The Experts below are selected from a list of 417 Experts worldwide ranked by ideXlab platform

Bryan Kaehr - One of the best experts on this subject based on the ideXlab platform.

  • Direct-write graded index materials realized in protein hydrogels
    Applied Physics Letters, 2016
    Co-Authors: Bryan Kaehr, David Scrymgeour
    Abstract:

    The ability to create optical materials with arbitrary index distributions would prove transformative for optics design and applications. However, current fabrication techniques for graded index (GRIN) materials rely on diffusion profiles and therefore are unable to realize arbitrary distribution GRIN design. Here, we demonstrate the laser direct writing of graded index structures in protein-based hydrogels using Multiphoton Lithography. We show index changes spanning a range of 10−2, which is comparable with laser densified glass and polymer systems. Further, we demonstrate the conversion of these written density variation structures into SiO2, opening up the possibility of transforming GRIN hydrogels to a wide range of material systems.

  • Biocompatible microfabrication of 3D isolation chambers for targeted confinement of individual cells and their progeny.
    Analytical chemistry, 2012
    Co-Authors: Jason C Harper, Susan M. Brozik, C. Jeffrey Brinker, Bryan Kaehr
    Abstract:

    We describe a technique to physically isolate single/individual cells from their surrounding environment by fabricating three-dimensional microchambers around selected cells under biocompatible conditions. Isolation of targeted cells is achieved via rapid fabrication of protein hydrogels from a biocompatible precursor solution using Multiphoton Lithography, an intrinsically 3D laser direct write microfabrication technique. Cells remain chemically accessible to environmental cues enabling their propagation into well-defined, high density populations. We demonstrate this methodology on gram negative (E. coli), gram positive (S. aureus), and eukaryotic (S. cerevisiae) cells. The opportunities to confine viable, single/individual-cells and small populations within user-defined microenvironments afforded by this approach should facilitate the study of cell behaviors across multiple generations.

  • Multiphoton Lithography of nanocrystalline platinum and palladium for site specific catalysis in 3d microenvironments
    Journal of the American Chemical Society, 2012
    Co-Authors: Lauren D Zarzar, B S Swartzentruber, Jason C Harper, Darren R Dunphy, Jeffrey C Brinker, Joanna Aizenberg, Bryan Kaehr
    Abstract:

    Integration of catalytic nanostructured platinum and palladium within 3D microscale structures or fluidic environments is important for systems ranging from micropumps to microfluidic chemical reactors and energy converters. We report a straightforward procedure to fabricate microscale patterns of nanocrystalline platinum and palladium using Multiphoton Lithography. These materials display excellent catalytic, electrical, and electrochemical properties, and we demonstrate high-resolution integration of catalysts within 3D defined microenvironments to generate directed autonomous particle and fluid transport.

  • Multiphoton Lithography of Nanocrystalline Platinum and Palladium for Site-Specific Catalysis in 3D Microenvironments
    2012
    Co-Authors: Lauren D Zarzar, B S Swartzentruber, Jason C Harper, Jeffrey C Brinker, Joanna Aizenberg, Darren R. Dunphy, Bryan Kaehr
    Abstract:

    Integration of catalytic nanostructured platinum and palladium within 3D microscale structures or fluidic environments is important for systems ranging from micropumps to microfluidic chemical reactors and energy converters. We report a straightforward procedure to fabricate microscale patterns of nanocrystalline platinum and palladium using Multiphoton Lithography. These materials display excellent catalytic, electrical, and electrochemical properties, and we demonstrate high-resolution integration of catalysts within 3D defined microenvironments to generate directed autonomous particle and fluid transport

  • Biocompatible Microfabrication of 3D Isolation Chambers for Targeted Confinement of Individual Cells and Their Progeny
    2012
    Co-Authors: Jason C. Harper, Susan M. Brozik, Jeffrey C Brinker, Bryan Kaehr
    Abstract:

    We describe a technique to physically isolate single/individual cells from their surrounding environment by fabricating three-dimensional microchambers around selected cells under biocompatible conditions. Isolation of targeted cells is achieved via rapid fabrication of protein hydrogels from a biocompatible precursor solution using Multiphoton Lithography, an intrinsically 3D laser direct write microfabrication technique. Cells remain chemically accessible to environmental cues enabling their propagation into well-defined, high density populations. We demonstrate this methodology on gram negative (E. coli), gram positive (S. aureus), and eukaryotic (S. cerevisiae) cells. The opportunities to confine viable, single/individual-cells and small populations within user-defined microenvironments afforded by this approach should facilitate the study of cell behaviors across multiple generations

Jason B. Shear - One of the best experts on this subject based on the ideXlab platform.

  • Multiphoton microfabrication of conducting polymer-based biomaterials
    Journal of materials chemistry. B, 2015
    Co-Authors: John G. Hardy, Jason B. Shear, Derek S. Hernandez, Damian M. Cummings, Frances A. Edwards, Christine E. Schmidt
    Abstract:

    We report the application of Multiphoton microfabrication to prepare conducting polymer (CP)-based biomaterials that were capable of drug delivery and interacting with brain tissue ex vivo, thereby highlighting the potential of Multiphoton Lithography to prepare electroactive biomaterials which may function as implantable neural biointerfaces (e.g. electrodes).

  • 3D-printed microfluidic microdissector for high-throughput studies of cellular aging
    Analytical chemistry, 2014
    Co-Authors: Eric C. Spivey, Jason B. Shear, Blerta Xhemalce, Ilya J. Finkelstein
    Abstract:

    Due to their short lifespan, rapid division, and ease of genetic manipulation, yeasts are popular model organisms for studying aging in actively dividing cells. To study replicative aging over many cell divisions, individual cells must be continuously separated from their progeny via a laborious manual microdissection procedure. Microfluidics-based soft-Lithography devices have recently been used to automate microdissection of the budding yeast Saccharomyces cerevisiae. However, little is known about replicative aging in Schizosaccharomyces pombe, a rod-shaped yeast that divides by binary fission and shares many conserved biological functions with higher eukaryotes. In this report, we develop a versatile Multiphoton Lithography method that enables rapid fabrication of three-dimensional master structures for polydimethylsiloxane (PDMS)-based microfluidics. We exploit the rapid prototyping capabilities of Multiphoton Lithography to create and characterize a cell-capture device that is capable of high-resolu...

  • 3D-Printed Microfluidic Microdissector for High-Throughput Studies of Cellular Aging
    2014
    Co-Authors: Eric C. Spivey, Jason B. Shear, Blerta Xhemalce, Ilya J. Finkelstein
    Abstract:

    Due to their short lifespan, rapid division, and ease of genetic manipulation, yeasts are popular model organisms for studying aging in actively dividing cells. To study replicative aging over many cell divisions, individual cells must be continuously separated from their progeny via a laborious manual microdissection procedure. Microfluidics-based soft-Lithography devices have recently been used to automate microdissection of the budding yeast Saccharomyces cerevisiae. However, little is known about replicative aging in Schizosaccharomyces pombe, a rod-shaped yeast that divides by binary fission and shares many conserved biological functions with higher eukaryotes. In this report, we develop a versatile Multiphoton Lithography method that enables rapid fabrication of three-dimensional master structures for polydimethylsiloxane (PDMS)-based microfluidics. We exploit the rapid prototyping capabilities of Multiphoton Lithography to create and characterize a cell-capture device that is capable of high-resolution microscopic observation of hundreds of individual S. pombe cells. By continuously removing the progeny cells, we demonstrate that cell growth and protein aggregation can be tracked in individual cells for over ∼100 h. Thus, the fission yeast lifespan microdissector (FYLM) provides a powerful on-chip microdissection platform that will enable high-throughput studies of aging in rod-shaped cells

  • Multiphoton Lithography of Unconstrained Three-Dimensional Protein Microstructures
    Advanced Functional Materials, 2012
    Co-Authors: Eric C. Spivey, Eric T. Ritschdorff, Jodi L. Connell, Christopher A. Mclennon, Christine E. Schmidt, Jason B. Shear
    Abstract:

    Multiphoton Lithography (MPL) is a highly versatile strategy for creating 3D microscale objects with complex geometrical arrangements, including nested boxes, interlocking blocks, and braided threads. Of the various chemistries used to produce solid forms in MPL, protein photocrosslinking has been of particular value in biological applications, yielding materials with high porosity, tunable elasticity, and a diverse set of chemical and biochemical properties. Unfortunately, the potential for object drift, and consequent distortion, during this direct-write process has required that microforms be constructed in integral contact with an immobile surface, precluding fabrication of protein-based objects that retain rotational and translational degrees of freedom. Here, the development of a high-viscosity protein-based reagent that can be used to fabricate complex 3D microstructures that are not adhered to a surface, including chains of Mobius strips, paddlewheels, and unconstrained (free-floating) probes for bacterial motility, is reported.

  • Multi-focal Multiphoton Lithography.
    Lab on a chip, 2012
    Co-Authors: Eric T. Ritschdorff, Rex Nielson, Jason B. Shear
    Abstract:

    Multiphoton Lithography (MPL) provides unparalleled capabilities for creating high-resolution, three-dimensional (3D) materials from a broad spectrum of building blocks and with few limitations on geometry, qualities that have been key to the design of chemically, mechanically, and biologically functional microforms. Unfortunately, the reliance of MPL on laser scanning limits the speed at which fabrication can be performed, making it impractical in many instances to produce large-scale, high-resolution objects such as complex micromachines, 3D microfluidics, etc. Previously, others have demonstrated the possibility of using multiple laser foci to simultaneously perform MPL at numerous sites in parallel, but use of a stage-scanning system to specify fabrication coordinates resulted in the production of identical features at each focal position. As a more general solution to the bottleneck problem, we demonstrate here the feasibility for performing multi-focal MPL using a dynamic mask to differentially modulate foci, an approach that enables each fabrication site to create independent (uncorrelated) features within a larger, integrated microform. In this proof-of-concept study, two simultaneously scanned foci produced the expected two-fold decrease in fabrication time, and this approach could be readily extended to many scanning foci by using a more powerful laser. Finally, we show that use of multiple foci in MPL can be exploited to assign heterogeneous properties (such as differential swelling) to micromaterials at distinct positions within a fabrication zone.

Eric Mazur - One of the best experts on this subject based on the ideXlab platform.

  • Surface-enhanced Raman scattering hot spot isolation using surface-enhanced Multiphoton Lithography
    Frontiers in Ultrafast Optics: Biomedical Scientific and Industrial Applications X, 2010
    Co-Authors: Eric D. Diebold, Paul Peng, Eric Mazur
    Abstract:

    In this Manuscript, we present the fabrication and spectroscopic characterization of a large-area surfaceenhanced Raman scattering (SERS) substrate, as well as a method for improving femtomole-level trace detection (10 9 molecules) using this substrate. Using Multiphoton-induced exposure of a commercial photoresist, we physically limit the available molecular adsorption sites to only the electromagnetic "hot spots" on the substrate. This process prevents molecules from adsorbing to sites of weak SERS enhancement, while permitting adsorption to sites of extraordinary SERS enhancement. For a randomly adsorbed submonolayer of benzenethiol molecules the average Raman scattering cross-section of the processed sample is 27 times larger than that of an unprocessed SERS substrate.

  • Isolating surface-enhanced Raman scattering hot spots using Multiphoton Lithography.
    Journal of the American Chemical Society, 2009
    Co-Authors: Eric D. Diebold, Paul Peng, Eric Mazur
    Abstract:

    We present a method for improving femtomole-level trace detection (109 molecules) using large-area surface-enhanced Raman scattering (SERS) substrates. Using Multiphoton-induced exposure of a commercial photoresist, we physically limit the available molecular adsorption sites to only the electromagnetic “hot spots” on the substrate. This process prevents molecules from adsorbing to sites of weak SERS enhancement, while permitting adsorption to sites of extraordinary SERS enhancement. For a randomly adsorbed submonolayer of benzenethiol molecules the average Raman scattering cross section of the processed sample is 27 times larger than that of an unprocessed SERS substrate.

David L. Kaplan - One of the best experts on this subject based on the ideXlab platform.

  • 3D Printing of Regenerated Silk Fibroin and Antibody-Containing Microstructures via Multiphoton Lithography
    ACS Biomaterials Science & Engineering, 2017
    Co-Authors: Matthew B. Dickerson, Patrick B. Dennis, Vincent P. Tondiglia, Lloyd J. Nadeau, Kristi M. Singh, Lawrence F. Drummy, Benjamin P. Partlow, Dean P. Brown, Fiorenzo G. Omenetto, David L. Kaplan
    Abstract:

    Regenerated silk fibroin, a biopolymer derived from silkworm cocoons, is a versatile material that has been widely explored for a number of applications (e.g., drug delivery, tissue repair, biocompatible electronics substrates, and optics) due to its attractive biochemical properties and processability. Here, we report on the free-form printing of silk-based, 3D microstructures through Multiphoton Lithography. Utilizing Multiphoton Lithography in conjunction with specific photoinitiator chemistry and postprint cross-linking, a number of microarchitectures were achieved including self-supporting fibroin arches. Further, the straightforward production of high fidelity and biofunctional protein architectures was enabled through the printing of aqueous fibroin/immunoglobulin solutions.

  • 3D Printing of Regenerated Silk Fibroin and Antibody-Containing Microstructures via Multiphoton Lithography
    2017
    Co-Authors: Matthew B. Dickerson, Patrick B. Dennis, Vincent P. Tondiglia, Lloyd J. Nadeau, Kristi M. Singh, Lawrence F. Drummy, Benjamin P. Partlow, Dean P. Brown, Fiorenzo G. Omenetto, David L. Kaplan
    Abstract:

    Regenerated silk fibroin, a biopolymer derived from silkworm cocoons, is a versatile material that has been widely explored for a number of applications (e.g., drug delivery, tissue repair, biocompatible electronics substrates, and optics) due to its attractive biochemical properties and processability. Here, we report on the free-form printing of silk-based, 3D microstructures through Multiphoton Lithography. Utilizing Multiphoton Lithography in conjunction with specific photoinitiator chemistry and postprint cross-linking, a number of microarchitectures were achieved including self-supporting fibroin arches. Further, the straightforward production of high fidelity and biofunctional protein architectures was enabled through the printing of aqueous fibroin/immunoglobulin solutions

Eric D. Diebold - One of the best experts on this subject based on the ideXlab platform.

  • Surface-enhanced Raman scattering hot spot isolation using surface-enhanced Multiphoton Lithography
    Frontiers in Ultrafast Optics: Biomedical Scientific and Industrial Applications X, 2010
    Co-Authors: Eric D. Diebold, Paul Peng, Eric Mazur
    Abstract:

    In this Manuscript, we present the fabrication and spectroscopic characterization of a large-area surfaceenhanced Raman scattering (SERS) substrate, as well as a method for improving femtomole-level trace detection (10 9 molecules) using this substrate. Using Multiphoton-induced exposure of a commercial photoresist, we physically limit the available molecular adsorption sites to only the electromagnetic "hot spots" on the substrate. This process prevents molecules from adsorbing to sites of weak SERS enhancement, while permitting adsorption to sites of extraordinary SERS enhancement. For a randomly adsorbed submonolayer of benzenethiol molecules the average Raman scattering cross-section of the processed sample is 27 times larger than that of an unprocessed SERS substrate.

  • Isolating surface-enhanced Raman scattering hot spots using Multiphoton Lithography.
    Journal of the American Chemical Society, 2009
    Co-Authors: Eric D. Diebold, Paul Peng, Eric Mazur
    Abstract:

    We present a method for improving femtomole-level trace detection (109 molecules) using large-area surface-enhanced Raman scattering (SERS) substrates. Using Multiphoton-induced exposure of a commercial photoresist, we physically limit the available molecular adsorption sites to only the electromagnetic “hot spots” on the substrate. This process prevents molecules from adsorbing to sites of weak SERS enhancement, while permitting adsorption to sites of extraordinary SERS enhancement. For a randomly adsorbed submonolayer of benzenethiol molecules the average Raman scattering cross section of the processed sample is 27 times larger than that of an unprocessed SERS substrate.