Shrinkable silver diffraction grating fabricated inside a hydrogel using 522-nm femtosecond laser

The integration of metal microstructures and soft materials is promising for the realization of novel optical and biomedical devices owing to the flexibility and biocompatibility of the latter. Nevertheless, the fabrication of three-dimensional metal structures within a soft material is still challenging. In this study, we demonstrate the fabrication of a silver diffraction grating inside a biocompatible poly(ethylene glycol) diacrylate (PEGDA) hydrogel by using a 522-nm femtosecond laser via multi-photon photoreduction of silver ions. The optical diffraction pattern obtained with the grating showed equally spaced diffraction spots, which indicated that a regular, periodic silver grating was formed. Notably, the distance between the diffraction spots changed when the water content in the hydrogel was reduced. The grating period decreased when the hydrogel shrank owing to the loss of water, but the straight shapes of the line structures were preserved, which demonstrated the optical tunability of the fabricated structure. Our results demonstrate the potential of the femtosecond laser-based photoreduction technique for the fabrication of novel tunable optical devices as well as highly precise structures.

[1]  E. Palleau,et al.  Reversible patterning and actuation of hydrogels by electrically assisted ionoprinting , 2013, Nature Communications.

[2]  G L Coté,et al.  A fluorescence-based glucose biosensor using concanavalin A and dextran encapsulated in a poly(ethylene glycol) hydrogel. , 1999, Analytical chemistry.

[3]  Shoji Maruo,et al.  Femtosecond laser direct writing of metallic microstructures by photoreduction of silver nitrate in a polymer matrix. , 2008, Optics express.

[4]  M. Sadeghi.  Development of a Temperature - Sensitive Composite Hydrogel for Drug Delivery Applications , 2011 .

[5]  Takuo Tanaka,et al.  Two-Photon Fabrication of Three-Dimensional Metallic Nanostructures for Plasmonic Metamaterials , 2012 .

[6]  Xiaogong Wang,et al.  Aptamer-functionalized hydrogel diffraction gratings for the human thrombin detection. , 2013, Chemical communications.

[7]  Seok Hyun Yun,et al.  Light-guiding hydrogels for cell-based sensing and optogenetic synthesis in vivo , 2013, Nature Photonics.

[8]  Eric Mazur,et al.  Fabrication of disconnected three‐dimensional silver nanostructures in a polymer matrix , 2012 .

[9]  E. Hecht.  Optics 4th Edition , 1998 .

[10]  N. Tsutsumi,et al.  Fabrication of the silver structure through two-photon excitation by femtosecond laser , 2014 .

[11]  Tsuneo Mitsuyu,et al.  Permanent photoreduction of Sm3+ to Sm2+ inside a sodium aluminoborate glass by an infrared femtosecond pulsed laser , 1999 .

[12]  T. S. Ong,et al.  Femtosecond laser application for high capacity optical data storage , 2004 .

[13]  Eli Yablonovitch,et al.  Two‐Photon Photographic Production of Three‐Dimensional Metallic Structures within a Dielectric Matrix , 2000 .

[14]  M. L. Torres-Mapa,et al.  Femtosecond laser direct writing of metal microstructure in a stretchable poly(ethylene glycol) diacrylate (PEGDA) hydrogel. , 2016, Optics letters.

[15]  H. Kong,et al.  The spatiotemporal control of erosion and molecular release from micropatterned poly(ethylene glycol)-based hydrogel. , 2013, Biomaterials.

[16]  Torsten Scherer,et al.  Fabrication of Conductive 3D Gold‐Containing Microstructures via Direct Laser Writing , 2016, Advanced materials.

[17]  Xiaogong Wang,et al.  Polymer diffraction gratings on stimuli-responsive hydrogel surfaces: Soft-lithographic fabrication and optical sensing properties , 2010 .

[18]  Xiang Fei,et al.  Green synthesis of silk fibroin-silver nanoparticle composites with effective antibacterial and biofilm-disrupting properties. , 2013, Biomacromolecules.

[19]  S. Kawata,et al.  Two-photon-induced reduction of metal ions for fabricating three-dimensional electrically conductive metallic microstructure , 2006 .

[20]  Xiaogong Wang,et al.  Hydrogel diffraction grating as sensor: A tool for studying volume phase transition of thermo-responsive hydrogel , 2014 .

[21]  Wataru Sakai,et al.  Two-photon laser fabrication of three-dimensional silver microstructures with submicron scale linewidth , 2011 .

[22]  P. Kishore,et al.  Detection of trace amounts of chromium(VI) using hydrogel coated Fiber Bragg grating , 2017 .

[23]  Satoshi Kawata,et al.  Two-photon photoreduction of metallic nanoparticle gratings in a polymer matrix , 2003 .

[24]  Tommaso Baldacchini,et al.  Multiphoton laser direct writing of two-dimensional silver structures. , 2005, Optics express.

[25]  P. Prasad,et al.  Subwavelength direct laser patterning of conductive gold nanostructures by simultaneous photopolymerization and photoreduction. , 2011, ACS nano.

[26]  Yoshito Y. Tanaka,et al.  Nanopattern Fabrication of Gold on Hydrogels and Application to Tunable Photonic Crystal , 2012, Advanced materials.

[27]  S. Kawata,et al.  Improvement in the reduction of silver ions in aqueous solution using two-photon sensitive dye , 2006 .

[28]  E. Mazur,et al.  One-step direct-laser metal writing of sub-100 nm 3D silver nanostructures in a gelatin matrix , 2015, Nanotechnology.

[29]  Min Gu,et al.  λ/26 silver nanodots fabricated by direct laser writing through highly sensitive two-photon photoreduction , 2013 .

[30]  N. Tsutsumi,et al.  Two-photon excitation by femtosecond laser in poly(N-vinylpyrrolidone) matrix doped with silver ions , 2013 .

[31]  K. Anseth,et al.  Hydrogel Cell Cultures , 2007, Science.

[32]  Donghwa Lee,et al.  Highly conductive and flexible silver nanowire-based microelectrodes on biocompatible hydrogel. , 2014, ACS applied materials & interfaces.

[33]  P. Viktorovitch,et al.  Enhanced localized near field and scattered far field for surface nanophotonics applications , 2012 .

[34]  B. Jia,et al.  Functional Optical Plasmonic Resonators Fabricated via Highly Photosensitive Direct Laser Reduction , 2016 .

[35]  Ali Khademhosseini,et al.  Structural Reinforcement of Cell-Laden Hydrogels with Microfabricated Three Dimensional Scaffolds. , 2014, Biomaterials science.

[36]  Hong-Bo Sun,et al.  Aqueous multiphoton lithography with multifunctional silk-centred bio-resists , 2015, Nature Communications.

[37]  P. Prasad,et al.  Laser Writing of Multiscale Chiral Polymer Metamaterials , 2012 .

[38]  Satoshi Kawata,et al.  3D metallic nanostructure fabrication by surfactant-assisted multiphoton-induced reduction. , 2009, Small.