Fabrication of a single sub-micron pore spanning a single crystal (100) diamond membrane and impact on particle translocation

The fabrication of sub-micron pores in single crystal diamond membranes, which span the entirety of the membrane, is described for the first time, and the translocation properties of polymeric particles through the pore investigated. The pores are produced using a combination of laser micromachining to form the membrane and electron beam induced etching to form the pore. Single crystal diamond as the membrane material, has the advantages of chemical stability and durability, does not hydrate and swell, has outstanding electrical properties that facilitate fast, low noise current-time measurements and is optically transparent for combined optical-conductance sensing. The resulting pores are characterized individually using both conductance measurements, employing a microcapillary electrochemical setup, and electron microscopy. Proof-of-concept experiments to sense charged polystyrene particles as they are electrophoretically driven through a single diamond pore are performed, and the impact of this new pore material on particle translocation is explored. These findings reveal the potential of diamond as a platform for pore-based sensing technologies and pave the way for the fabrication of single nanopores which span the entirety of a diamond membrane

High aspect ratio diamond microelectrode array for neuronal activity measurements

International audienceDiamond exhibits several attractive properties for bio-sensing applications. In particular its high bio inertness, high electrochemical stability, and optical transparency provide diamond with high interests for neural activity study. The purpose of this study is the realisation of microelectrodes arrays (MEA) in diamond for neurons slices study. Due to a cellular lysis on the edge of the tissue slices studied, electrodes have to be at least 60 μm in height even though the electrode surface has to be minimised in order to achieve good signal noise rate. Silicon MEA with metal contacts were realised using (Deep Reactive Ion Etching) DRIE and coated with Nanocrystaline Diamond (NCD) using (Bias Enhanced Nucleation) BEN technique. We focus the study on the understanding of the BEN nucleation process on such high aspect ratio electrodes. Several parameters such as slope of the substrate, conductivity and chemical nature of the substrate were studied in order to enable selective nucleation necessary to fabricate diamond MEAs. The study leads to the optimised development of a processing route enabling the selective coating of the active tips of high aspect ratio MEAs without altering the electrical insulation between probes

Local bio-sensitization of nanocrystalline boron doped diamond surfaces with biotin using electrospotting

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Transparent diamond-on-glass micro-electrode arrays for ex-vivo neuronal study

We report on the fabrication of high aspect ratio diamond Micro Electrode Arrays (MEAs) grown on silicon as well as on glass substrates using an optimised nanoseeding technique and Bias Enhanced Nucleation (BEN). Such MEA systems combine high electrode reactivity and high electrical current injection limits with resiliency, biocompatibility and optical transparency of diamond surfaces. We present the technological steps for the fabrication of 2D as well as 3D diamond microelectrode arrays. The patterning issues involve the use of detonation nanodiamond particles (DND)

Transparent diamond-on-glass micro-electrode arrays for ex-vivo neuronal study

We report on the fabrication of high aspect ratio diamond Micro Electrode Arrays (MEAs) grown on silicon as well as on glass substrates using an optimised nanoseeding technique and Bias Enhanced Nucleation (BEN). Such MEA systems combine high electrode reactivity and high electrical current injection limits with resiliency, biocompatibility and optical transparency of diamond surfaces. We present the technological steps for the fabrication of 2D as well as 3D diamond microelectrode arrays. The patterning issues involve the use of detonation nanodiamond particles (DND)

Direct nanopatterning of commercially pure titanium with ultra-nanocrystalline diamond stamps

In order to directly imprint features into a hard metal such as titanium, an imprinting stamp composed of material of greater hardness is required. Diamond is the hardest known material, so is an obvious choice for the production of direct-imprint stamps. Diamond also benefits from a low surface energy, chemical inertness, high resistance to wear and is easily cleaned of contaminants, further favouring it as a stamp material of choice. Chemical vapour deposited ultra-nanocrystalline diamond (UNCD) provides similar mechanical properties to bulk single crystal diamond and can be deposited across large surface areas. This work examines the use of UNCD as a stamp medium for the transfer of nanoscale features into commercially pure titanium (cpTi) substrates. Development of an efficient and viable method for nanopatterning large, non-planar cpTi surfaces is highly desirable to control cell adhesion on the surface of bio-implants. The fabrication of UNCD nanoimprint stamps is detailed and the ability of UNCD to imprint cpTi is illustrated. A square-ordered matrix of 200 nm diameter pillars over a quarter mm square area are shown to be imprinted with the depth quantified against load (kg). The limitations of the technology are also discussed