200 research outputs found
Genomic selection and sequencing using encoded microcarriers
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
Biological cilia are versatile hairâlike 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 particleâremoval by selfâcleaning 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 irregularâshaped sand grains both in water and in air. These findings can contribute to the development of novel particulate manipulation and selfâcleaning/antifouling surfaces, which can be applied, e.g., to prevent fouling of (bio)sensors in labâonâaâchip devices, and to prevent biofouling of submerged surfaces such as marine sensors and water quality analyzers
Climbing droplets driven by mechanowetting on transverse waves
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
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 (KDexâ63 kPa vs. Kwaterâ36 kPa, and GDexâ16 kPa vs. Gwaterâ7 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 (ÏDexâ90 s vs. Ïwaterâ15 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
Anti-Biofouling and Self-Cleaning Surfaces Featured with Magnetic Artificial Cilia
The fouling of surfaces submerged in a liquid is a serious problem for many applications including lab-on-a-chip devices and marine sensors. Inspired by the versatility of cilia in manipulating fluids and particles, it is experimentally demonstrated that surfaces partially covered with magnetic artificial cilia (MAC) have the capacity to efficiently prevent attachment and adhesion of real biofouling agentsâmicroalgae Scenedesmus sp. Actuation of the MAC resulted in over 99% removal of the algae for two different scenarios: (1) actuating the MAC immediately after injecting the algae into a microfluidic chip, demonstrating antifouling and (2) starting to actuate the MAC 1 week after injecting the algae into the chip and leaving them to grow in static conditions, showing self-cleaning. It is shown that the local and global flows generated by the actuated MAC are substantial, resulting in hydrodynamic shear forces acting on the algae, which are likely to be key to efficient antifouling and self-cleaning. These findings and insights will potentially lead to novel types of self-cleaning and antifouling strategies, which may have a relevant practical impact on different fields and applications including lab-on-a-chip devices and water quality analyzers
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