Reconfigurable lithographic structures

{
  "publication_number": "US9108314B2",
  "country": "US",
  "kind": "B2",
  "title": "Reconfigurable lithographic structures",
  "abstract": "A lithographically structured device has an actuation layer and a control layer operatively connected to the actuation layer. The actuation layer includes a stress layer and a neutral layer that is constructed of materials and with a structure such that it stores torsional energy upon being constructed. The control layer is constructed to maintain the actuation layer substantially in a first configuration in a local environmental condition and is responsive to a change in the local environmental condition such that it permits a release of stored torsional energy to cause a change in a structural configuration of the lithographically structured device to a second configuration, the control layer thereby providing a trigger mechanism. The lithographically structured device has a maximum dimension that is less than about 10 mm when it is in the second configuration.",
  "claims": [
    "1. A method of encapsulating or gripping a sub-millimeter size object, comprising: disposing a lithographically structured device proximate said sub-millimeter size object, said lithographically structured device having a first structural configuration; storing torsional energy in said lithographically structured device in said first structural configuration; and changing an environmental condition proximate said lithographically structured device to release said torsional energy to cause said lithographically structured device to change to a second structural configuration to thereby encapsulate or grip said object, wherein said lithographically structured device has a maximum dimension in said second structural configuration that is less than about 1 mm.",
    "2. A method of encapsulating or gripping a sub-millimeter size object according to claim 1, wherein said lithographically structured device comprises a magnetic material and said disposing said lithographically structured device proximate said sub-millimeter size object comprises directing it with a magnetic field.",
    "3. A method of encapsulating or gripping a sub-millimeter size object according to claim 1, wherein said changing an environmental condition proximate said lithographically structured device is a biocompatible change to permit said encapsulating or gripping free from damage to a biological environment.",
    "4. A method of encapsulating or gripping a sub-millimeter size object according to claim 1, wherein said lithographically structured device comprises: an actuation layer; and a control layer operatively connected to said actuation layer, said control layer including a first structural segment, a second structural segment, and a joint between said first and second structural segments, and wherein said torsional energy is stored in said actuation layer.",
    "5. A method of encapsulating or gripping a sub-millimeter size object according to claim 4, wherein said changing to said second structural configuration to thereby encapsulate or grip said object comprises rotating said first and second structural segments with respect to said joint by said release of said torsional energy.",
    "6. A method of encapsulating or gripping a sub-millimeter size object according to claim 4, wherein said changing an environmental condition proximate said lithographically structured device causes a change in stiffness of a material of said joint.",
    "7. A method of encapsulating or gripping a sub-millimeter size object according to claim 1, wherein said changing said environmental condition comprises changing a local temperature to which at least a portion of said lithographically structured device is subjected.",
    "8. A method of encapsulating or gripping a sub-millimeter size object according to claim 7, wherein said changing said environmental condition comprises changing said local temperature by less than about 20° C.",
    "9. A method of encapsulating or gripping a sub-millimeter size object according to claim 7, wherein said changing said environmental condition comprises changing said local temperature by less than about 40° C.",
    "10. A method of encapsulating or gripping a sub-millimeter size object according to claim 1, wherein said changing said environmental condition includes a chemical change.",
    "11. A method of encapsulating or gripping a sub-millimeter size object according to claim 10, wherein said joint comprises a sacrificial material, and said chemical change causes at least a portion of said sacrificial material to be at least one of etched or dissolved.",
    "12. A method of encapsulating or gripping a sub-millimeter size object according to claim 1, further comprising moving said lithographically structured device in said second structural configuration while encapsulating or griping said object to move said object.",
    "13. A method of encapsulating or gripping a sub-millimeter size object according to claim 12, further comprising releasing said object from said lithographically structured device after moving said object.",
    "14. A method of encapsulating or gripping a sub-millimeter size object according to claim 1, wherein said sub-millimeter size object is a portion of a living cell mass, said portion being gripped by said lithographically structured device when changed to said second structural configuration, and wherein the method further comprises extracting said sub-millimeter size object from a remainder of said living cell mass after being gripped by said lithographically structured device.",
    "15. A method of encapsulating or gripping a sub-millimeter size object according to claim 14, wherein said sub-millimeter size object is a cell or group of cells.",
    "16. A method of encapsulating or gripping a sub-millimeter size object according to claim 14, further comprising rotating said lithographically structured device before or during said change to said second structural configuration to extricate said sub-millimeter size object from said remainder of said living cell mass.",
    "17. A method of encapsulating or gripping a sub-millimeter size object according to claim 16, wherein said lithographically structured device cuts through tissue of said living cell mass while rotating to extricate said sub-millimeter size object."
  ],
  "description_excerpt": "1. Field of Invention\n\nThe current invention relates to lithographically produced structures, and more particularly to reconfigurable lithographically produced structures.\n\n2. Discussion of Related Art\n\nLithography, the workhorse of the microelectronics industry, is routinely used to fabricate micro and nanostructures in a highly monodisperse manner, with high accuracy and precision. However, one of the central limitations of this technology is that it is inherently two-dimensional (2D) as a result of the wafer based fabrication paradigm. It is extremely challenging to fabricate three-dimensional (3D) patterned structures, let alone complex structures containing encapsulated objects, on the sub-mm scale. Thus, the parallel fabrication of such structures remains a major challenge that needs to be addressed.\n\nSome solutions have emerged that enable sub-mm scale lithographic fabrication in 3D; these include techniques such as wafer stacking (N. Miki, X. Zhang, R. Khanna, A. A. Ayon, D. Ward, S. M. Spearing, Sens. Actuators, A 2003, 103, 194-201), micromachining (S. Kawata, H. B. Sun, T. Tanaka, K. Takada, Nature 2001, 412, 697-698), molding (L. T. Romankiw, Electrochim. Acta 1997, 42, 2985-3005; L. Weber, W. Ehrfeld, H. Freimuth, M. Lacher, H. Lehr, B. Pech, presented at Micromachining and Microfabrication Process Technology II, Austin, Tex., USA, October 1996), and self-assembly (G. M. Whitesides, B. Grzybowski, Science 2002, 295, 2418-2421). Self-assembly, or self-folding, of 2D lithographically patterned templates is one attractive strategy for fabricating 3D patterned, sub-mm scale structures.",
  "cpc": [
    "B25J 7/00",
    "B81B 2201/031",
    "B81B 3/0024",
    "B81B 3/0032",
    "B81C 99/002",
    "Y10T 436/11"
  ],
  "ipc": [
    "B25J 7/00",
    "B81B 3/00",
    "B81C 99/00",
    "G01N 15/06",
    "G01N 33/00",
    "G01N 33/48"
  ],
  "assignees": [
    "Johns Hopkins University"
  ],
  "inventors": [
    "David H. Gracias",
    "Timothy G. Leong"
  ],
  "filing_date": "2014-03-12",
  "publication_date": "2015-08-18",
  "grant_date": "2015-08-18",
  "priority_date": "2008-03-06",
  "application_number": "US-201414206585-A",
  "family_id": "41056382",
  "cited_by_count": 1,
  "citations": [
    "US7052616B2",
    "US20070020310A1"
  ]
}