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Morten Bo Lindholm Mikkelsen

Bio: Morten Bo Lindholm Mikkelsen is an academic researcher from Technical University of Denmark. The author has contributed to research in topics: Nanoimprint lithography & Photolithography. The author has an hindex of 9, co-authored 16 publications receiving 253 citations.

Papers
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TL;DR: In this article, a planar fabrication scheme for fluidic systems with silicon dioxide nanochannels and assess the waferscale quality and homogeneity of the fabricated devices is presented. But the technique is based on well-controlled growth of silicon dioxide, UV lithography, etching, with an etch-stop layer, and glass to silicon dioxide fusion bonding.
Abstract: We present a planar fabrication scheme for fluidic systems with silicon dioxide nanochannels and assess the waferscale quality and homogeneity of the fabricated devices. The nanochannels have heights h ranging from 14 to 300 nm and widths w of 2.5, 5 and 10 μm. Compared to other state-of-the-art fabrication techniques, our double thermal oxidation scheme (DTOS) displays improvements with respect to 4 inch waferscale height variation σh 1.1 nm and low surface roughness Ra 0. 5n m. Our technique is based on well-controlled growth of silicon dioxide, UV lithography, etching, with an etch-stop layer, and glass to silicon dioxide fusion bonding. The smallest achievable channel height is controlled by the precision of oxide growth. The fusion bonding protocol is capable of producing very high aspect ratios, w/h > 2500. We test the devices by measuring capillary filling speed in different channel heights, ranging from 14 to 310 nm. These tests reproduce as well as extend the results reported by Tas et al (2004 Appl. Phys. Lett. 85 3274). A systematic deviation from bulk behaviour has been observed for channel heights below 100 nm. (Some figures in this article are in colour only in the electronic version)

82 citations

Journal ArticleDOI
TL;DR: The motion of linear and circular DNA molecules is studied under pressure driven buffer flow in a 50 nm slit channel with arrays of transverse 150 nm deep nanogrooves, where molecules exhibit size- and topology-dependent velocities.
Abstract: The motion of linear and circular DNA molecules is studied under pressure driven buffer flow in a 50 nm slit channel with arrays of transverse 150 nm deep nanogrooves. Transport occurs through two states of propagation unique to this nanogroove geometry, a slow, stepwise groove-to-groove translation called the "sidewinder" and a fast, continuous tumbling across the grooves called the "tumbleweed". Dynamical transitions between the two states are observed at fixed buffer velocity. Molecules exhibit size- and topology-dependent velocities.

46 citations

Journal ArticleDOI
TL;DR: A one-step photochemical process to coat the inner surfaces of closed microfluidic channels with a nanometer thick layer of PEG, well known to strongly reduce non-specific adsorption, using only commercially available reagents in an aqueous environment is presented.
Abstract: Definable surface chemistry is essential for many applications of microfluidic polymer systems. However, small cross-section channels with a high surface to volume ratio enhance passive adsorption of molecules that depletes active molecules in solution and contaminates the channel surface. Here, we present a one-step photochemical process to coat the inner surfaces of closed microfluidic channels with a nanometer thick layer of poly(ethylene glycol) (PEG), well known to strongly reduce non-specific adsorption, using only commercially available reagents in an aqueous environment. The coating consists of PEG diacrylate (PEGDA) covalently grafted to polymer surfaces via UV light activation of the water soluble photoinitiator benzoyl benzylamine, a benzophenone derivative. The PEGDA coating was shown to efficiently limit the adsorption of antibodies and other proteins to <5% of the adsorbed amount on uncoated polymer surfaces. The coating could also efficiently suppress the adhesion of mammalian cells as demonstrated using the HT-29 cancer cell line. In a subsequent equivalent process step, protein in aqueous solution could be anchored onto the PEGDA coating in spatially defined patterns with a resolution of <15 μm using an inverted microscope as a projection lithography system. Surface patterns of the cell binding protein fibronectin were photochemically defined inside a closed microfluidic device that was initially homogeneously coated by PEGDA. The resulting fibronectin patterns were shown to greatly improve cell adhesion compared to unexposed areas. This method opens for easy surface modification of closed microfluidic systems through combining a low protein binding PEG-based coating with spatially defined protein patterns of interest.

23 citations

Journal ArticleDOI
TL;DR: In this article, a spring-loaded adapter was used for instant heating and cooling of wafer-type substrates in standard hot embossing equipment by using the well-known concept of a clamped stack of stamp and substrate, pre-assembled in an alignment fixture.

22 citations

Journal ArticleDOI
TL;DR: In imprinting sol-gel materials with a multi-level stamp comprising micro- and nanofeatures, channels of different depth are produced in a single process step, enabling fabrication of high-quality nanofluidic devices without expensive high-vacuum lithography and etching techniques.
Abstract: We present a simple and cheap method for fabrication of silica nanofluidic devices for single-molecule studies. By imprinting sol-gel materials with a multi-level stamp comprising micro- and nanofeatures, channels of different depth are produced in a single process step. Calcination of the imprinted hybrid sol-gel material produces purely inorganic silica, which has very low autofluorescence and can be fusion bonded to a glass lid. Compared to top-down processing of fused silica or silicon substrates, imprint of sol-gel silica enables fabrication of high-quality nanofluidic devices without expensive high-vacuum lithography and etching techniques. The applicability of the fabricated device for single-molecule studies is demonstrated by measuring the extension of DNA molecules of different lengths confined in the nanochannels.

21 citations


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01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations

Journal ArticleDOI
TL;DR: Nanoimprint lithography (NIL) is a high throughput, high-resolution parallel patterning method in which a surface pattern of a stamp is replicated into a material by mechanical contact and three dimensional material displacement.
Abstract: Nanoimprint lithography (NIL) is a high throughput, high-resolution parallel patterning method in which a surface pattern of a stamp is replicated into a material by mechanical contact and three dimensional material displacement. This can be done by shaping a liquid followed by a curing process for hardening, by variation of the thermomechanical properties of a film by heating and cooling, or by any other kind of shaping process using the difference in hardness of a mold and a moldable material. The local thickness contrast of the resulting thin molded film can be used as a means to pattern an underlying substrate on wafer level by standard pattern transfer methods, but also directly in applications where a bulk modified functional layer is needed. Therefore it is mainly aimed toward fields in which electron beam and high-end photolithography are costly and do not provide sufficient resolution at reasonable throughput. The aim of this review is to play between two poles: the need to establish standard processes and tools for research and industry, and the issues that make NIL a scientific endeavor. It is not the author’s intention to duplicate the content of the reviews already published, but to look on the NIL process as a whole. The author will also address some issues, which are not covered by the other reviews, e.g., the origin of NIL and the misconceptions, which sometimes dominate the debate about problems of NIL, and guide the reader to issues, which are often forgotten or overlooked.

715 citations

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425 citations

Journal ArticleDOI
TL;DR: From a physics view these systems are fascinating as they enable probing of single-molecule conformation in environments with dimensions that intersect key physical length-scales in the 1 nm to 100 µm range.
Abstract: DNA is the central storage molecule of genetic information in the cell, and reading that information is a central problem in biology. While sequencing technology has made enormous advances over the past decade, there is growing interest in platforms that can readout genetic information directly from long single DNA molecules, with the ultimate goal of single-cell, single-genome analysis. Such a capability would obviate the need for ensemble averaging over heterogeneous cellular populations and eliminate uncertainties introduced by cloning and molecular amplification steps (thus enabling direct assessment of the genome in its native state). In this review, we will discuss how the information contained in genomic-length single DNA molecules can be accessed via physical confinement in nanochannels. Due to self-avoidance interactions, DNA molecules will stretch out when confined in nanochannels, creating a linear unscrolling of the genome along the channel for analysis. We will first review the fundamental physics of DNA nanochannel confinement--including the effect of varying ionic strength--and then discuss recent applications of these systems to genomic mapping. Apart from the intense biological interest in extracting linear sequence information from elongated DNA molecules, from a physics view these systems are fascinating as they enable probing of single-molecule conformation in environments with dimensions that intersect key physical length-scales in the 1 nm to 100 µm range.

331 citations

Journal ArticleDOI
TL;DR: In this paper, a review of spatially confined, non-equilibrium physics in nanoporous media is presented. And a particular emphasis is put on texture formation upon crystallisation in nanopore-confined condensed matter, a topic both of high fundamental interest and of increasing nanotechnological importance.
Abstract: Spatial confinement in nanoporous media affects the structure, thermodynamics and mobility of molecular soft matter often markedly. This article reviews thermodynamic equilibrium phenomena, such as physisorption, capillary condensation, crystallisation, self-diffusion, and structural phase transitions as well as selected aspects of the emerging field of spatially confined, non-equilibrium physics, i.e. the rheology of liquids, capillarity-driven flow phenomena, and imbibition front broadening in nanoporous materials. The observations in the nanoscale systems are related to the corresponding bulk phenomenologies. The complexity of the confined molecular species is varied from simple building blocks, like noble gas atoms, normal alkanes and alcohols to liquid crystals, polymers, ionic liquids, proteins and water. Mostly, experiments with mesoporous solids of alumina, gold, carbon, silica, and silicon with pore diameters ranging from a few up to 50 nm are presented. The observed peculiarities of nanopore-confined condensed matter are also discussed with regard to applications. A particular emphasis is put on texture formation upon crystallisation in nanoporous media, a topic both of high fundamental interest and of increasing nanotechnological importance, e.g. for the synthesis of organic/inorganic hybrid materials by melt infiltration, the usage of nanoporous solids in crystal nucleation or in template-assisted electrochemical deposition of nano structures.

246 citations