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  1. Article ; Online: Development of 3D culture scaffolds for directional neuronal growth using 2-photon lithography.

    Agrawal, Lokesh / Saidani, Menouer / Guillaud, Laurent / Terenzio, Marco

    Materials science & engineering. C, Materials for biological applications

    2021  Volume 131, Page(s) 112502

    Abstract: Conventional applications of transplant technology, applied to severe traumatic injuries of the nervous system, have met limited success in the clinics due to the complexity of restoring function to the damaged tissue. Neural tissue engineering aims to ... ...

    Abstract Conventional applications of transplant technology, applied to severe traumatic injuries of the nervous system, have met limited success in the clinics due to the complexity of restoring function to the damaged tissue. Neural tissue engineering aims to deploy scaffolds mimicking the physiological properties of the extracellular matrix to facilitate the elongation of axons and the repair of damaged nerves. However, the fabrication of ideal scaffolds with precisely controlled thickness, texture, porosity, alignment, and with the required mechanical strength, features needed for effective clinical applications, remains technically challenging. We took advantage of state-of-the-art 2-photon photolithography to fabricate highly ordered and biocompatible 3D nanogrid structures to enhance neuronal directional growth. First, we characterized the physical and chemical properties and proved the biocompatibility of said scaffolds by successfully culturing primary sensory and motor neurons on their surface. Interestingly, axons extended along the fibers with a high degree of alignment to the pattern of the nanogrid, as opposed to the lack of directionality observed on flat glass or polymeric surfaces, and could grow in 3D between different layers of the scaffold. The axonal growth pattern observed is highly desirable for the treatment of traumatic nerve damage occurring during peripheral and spinal cord injuries. Thus, our findings provide a proof of concept and explore the possibility of deploying aligned fibrous 3D scaffold/implants for the directed growth of axons, and could be used in the design of scaffolds targeted towards the restoration and repair of lost neuronal connections.
    MeSH term(s) Axons ; Nerve Regeneration ; Nerve Tissue ; Neurons ; Tissue Engineering ; Tissue Scaffolds
    Language English
    Publishing date 2021-10-21
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2012160-X
    ISSN 1873-0191 ; 0928-4931
    ISSN (online) 1873-0191
    ISSN 0928-4931
    DOI 10.1016/j.msec.2021.112502
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Rotating Circular Micro-Platform with Integrated Waveguides and Latching Arm for Reconfigurable Integrated Optics.

    Briere, Jonathan / Elsayed, Mohannad Y / Saidani, Menouer / Bérard, Martin / Beaulieu, Philippe-Olivier / Rabbani-Haghighi, Hadi / Nabki, Frederic / Ménard, Michaël

    Micromachines

    2017  Volume 8, Issue 12

    Abstract: This work presents a laterally rotating micromachined platform integrated under optical waveguides to control the in-plane propagation direction of light within a die to select one of multiple outputs. The platform is designed to exhibit low constant ... ...

    Abstract This work presents a laterally rotating micromachined platform integrated under optical waveguides to control the in-plane propagation direction of light within a die to select one of multiple outputs. The platform is designed to exhibit low constant optical losses throughout the motion range and is actuated electrostatically using an optimized circular comb drive. An angular motion of ±9.5° using 180 V is demonstrated. To minimize the optical losses between the moving and fixed parts, a gap-closing mechanism is implemented to reduce the initial air gap to submicron values. A latch structure is implemented to hold the platform in place with a resolution of 0.25° over the entire motion range. The platform was integrated with silicon nitride waveguides to create a crossbar switch and preliminary optical measurements are reported. In the bar state, the loss was measured to be 14.8 dB with the gap closed whereas in the cross state it was 12.2 dB. To the authors' knowledge, this is the first optical switch based on a rotating microelectromechanical device with integrated silicon nitride waveguides reported to date.
    Language English
    Publishing date 2017-12-01
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2620864-7
    ISSN 2072-666X
    ISSN 2072-666X
    DOI 10.3390/mi8120354
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: High-resolution Fresnel zone plate fabrication by achromatic spatial frequency multiplication with extreme ultraviolet radiation.

    Sarkar, Sankha Subhra / Solak, Harun H / Saidani, Menouer / David, Christian / van der Veen, J Friso

    Optics letters

    2011  Volume 36, Issue 10, Page(s) 1860–1862

    Abstract: We used an approach based on the self-imaging property of gratings to fabricate high-resolution Fresnel zone plates (FZPs). Under certain conditions, the illumination of a parent ZP with a wideband EUV beam produces a radially oscillating intensity ... ...

    Abstract We used an approach based on the self-imaging property of gratings to fabricate high-resolution Fresnel zone plates (FZPs). Under certain conditions, the illumination of a parent ZP with a wideband EUV beam produces a radially oscillating intensity distribution with double the spatial frequency of the ZP. This intensity distribution is observed in a certain distance range, given by the local zone width, the focal length of the ZP, and the spectral bandwidth of the illuminating beam. This phenomenon has been used to lithographically record daughter ZPs that have approximately half the zone width, thus twice the resolution, of the parent ZP. FZPs with zone widths as low as 30 nm have been fabricated in this way. Use of this technique in the extreme ultraviolet (EUV) region has the potential for high throughput production of FZPs and similar high-resolution diffraction optics with variable spatial frequency for the EUV and x-ray regions.
    Language English
    Publishing date 2011-05-15
    Publishing country United States
    Document type Journal Article
    ISSN 1539-4794
    ISSN (online) 1539-4794
    DOI 10.1364/OL.36.001860
    Database MEDical Literature Analysis and Retrieval System OnLINE

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