151 research outputs found

    Genomic selection and sequencing using encoded microcarriers

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    The present invention relates to a method for determining the sequence of a nucleic molecule. Herein a capture oligonucleotide probe is attached to an encoded microcarrier, wherein the code of said microcarrier identifies the sequence of said oligonucleotide probe. The capture oligonucleotide probe is hybridized with a sample comprising nucleic acids molecules, wherein said DNA fragment comprises a sequence which is complementary to the sequence of the capture oligonucleotide probe. The sequence of the DNA molecule is determined, wherein the capture oligonucleotide probe serves as a primer for a DNA polymerase, in the case of single molecule sequencing this is a sequencing primer. After the sequence determination, the nucleotide sequence of the capture oligonucleotide probe is identified by determining the code on the microcarrier, which corresponds with the capture oligonucleotide probe. This sequence information directly identifies the location of the sequenced DNA fragment on the genome, allowing direct comparison

    Removal of Microparticles by Ciliated Surfaces-an Experimental Study

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    Biological cilia are versatile hair‐like organelles that are very efficient in manipulating particles for, e.g., feeding, antifouling, and cell transport. Inspired by the versatility of cilia, this paper experimentally demonstrates active particle‐removal by self‐cleaning surfaces that are fully or partially covered with micromolded magnetic artificial cilia (MAC). Actuated by a rotating magnet, the MAC can perform a tilted conical motion, which leads to the removal of spherical particles of different sizes in water, as well as irregular‐shaped sand grains both in water and in air. These findings can contribute to the development of novel particulate manipulation and self‐cleaning/antifouling surfaces, which can be applied, e.g., to prevent fouling of (bio)sensors in lab‐on‐a‐chip devices, and to prevent biofouling of submerged surfaces such as marine sensors and water quality analyzers

    Climbing droplets driven by mechanowetting on transverse waves

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    Many applications in modern technology, such as self-cleaning surfaces and digital microfluidics, require control over individual fluid droplets on flat surfaces. Existing techniques may suffer from side effects resulting from high electric fields and high temperatures. Here, we introduce a markedly different method, termed "mechanowetting," that is based on the surface tension-controlled droplet motion on deforming surfaces. The method is demonstrated by transporting droplets using transverse surface waves on horizontal and (vertically) inclined surfaces at transport velocities equal to the wave speed. We fully capture the fundamental mechanism of the mechanowetting force numerically and theoretically and establish its dependence on the fluid properties, surface energy, and wave parameters. Mechanowetting has the potential to lead to a range of new applications that feature droplet control through dynamic surface deformations.</p

    Single Hydrogel Particle Mechanics and Dynamics Studied by Combining Capillary Micromechanics with Osmotic Compression

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    Hydrogels can exhibit a remarkably complex response to external stimuli and show rich mechanical behavior. Previous studies of the mechanics of hydrogel particles have generally focused on their static, rather than dynamic, response, as traditional methods for measuring single particle response at the microscopic scale cannot readily measure time-dependent mechanics. Here, we study both the static and the time-dependent response of a single batch of polyacrylamide (PAAm) particles by combining direct contact forces, applied by using Capillary Micromechanics, a method where particles are deformed in a tapered capillary, and osmotic forces are applied by a high molecular weight dextran solution. We found higher values of the static compressive and shear elastic moduli for particles exposed to dextran, as compared to water (KDex≈63 kPa vs. Kwater≈36 kPa, and GDex≈16 kPa vs. Gwater≈7 kPa), which we accounted for, theoretically, as being the result of the increased internal polymer concentration. For the dynamic response, we observed surprising behavior, not readily explained by poroelastic theories. The particles exposed to dextran solutions deformed more slowly under applied external forces than did those suspended in water (τDex≈90 s vs. τwater≈15 s). The theoretical expectation was the opposite. However, we could account for this behaviour by considering the diffusion of dextran molecules in the surrounding solution, which we found to dominate the compression dynamics of our hydrogel particles suspended in dextran solutions.</p

    An artificial aquatic polyp that wirelessly attracts, grasps, and releases objects

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    The development of light-responsive materials has captured scientific attention and advanced the development of wirelessly driven terrestrial soft robots. Marine organisms trigger inspiration to expand the paradigm of untethered soft robotics into aqueous environments. However, this expansion toward aquatic soft robots is hampered by the slow response of most light-driven polymers to low light intensities and by the lack of controlled multishape deformations. Herein, we present a surface-anchored artificial aquatic coral polyp composed of a magnetically driven stem and a light-driven gripper. Through magnetically driven motion, the polyp induces stirring and attracts suspended targets. The light-responsive gripper is sensitive to low light intensities and has programmable states and rapid and highly controlled actuation, allowing the polyp to capture or release targets on demand. The artificial polyp demonstrates that assemblies of stimuli-responsive materials in water utilizing coordinated motion can perform tasks not possible for single-component devices. [Abstract copyright: Copyright © 2020 the Author(s). Published by PNAS.
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