Zurich Instruments AG

Zürich, Switzerland

Zurich Instruments AG

Zürich, Switzerland
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Grant
Agency: European Commission | Branch: FP7 | Program: CP | Phase: ICT-2009.3.9 | Award Amount: 3.94M | Year: 2010

Analysis of biological cells down to single cell resolution is a prospective technique in nearly all fields of life science research. In particular manipulation and analysis of single cells can open up a new dimension in cell biology, tissue engineering, drug development and diagnostics. The advancement of single cell technology as a whole requires tools and instrumentation to sort, transport and manipulate single living cells. Micro system technology with its sophistications can provide in this context capabilities far beyond todays methods.\n\nTherefore, this project aims to develop a single cell manipulator (SCM) micro instrument for inkjet like printing of single living cells confined in micro droplets of only 50m size. Such a device can serve as a universal tool for manipulating cells in a non-invasive flexible manner. Within the project the SCM device will be applied to cell biological applications in cancer research and drug development to demonstrate and validate the performance of the device, as well as to establish a flexible platform for advanced single cell-manipulation and analysis (PASCA).\n\nIn order to achieve these objectives crosscutting technological challenges have to be faced which can be overcome by integrating and interfacing multiple core technologies, only. Cutting edge bio-sensing technology like impedance spectroscopy and state of the art micro dispensing methods will be applied and combined with latest cell biological methods to establish the SCM instrument as multifunctional microsystem for cell manipulation. Through the highly innovative integrated approach and the validation within the PASCA platform the SCM instrument has excellent exploitation perspectives in multiple application sectors.\n\nAlso the project structure as a whole supports the objectives of the work program:By intensively involving SMEs to feed the innovation cycle and by bringing the user into research cycles through the open access partner structure.


Haandbaek N.,ETH Zurich | With O.,ETH Zurich | Burgel S.C.,ETH Zurich | Heer F.,Zurich Instruments AG | Hierlemann A.,ETH Zurich
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2014

This paper reports on a novel impedance-based cytometer, which can detect and characterize sub-micrometer particles and cells passing through a microfluidic channel. The cytometer incorporates a resonator, which is constructed by means of a discrete inductor in series with the measurement electrodes in the microfluidic channel. The use of a resonator increases the sensitivity of the system in comparison to state-of-the-art devices. We demonstrate the functionality and sensitivity of the cytometer by discriminating E. coli and B. subtilis from beads of similar sizes by means of the resonance-enhanced phase shift of the current through the microfluidic channel. The phase shift can be correlated to size and dielectric properties of the measured objects. © 2014 the Partner Organisations.


Haandbaek N.,ETH Zurich | Burgel S.C.,ETH Zurich | Heer F.,Zurich Instruments AG | Hierlemann A.,ETH Zurich
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2014

Single-cell impedance cytometry is an electrical analysis method, which has been used to count and discriminate cells on the basis of their dielectric properties. The method has several advantages, such as being label free and requiring minimal sample preparation. So far, however, it has been limited to measuring cell properties that are visible at low frequencies, such as size and membrane capacitance. We demonstrate a microfluidic single cell impedance cytometer capable of dielectric characterization of single cells at frequencies up to 500 MHz. This device features a more than ten-fold increased frequency range compared to other devices and enables the study of both low and high frequency dielectric properties in parallel. The increased frequency range potentially allows for characterization of subcellular features in addition to the properties that are visible at lower frequencies. The capabilities of the cytometer are demonstrated by discriminating wild-type yeast from a mutant, which differs in size and distribution of vacuoles in the intracellular fluid. This discrimination is based on the differences in dielectric properties at frequencies around 250 MHz. The results are compared to a 3D finite-element model of the microfluidic channel accommodating either a wild-type or a mutant yeast cell. The model is used to derive quantitative values to characterize the dielectric properties of the cells. This journal is © The Royal Society of Chemistry.


Grant
Agency: European Commission | Branch: FP7 | Program: CP | Phase: SME-2013-3 | Award Amount: 2.18M | Year: 2013

This DIMIDplus Demonstration Action is a direct follow-on of the DIMID (286692, FP7-SME-2011) project. The DIMID project is successful, on time, in its second year finishing in Sep 2013 and both its efficiency and its potential are proven already. The work achieved so far is promising to reach the set objectives. The mode of collaboration among the SMEs is productive. The SMEs form a strong consortium with the potential to market also a complex high-tech product like DIMID. This represents a significant value for the industrial strength of Europe. The RTDs have done and are still doing an excellent job. What remains is that the SMEs themselves invest a common effort into the last mile of commercialization, which shall be realised within this Demonstration Activity scheduled for 18 months. The DIMID project will lead to the first prototypes of low-cost impedance-based cytometer suitable for non-spherical cells. Based on these prototypes the DIMIDplus consortium aims to commercialize a portable impedance-based microfluidic cytometer equipped with disposable chips. The consortium of the DIMIDplus project consists of all formerly involved SMEs (ZURICH, CELLIX, CYTOGNOS) and is complemented by LABS64 (IT provider, specialized in software quality, verification and testing) and AMPHASYS (single-cell electrical impedance technology leader and IPR holder) to commercialize the DIMID device and the electronic unit by verifying their performance, further testing to increase reliability, checking CE conformity and product packaging.


Home > Press > Technical partnership at the top – Oxford Instruments and Zurich Instruments announce a technical collaboration for low temperature physics Abstract: Oxford Instruments (OI), market leader in cryogenic equipment, and Zurich Instruments (ZI), the technical leader for digital lock-in amplifiers, announce today their joint technical collaboration primarily focused on demonstrating how the efficiency of combining equipment from both companies results in reduced time between installation and measurement. The collaboration will yield a series of joint application notes featuring low temperature measurement techniques and applications. The two companies will also exchange technical expertise in order to improve their customer support for the low temperature community. Both companies are devoted to the objective of managing the increasing complexity and costs of low temperature research. “This collaboration continues to demonstrate the versatility of Oxford Instruments’ OptistatDry Cryofree® cryostat for optical and electrical applications. Our customers' demands for streamlined experiments and the joint demonstrations with ZI equipment provide the evidence for faster and more accurate measurements taken in less time,” said Dr Michael Cuthbert, Managing Director at Oxford Instruments Nanoscience. The OptistatDry comprises a range of compact cryostats with outstanding optical access, fast set-up and fast sample change, cooled by a closed cycle refrigerator. “Our lock-in amplifiers are designed for efficient and effective measurements. The high-end features and usability that we have developed for our instruments are now, with the MFLI lock-in amplifiers, available for low and medium frequencies”, said Sadik Hafizovic, CEO of Zurich Instruments. Covering the frequency range between DC and 500 kHz or, alternatively, up to 5 MHz, the MFLI ideally targets low temperature communities providing signal generation and measurement analysis all within its LabOne© software environment, resulting in an improved understanding of the signal quality during the course of their measurements. The first application note resulting from this collaboration has already been released. The publication relates to the characterization of a high temperature superconducting sample using the MFLI Lock-in Amplifier and the OptistatDry cryostat. Download the document from the ZI website http://www.zhinst.com/applications/appnotes and from the OI site http://www.oxford-instruments.com/businesses/nanotechnology/nanoscience/campaigns/application-note-using-optistatdry . You can also request more information at and . Issued for and on behalf of Oxford Instruments NanoScience. About Oxford Instruments NanoScience Oxford Instruments NanoScience designs, supplies and supports market-leading research tools that enable quantum technologies, new materials and device development in the physical sciences. Our tools support research down to the atomic scale through creation of high performance, cryogen free low temperature and magnetic environments, based upon our core technologies in low and ultra-low temperatures, high magnetic fields and system integration, with ever-increasing levels of experimental and measurement readiness. Oxford Instruments NanoScience is a part of the Oxford Instruments plc group. About Oxford Instruments plc Oxford Instruments designs, supplies and supports high-technology tools and systems with a focus on research and industrial applications. Innovation has been the driving force behind Oxford Instruments' growth and success for over 50 years, and its strategy is to effect the successful commercialisation of these ideas by bringing them to market in a timely and customer-focused fashion. The first technology business to be spun out from Oxford University, Oxford Instruments is now a global company and is listed on the London Stock Exchange (OXIG). Its objective is to be the leading provider of new generation tools and systems for the research and industrial sectors with a focus on nanotechnology. Its key market sectors include nano-fabrication and nano-materials. The company’s strategy is to expand the business into the life sciences arena, where nanotechnology and biotechnology intersect This involves the combination of core technologies in areas such as low temperature, high magnetic field and ultra high vacuum environments; Nuclear Magnetic Resonance; X-ray, electron, laser and optical based metrology; atomic force microscopy; optical imaging; advanced growth, deposition and etching. Oxford Instruments aims to pursue responsible development and deeper understanding of our world through science and technology. Its products, expertise, and ideas address global issues such as energy, environment, security and health. About Zurich Instruments Zurich Instruments makes lock-in amplifiers, phase-locked loops, and impedance spectroscopes that have revolutionized instrumentation in the medium-frequency (MF) up to the ultra-high-frequency (UHF) ranges by combining frequency-domain tools and time-domain tools within each product. This reduces the complexity of laboratory setups, removes sources of problems and provides new measurement approaches that support the progress of research. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


Home > Press > Oxford Instruments announces the launch of the SampleProtect measurement system for sensitive samples used in spectroscopy experiments Abstract: Oxford Instruments is pleased to announce the launch of the unique SampleProtect measurement system. It is ideal for ESD protection and is optimised for opto-electrical measurement experiments, ensuring sensitive samples are protected throughout the whole experiment. It also minimises the time taken to obtain first experimental results. The SampleProtect measurement system comes complete with Oxford Instruments’ Cryofree® bottom loading cryostat – the OptistatDry BLV, MFLI Lock-in Amplifier from Zurich Instruments, a specially designed ESD break-out box and high quality cables. The SampleProtect measurement system ensures that the user’s sample is protected from the risk of electrostatic discharge (ESD) damage from the moment it is electrically connected to the patent pending pucks. ESD protection is designed into the system at every stage of the experiment. This means every time you load a sample into the cryostat you can be confident that it is electrically protected – no more waiting until the sample is cold to find out whether it has been damaged during the loading process. SampleProtect provides fully earthed signal management, eliminating the risk of earth loops that might interfere with your signal. Full measurement quality interconnecting cables for your low level signals are also provided. The Cryofree® OptistatDry BLV model allows samples to be cooled to less than 3 K without the need for liquid cryogens. It has been designed with customers’ experiments in mind, making integration into spectroscopy experiments quick and easy. Sample change is done through the unique load port with the cryostat in-situ, eliminating the need for removal and re-aligning of the cryostat for each and every sample change. This minimises the time taken from setting up the new cryostat to obtaining the first experimental results, and in between subsequent experiments. The MFLI Lock-in Amplifier provides superior performance in the low and medium frequency domain and is paired with the outstanding functionality of the LabOne® measurement toolset. Additionally, the differential voltage and current inputs of the MFLI are optimised for low noise operation. The high oversampling rate ensures an even better signal-to-noise ratio, which is essential for low temperature applications. Users can characterise their samples with a multitude of analysis tools like the oscilloscope, the spectrum analyser, the SW trigger or the parametric sweeper, all within the same user interface, which reduces complexity. The MFLI integrated with the OptistatDry BLV model comes equipped with 500 kHz frequency range and 4 demodulators for measurements at 4 frequencies simultaneously. “The SampleProtect measurement capability brings the advantages of the OptistatDry family to opto-electrical measurements. ESD damage to samples is a major issue for researchers with sensitive samples, such as those working on quantum devices. This unique system ensures that the sample is protected at every stage of the experiment making these types of measurements much more efficient”, said David Clapton, Product Lifecycle Manager at Oxford Instruments NanoScience. Issued for and on behalf of Oxford Instruments NanoScience About Oxford Instruments NanoScience Oxford Instruments NanoScience designs, supplies and supports market-leading research tools that enable quantum technologies, new materials and device development in the physical sciences. Our tools support research down to the atomic scale through creation of high performance, cryogen free low temperature and magnetic environments, based upon our core technologies in low and ultra low temperatures, high magnetic fields and system integration, with ever-increasing levels of experimental and measurement readiness. Oxford Instruments NanoScience is a part of the Oxford Instruments plc group. About Oxford Instruments plc Oxford Instruments designs, supplies and supports high-technology tools and systems with a focus on research and industrial applications. Innovation has been the driving force behind Oxford Instruments' growth and success for over 50 years, and its strategy is to effect the successful commercialisation of these ideas by bringing them to market in a timely and customer-focused fashion. The first technology business to be spun out from Oxford University, Oxford Instruments is now a global company and is listed on the London Stock Exchange (OXIG). Its objective is to be the leading provider of new generation tools and systems for the research and industrial sectors with a focus on nanotechnology. Its key market sectors include nano-fabrication and nano-materials. The company’s strategy is to expand the business into the life sciences arena, where nanotechnology and biotechnology intersect This involves the combination of core technologies in areas such as low temperature, high magnetic field and ultra high vacuum environments; Nuclear Magnetic Resonance; X-ray, electron, laser and optical based metrology; atomic force microscopy; optical imaging; advanced growth, deposition and etching. Oxford Instruments aims to pursue responsible development and deeper understanding of our world through science and technology. Its products, expertise, and ideas address global issues such as energy, environment, security and health. About Zurich Instruments Zurich Instruments makes lock-in amplifiers, phase-locked loops, and impedance analyzers that have revolutionized instrumentation in the medium-frequency (MF) to ultra-high-frequency (UHF) ranges by combining frequency-domain tools and time-domain tools within each product. This reduces the complexity of laboratory setups, removes sources of problems and provides new measurement approaches that support the progress of material research. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | September 21, 2016
Site: www.nature.com

The space bandwidth product of the hologram (h) is SW  = N × N = (L/d)2, where L and d are the lateral sizes of the hologram and each pixel, respectively, and N is the number of pixels in each dimension. On the other hand, the space bandwidth product of the image (i) is SW  = L2B2 where B is the spatial bandwidth of the image13. Free space propagation cannot increase the space bandwidth product, so SW  ≤ SW . But the upper bound of the image’s spatial bandwidth is set by the diffraction limit, ~λ/2, so that , and . Diffraction-limited performance is achieved when SW  = SW , which reduces to d = λ/2. Because the hologram information is stored mostly in its phase profile (transmission losses α (x,y) are low) it is critical to use the exact phase term for propagating the wave during iteration. We use the angular spectrum method31, as it performs well, yields the exact phase and has low computational cost. The acoustic pressure wave is expressed as where the explicit time dependence has been dropped, and where and are the amplitude and phase function maps, respectively. The angular spectrum of this wave in a plane at constant z is obtained by the Fourier transform: We define z = 0 to be the hologram plane. Once P(k , k , 0) is known, the angular spectrum at any plane downstream can be calculated by multiplying the angular spectrum with a propagator function where k  = |k| = ω/c is the wavenumber in the liquid medium, ω the angular frequency, c the speed of sound in the medium, and the wave vector k = (k , k , k ). The real-space pressure field in any plane z can be obtained via the inverse Fourier transform: Backpropagation from the image to the hologram can be calculated with The limited size of the observation window leads to a cut-off of higher spatial frequencies over the propagation distance. We therefore limit the integration region of the inverse Fourier transform to account for the cut-offs32. A simple geometrical estimate yields where λ is the wavelength in the medium, and L , L are the side lengths of the observation windows in the hologram and image planes, respectively. The computational domain is limited in space, which has the effect that over large propagation distances higher spatial frequencies will be reflected at the domain boundaries (aliasing). Subsequent back-propagation and multiple iterations (as required by the IASA) will push these erroneous components towards the area of interest. We therefore extend the computational domain to allow all bandwidth-limited spectral components emanating from the hologram or image aperture to propagate without aliasing. This leads to a domain size of L  ≥ 3 × max{L , L }. The field outside the hologram aperture is then set to zero. To compute the hologram we use the iterative angular spectrum approach (IASA)16. The underlying angular spectrum method keeps the exact phase term for the propagation and performs well in the nearfield at low computational cost31, 32. The phase distribution of a hologram is computed by propagating a wave from the image plane to the hologram plane and back, which is then repeated and iteratively optimized. In each iteration we adjust the complex values of the field in the hologram plane and the image plane to the desired constraints. After a few tens of iteration cycles the algorithm converges to a phase map in the plane of the holographic element. The IASA can be extended to encode multiple images in one hologram. Since the radiation force on a spherical particle in an arbitrary acoustic travelling wave can be calculated from its angular spectrum25, these calculations also serve as a basis for estimating radiation forces. We start by defining the constraints for each plane of interest. In the hologram plane the amplitude is set to the transducer output pressure distribution, , which we have measured close to the transducer and numerically back-propagated to the transducer face. We assume a flat phase output of the transducer and set the hologram phase initially to zero. The constraints (boundary conditions) for each image plane are set separately. For the example provided in Extended Data Fig. 8, the boundary conditions are the pressure distribution for each image with no constraints on the phase. If instead a phase gradient is sought, as in Fig. 3, the boundary condition is the phase distribution and is defined as a second map located in the same plane, with no constraints on the amplitude. The following steps are repeated until a satisfying image quality is obtained (in step 2). Typically, 20 to 50 iterations are required for the holograms of this paper. See Extended Data Fig. 8 for a schematic illustration. The steps for producing amplitude (phase) images are those of ref. 16 with extensions to multiple image planes and phase constraints: (1) Propagate the field from the hologram to each image plane. (2) Evaluate the quality of the projected image for each image plane. (3) Reset the amplitude (phase) for each image plane to match the target value. The forward-propagated phase (amplitude) is retained. (4) Separately propagate the field for each image plane back to the hologram. (5) Sum all back-propagated complex fields in the hologram plane. (6) Compute the thickness of the hologram pixels using equation (8), and the transmission coefficient α (x,y) using equation (7). (7) Set the complex amplitude at the hologram plane to . For simplicity we assume that the hologram is a thin element and therefore treat each pixel as a one-dimensional transmission line. The transmission coefficient relates the input power to the output power for each pixel. Z  = ρ c is the acoustic impedance, ρ the density, c the speed of sound of layer i and the subscripts t, h, m denote materials for the transducer face, hologram and medium, respectively. The acoustic properties of the cell used to contain the particles in Fig. 2a are not included in the calculation. Using the final phase map and equation (8) we compute the final thickness map T(x, y). This matrix is then converted to a mesh in the Standard Tessellation Language (STL) format, which serves as input to the 3D printer. The IASA output provides a phase map for the holographic element, which we then translate to a surface map for fabrication. The hologram plate begins with an initial thickness T . Removing material at pixel position (x, y) leads to a relative phase change where T(x, y) = T − ΔT(x, y) is the thickness of the pixel positioned at coordinates (x, y) in the hologram plane and k , k are the wave numbers in the hologram body and its surrounding medium, respectively. The resulting thickness map is then printed with a 3D printer (Objet Connex 260, Stratasys) in VeroClear material. At 2 MHz we measured the speed of sound and the sound attenuation in this material to be 2,424 m s−1 and 5.5 dB cm−1, respectively. The measurement is based on analysing the time of flight and amplitude of ultrasonic pulses through solid blocks of differing side lengths. Reflection holograms are computed in a manner similar to what was used for the in-water transmission holograms. In this case, the transducer output is first propagated to the hologram plane opposite to establish the input field across the hologram aperture. Then the hologram solution is found using the same IASA procedure. If the target region lies between transducer and hologram, the transducer output has to be separately propagated to the target plane and added to the reflected field in each iteration. We use only three waves in our cavity calculation: the initial transducer output, the hologram reflection, and that reflected in turn from the transducer face. Thus we are assuming an inefficient cavity with very low quality factor. The strong acoustic mismatch between air and the polymer hologram means that the first reflection is very efficient. The phase and thickness for a reflection hologram are related as To assess the 3D-print quality of the hologram, X-ray computed tomography (CT) was performed using a TomoScope HV 500 (Werth GmbH, Germany) with a voxel size of 81 μm × 81 μm × 81 μm. The results are shown in Extended Data Fig. 1. Extended Data Fig. 1a–c shows the designed thickness map before printing, the measured thickness map from the CT analysis, and the difference of the two, respectively. Extended Data Fig. 1d–f shows plots of the designed and measured surface profile along different horizontal slices through the sample. The desired thickness map and the achieved 3D-printed hologram are in excellent agreement, although the printing process behaves like a low-pass filter, smoothing out sharp edges and fine features. For comparison with dimensions along the x-axis, the wavelength λ is indicated in Extended Data Fig. 1d. Importantly, the CT scan shows a homogeneous density throughout the hologram except at two regions that are marked by red circles in Extended Data Fig. 1b. This is probably due to incomplete curing of the print material in the crevices near the object edges. We calculate the radiation force acting on an elastic sphere subjected to a travelling plane wave using the method developed in ref. 27, with some corrections that we made and have documented in the next section. Extended Data Fig. 6a shows the radiation force acting on a spherical particle of polydimethylsiloxane (PDMS) as a function of the particle radius for a 2 MHz incident plane wave with a 100 kPa amplitude. There are sharp resonances at discrete sizes and the general trend is for larger particles to feel stronger forces, but particles of all diameters experience a force of the same sign. To calculate the force experienced by particles that are subjected to a more complicated sound field, we follow the work of Sapozhnikov et al.25 and calculate the radiation force directly from the angular spectrum of the measured field. The angular spectrum decomposes the field into elementary plane waves propagating in different directions. We already know the scattering field for an elementary plane wave. The total scattered field resulting from the arbitrary incident field is the sum of all elementary solutions and the radiation force can then be found by integration. We start by measuring the acoustic pressure amplitude in the trapping plane. To minimize heating effects over the long (5 h) hydrophone scan, we make the measurement with the transducer driven at low power. We checked for linearity of the transducer and scaled the measured pressure field by a factor of 2.5 to match the higher power conditions used in the trapping experiment. The scaled pressure field is shown in Extended Data Fig. 6b and used as input for the following calculations. Using equation (2), we then calculate the angular spectrum of the field, and the resulting forces using the method in ref. 25. The radiation force is always calculated for a scatterer located at the origin. Therefore, to compute the forces over an area, we need to shift the angular spectrum accordingly. Example force maps are shown for different detailed sections in Extended Data Figs 6c and 7a,b along with the corresponding detail views of assembled particles during the operation of the trap. Extended Data Fig. 6e shows the trapping forces along a specific slice for particles of different sizes. In preparing this work we found two typographical errors in ref. 27 and therefore reprint corrected versions of that work’s equations (5) and (6) here. For ease of comparison, we keep the original notation: please refer to ref. 27 for definitions. In equation (6) of ref. 27, the leading minus sign in βm should be removed such that the parameters are: In addition, the factor 2 in the first term of the denominator of the compound fraction in Φ in equation (5) of ref. 27 should be removed, to yield: In their corrected form, both equations reproduce the results of the same work and other texts, as well as our experimental results. The experimental set-up consists of an open-topped glass tank (300 mm × 300 mm × 600 mm) that is partially lined with acoustic absorber sheets (Aptflex F48, Precision Acoustics Ltd, UK) and filled with deionized water (see Extended Data Fig. 9). The piezo transducer is a disk of PZT-5A with a diameter of 50 mm and a thickness of 1 mm, which is fixed to a thin brass plate and mounted in a watertight case so that the back side of the transducer is open to air. A thin layer of vacuum grease (Dow Corning) between the brass plate and the hologram provides good acoustic coupling and temporary mechanical fixing. A function generator (33120A, Hewlett-Packard) provides the reference signal and a low impedance amplifier directly drives the piezo element via coaxial cables. The operating frequency is 2.06 MHz, near the first thickness resonance of the piezo element. We used two techniques to measure the sound pressure in the working space. Quantitative, phase sensitive measurements were made using a calibrated needle hydrophone (545 mV MPa−1, 0.5 mm tip diameter, Precision Acoustics Ltd, UK) mounted on a 3D scanning gantry (GAMPT mbH, Germany). The hydrophone amplifier is connected to a lock-in amplifier (UHFLI, Zurich Instruments, Switzerland) referenced to the function generator. A script controls all the instruments and directs scans of the acoustic field in 2D and 3D. The second, qualitative measurement technique used thermochromic films. These undergo a local phase change due to acoustic heating, which results in a visible colour change. The qualitative pressure images acquired with this technique can be seen in Extended Data Fig. 3. For the particle trapping experiment a cuvette is immersed inside the tank. It is made from a 60 mm diameter acrylic tube, which is cut to 20 mm length. Both ends are covered by a 100  μm thin acoustic window made from polyethylene. The power transmission coefficient is estimated to be 90% for each window using the common 1D transmission line model for a normal incident wave. For the levitation experiments in air, the same electronics package described above was used to drive a Multicomp MCUSD40 transducer at 100 kHz. The transducer housing’s external diameter is 40 mm, but the piezo’s diameter is only 20 mm. The transducer was placed opposite a reflection hologram with an air gap of 25.7 mm between them. The hologram diameter was 40 mm. Experiments were conducted with the cavity oriented vertically (the transducer at either the top or bottom) or horizontally. Trapping lifetimes were around 30 s, limited by the thermal stability and resonance drift of the transducer. We fabricated microparticles of polydimethylsiloxane (PDMS, Sylgard 184, Dow Corning) according to procedure in ref. 24. PDMS base and curing agent were mixed at a ratio of 10:1 and added to a water bath with 1 w% non-ionic surfactant. The emulsion was continuously agitated using a high-speed emulsifier (Turaxx, IKA) while it cured overnight. A microscope image of the suspension can be seen in Extended Data Fig. 6f. The PDMS particles are polydisperse with sizes up to 400 μm diameter. The particles have a density of 1,045 kg m−3, speed of sound of 1,020 m s−1 (ref. 33), and bulk modulus of 1.1 GPa. Since they are more compressible than water the PDMS particles are attracted to pressure maxima. The acoustic surfers are elastomeric spherical caps with diameters between 2 and 4 mm and thicknesses ranging from 0.5 to 1 mm. The in-air multi-trap holographic cavity was used to capture particles of glass microballoons (3M K20, <100 μm, ρ = 0.2 g ml−1), expanded polystyrene beads (1–3 mm), softwood, lithium metal, polypropylene, silicon, and aluminium (ρ = 2.7 g ml−1). The glass microballoons and expanded polystyrene were used as supplied, the other materials were cut into irregular polyhedra with sizes from 0.7 to 2.0 mm. Droplets of isopropyl alcohol and water were also successfully trapped. See Extended Data Fig. 5 for example results. The droplets were loaded by either microsyringe injection directly into selected traps (Fig. 4b), or by aerosolization at the transducer face and coalescence of the resulting mist into multiple traps within the standing wave (Extended Data Fig. 5g–i).


Kawai S.,University of Basel | Hafizovic S.,Zurich Instruments AG | Glatzel T.,University of Basel | Baratoff A.,University of Basel | Meyer E.,University of Basel
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We propose and discuss a rapid reconstruction procedure for strongly nonlinear signals and validate it for dynamic force microscopy. Harmonics of the cantilever resonance frequency shift, generated by a low-frequency modulation of the tip-sample distance, are detected by a phase-locked loop followed by 12 lock-in amplifiers. The distance dependence of the frequency shift can be reconstructed by summing up the sampled Fourier components with judiciously assigned phase shifts. Following a successful test with a model potential, we report a measurement of the frequency shifts induced by the force field above a KBr(001) surface at room temperature in ultrahigh vacuum. Experimental spectra justify the neglect of harmonics beyond tenth order in the range where clear atomic-scale contrast appears in images of the lower harmonic intensities. A high-resolution three-dimensional frequency shift dataset was measured in 400s. The method can in general be applied to any single-valued physical quantity with a smooth nonlinear dependence on a control variable. © 2012 American Physical Society.


Grant
Agency: European Commission | Branch: FP7 | Program: BSG-SME | Phase: SME-2011-1 | Award Amount: 1.39M | Year: 2011

Cell analysis has become an important technique and represents a fast growing market for a wealth of applications in the fields of life sciences, medicine, food and environmental analytics. While clinical (diagnostic) and research applications in the healthcare and drug discovery markets demand rather complex analyses at the single cell level, routine and quality control applications in food analytics and bioprocess monitoring require simpler, quick and cheap analyses, which work more at the cell population level and provide only low-content average values instead of high-content single cell data. Many routine and quality control applications, however, would enormously profit from a higher information content of the analysis and make various processes at research and production levels more effective. This will lead to the first low-cost, portable impedance-based microfluidic cytometer equipped with disposable chips, which will enable a range of new analyses and diagnostic approaches that can be performed simply and quickly, without the use of a centralised resource. The system will rely upon the availability of highly accurate and specific disposable microfluidic chips, an high speed electronic control unit and a signal processing software which will allow to timely and accurately retrieve multiparametric information on the analysed sample.


PubMed | Zurich Instruments AG
Type: Journal Article | Journal: Biomicrofluidics | Year: 2015

Label-free isolation of single cells is essential for the growing field of single-cell analysis. Here, we present a device which prints single living cells encapsulated in free-flying picoliter droplets. It combines inkjet printing and impedance flow cytometry. Droplet volume can be controlled in the range of 500 pl-800 pl by piezo actuator displacement. Two sets of parallel facing electrodes in a 50m 55m channel are applied to measure the presence and velocity of a single cell in real-time. Polystyrene beads with <5% variation in diameter generated signal variations of 12%-17% coefficients of variation. Single bead efficiency (i.e., printing events with single beads vs. total number of printing events) was 73%11% at a throughput of approximately 9 events/min. Viability of printed HeLa cells and human primary fibroblasts was demonstrated by culturing cells for at least eight days.

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