform (LabDisk and associated processing device) integrating all components and assays for a fully automated analysis. The project involves an interface with a clinical algorithm for the comprehensive presentation of results to end-users, thereby increasing the platforms clinical utility. DIAGORAS performance will be validated at clinical settings and compared with gold standards.


Butz N.,Albert Ludwigs University of Freiburg | Taschwer A.,Hahn Schickard | Manoli Y.,Albert Ludwigs University of Freiburg | Kuhl M.,Albert Ludwigs University of Freiburg
Digest of Technical Papers - IEEE International Solid-State Circuits Conference | Year: 2016

Functional electrical stimulation (FES) is a technique that stimulates nerves by electrical charge, but carries the risk of charge accumulation, voltage pile-up, electrode corrosion and finally tissue destruction. Using biphasic stimulus current pulses, the main transferred charge is compensated by reversing the current direction. However, due to PVT variations in integrated circuits mismatch in the biphasic waveform always occurs. Charge balancing (CB) has thus become an integral part of FES to ensure safe chronic stimulation [1]. © 2016 IEEE.


Ylli K.,Hahn Schickard | Hoffmann D.,Hahn Schickard | Willmann A.,Hahn Schickard | Folkmer B.,Hahn Schickard | And 2 more authors.
Journal of Physics: Conference Series | Year: 2015

Energy Harvesting from human motion as a means of powering body-worn devices has been in the focus of research groups for several years now. This work presents a rotational inductive energy harvester that can generate a sufficient amount of energy during normal walking to power small electronic systems. Three pendulum structures and their geometrical parameters are investigated in detail through a system model and system simulations. Based on these results a prototype device is fabricated. The masses and angles between pendulum arms can be changed for the experiments. The device is tested under real-world conditions and generates an average power of up to 23.39 mW across a resistance equal to the coil resistance of the optimal pendulum configuration. A regulated power output of the total system including power management of 3.3 mW is achieved. © Published under licence by IOP Publishing Ltd.


Schwemmer F.,Albert Ludwigs University of Freiburg | Hutzenlaub T.,Hahn Schickard | Buselmeier D.,Albert Ludwigs University of Freiburg | Paust N.,Albert Ludwigs University of Freiburg | And 4 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2015

The generation of mixtures with precisely metered volumes is essential for reproducible automation of laboratory workflows. Splitting a given liquid into well-defined metered sub-volumes, the so-called aliquoting, has been frequently demonstrated on centrifugal microfluidics. However, so far no solution exists for assays that require simultaneous aliquoting of multiple, different liquids and the subsequent pairwise combination of aliquots with full fluidic separation before combination. Here, we introduce the centrifugo-pneumatic multi-liquid aliquoting designed for parallel aliquoting and pairwise combination of multiple liquids. All pumping and aliquoting steps are based on a combination of centrifugal forces and pneumatic forces. The pneumatic forces are thereby provided intrinsically by centrifugal transport of the assay liquids into dead end chambers to compress the enclosed air. As an example, we demonstrate simultaneous aliquoting of 1.) a common assay reagent into twenty 5 μl aliquots and 2.) five different sample liquids, each into four aliquots of 5 μl. Subsequently, the reagent and sample aliquots are simultaneously transported and combined into twenty collection chambers. All coefficients of variation for metered volumes were between 0.4%-1.0% for intra-run variations and 0.5%-1.2% for inter-run variations. The aliquoting structure is compatible to common assay reagents with a wide range of liquid and material properties, demonstrated here for contact angles between 20° and 60°, densities between 789 and 1855 kg m-3 and viscosities between 0.89 and 4.1 mPa s. The centrifugo-pneumatic multi-liquid aliquoting is implemented as a passive fluidic structure into a single fluidic layer. Fabrication is compatible to scalable fabrication technologies such as injection molding or thermoforming and does not require any additional fabrication steps such as hydrophilic or hydrophobic coatings or integration of active valves. © The Royal Society of Chemistry 2015.


Zhao Y.,Hahn Schickard | Schwemmer F.,Albert Ludwigs University of Freiburg | Zehnle S.,Hahn Schickard | Von Stetten F.,Hahn Schickard | And 5 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2015

Microparticles are widely used as solid phase for affinity-based separation. Here, we introduce a new method for automated handling of microparticles in centrifugal microfluidics that is not restricted by the particle size and requires neither auxiliary means such as magnets nor coating of microfluidic structures. All steps are initiated and controlled by the speed of rotation only. It is based on storage and "on demand" release of pneumatic energy within tunable time frames: a slow release of the pneumatic energy triggers a first fluidic path through which the supernatant above the sedimented particles is removed. An abrupt release triggers a second path which allows for liquid routing and transport of the re-suspended particles. Re-suspension of particles is thereby achieved by quickly changing the speed of rotation. We demonstrate the exchange of the particle carrier medium with a supernatant removal efficiency of more than 99.5% and a particle loss below 4%. Re-suspension and subsequent transport of suspended particles show a particle loss below 7%. The method targets the automation of particle-based assays e.g. DNA extractions and immunoassays. It is compatible with monolithic integration and suitable for mass production technologies e.g. thermoforming or injection moulding. © The Royal Society of Chemistry.


PubMed | Hahn Schickard and Albert Ludwigs University of Freiburg
Type: Journal Article | Journal: Lab on a chip | Year: 2016

Centrifugal microfluidics shows a clear trend towards a higher degree of integration and parallelization. This trend leads to an increase in the number and density of integrated microfluidic unit operations. The fact that all unit operations are processed by the same common spin protocol turns higher integration into higher complexity. To allow for efficient development anyhow, we introduce advanced lumped models for network simulations in centrifugal microfluidics. These models consider the interplay of centrifugal and Euler pressures, viscous dissipation, capillary pressures and pneumatic pressures. The simulations are fast and simple to set up and allow for the precise prediction of flow rates as well as switching and valving events. During development, channel and chamber geometry variations due to manufacturing tolerances can be taken into account as well as pipetting errors, variations of contact angles, compliant chamber walls and temperature variations in the processing device. As an example of considering these parameters during development, we demonstrate simulation based robustness analysis for pneumatic siphon valving in centrifugal microfluidics. Subsequently, the influence of liquid properties on pumping and valving is studied for four liquids relevant for biochemical analysis, namely, water (large surface tension), blood plasma (large contact angle hysteresis), ethanol/water (highly wetting) and glycerine/water (highly viscous). In a second example, we derive a spin protocol to attain a constant flow rate under varying pressure conditions. Both examples show excellent agreement with experimental validations.


PubMed | Hahn Schickard and Albert Ludwigs University of Freiburg
Type: Journal Article | Journal: Lab on a chip | Year: 2016

We present batch-mode mixing for centrifugal microfluidics operated at fixed rotational frequency. Gas is generated by the disk integrated decomposition of hydrogen peroxide (H2O2) to liquid water (H2O) and gaseous oxygen (O2) and inserted into a mixing chamber. There, bubbles are formed that ascent through the liquid in the artificial gravity field and lead to drag flow. Additionaly, strong buoyancy causes deformation and rupture of the gas bubbles and induces strong mixing flows in the liquids. Buoyancy driven bubble mixing is quantitatively compared to shake mode mixing, mixing by reciprocation and vortex mixing. To determine mixing efficiencies in a meaningful way, the different mixers are employed for mixing of a lysis reagent and human whole blood. Subsequently, DNA is extracted from the lysate and the amount of DNA recovered is taken as a measure for mixing efficiency. Relative to standard vortex mixing, DNA extraction based on buoyancy driven bubble mixing resulted in yields of 92 8% (100 s mixing time) and 100 8% (600 s) at 130g centrifugal acceleration. Shake mode mixing yields 96 11% and is thus equal to buoyancy driven bubble mixing. An advantage of buoyancy driven bubble mixing is that it can be operated at fixed rotational frequency, however. The additional costs of implementing buoyancy driven bubble mixing are low since both the activation liquid and the catalyst are very low cost and no external means are required in the processing device. Furthermore, buoyancy driven bubble mixing can easily be integrated in a monolithic manner and is compatible to scalable manufacturing technologies such as injection moulding or thermoforming. We consider buoyancy driven bubble mixing an excellent alternative to shake mode mixing, in particular if the processing device is not capable of providing fast changes of rotational frequency or if the low average rotational frequency is challenging for the other integrated fluidic operations.

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