A reversible molecular valve.

In everyday life, a macroscopic valve is a device with a movable control element that regulates the flow of gases or liquids by blocking and opening passageways. Construction of such a device on the nanoscale level requires (i) suitably proportioned movable control elements, (ii) a method for operating them on demand, and (iii) appropriately sized passageways. These three conditions can be fulfilled by attaching organic, mechanically interlocked, linear motor molecules that can be operated under chemical, electrical, or optical stimuli to stable inorganic porous frameworks (i.e., by self-assembling organic machinery on top of an inorganic chassis). In this article, we demonstrate a reversibly operating nanovalve that can be turned on and off by redox chemistry. It traps and releases molecules from a maze of nanoscopic passageways in silica by controlling the operation of redox-activated bistable [2]rotaxane molecules tethered to the openings of nanopores leading out of a nanoscale reservoir.

[1]  O. Lebedev,et al.  Structure of nanoscale mesoporous silica spheres , 2003 .

[2]  M. Vallet‐Regí,et al.  Mesoporous SBA-15 HPLC evaluation for controlled gentamicin drug delivery. , 2004, Journal of controlled release : official journal of the Controlled Release Society.

[3]  J. S. Beck,et al.  Ordered mesoporous molecular sieves synthesized by a liquid-crystal template mechanism , 1992, Nature.

[4]  Xiang Zhang,et al.  The metastability of an electrochemically controlled nanoscale machine on gold surfaces. , 2004, Chemphyschem : a European journal of chemical physics and physical chemistry.

[5]  David J. Williams,et al.  Molecular LEGO. 1. Substrate-directed synthesis via stereoregular Diels-Alder oligomerizations , 1992 .

[6]  I. Haller.  Covalently attached organic monolayers on semiconductor surfaces , 1978 .

[7]  J. Xue,et al.  PLGA/mesoporous silica hybrid structure for controlled drug release. , 2004, Journal of controlled release : official journal of the Controlled Release Society.

[8]  Euan R. Kay,et al.  A Reversible Synthetic Rotary Molecular Motor , 2004, Science.

[9]  K. Unger,et al.  MCM-41, MCM-48 and related mesoporous adsorbents: their synthesis and characterisation , 2001 .

[10]  James R Heath,et al.  Whence Molecular Electronics? , 2004, Science.

[11]  J. B. Higgins,et al.  A new family of mesoporous molecular sieves prepared with liquid crystal templates , 1992 .

[12]  Hsian-Rong Tseng,et al.  An operational supramolecular nanovalve. , 2004, Journal of the American Chemical Society.

[13]  W. Hertl.  Mechanism of gaseous siloxane reaction with silica. II , 1968 .

[14]  B. Roth,et al.  2,4-Diamino-5-benzylpyrimidines and analogs as antibacterial agents. 9. Lipophilic trimethoprim analogs as antigonococcal agents , 1988 .

[15]  J. F. Stoddart,et al.  Heterosupramolecular Chemistry: Recognition Initiated and Inhibited Silver Nanocrystal Aggregation by Pseudorotaxane Assembly , 2000 .

[16]  Mihail Barboiu,et al.  Dynamic chemical devices: Modulation of contraction/extension molecular motion by coupled-ion binding/pH change-induced structural switching , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[17]  Victor S-Y Lin,et al.  A mesoporous silica nanosphere-based carrier system with chemically removable CdS nanoparticle caps for stimuli-responsive controlled release of neurotransmitters and drug molecules. , 2003, Journal of the American Chemical Society.

[18]  Kimoon Kim,et al.  A pseudorotaxane on gold: formation of self-assembled monolayers, reversible dethreading and rethreading of the ring, and ion-gating behavior. , 2003, Angewandte Chemie.

[19]  Larry A. Sklar,et al.  Control of Molecular Transport Through Stimuli‐Responsive Ordered Mesoporous Materials , 2003 .

[20]  Tohru Yamamoto,et al.  Two-dimensional molecular electronics circuits. , 2002, Chemphyschem : a European journal of chemical physics and physical chemistry.

[21]  Chih-Ming Ho,et al.  A nanomechanical device based on linear molecular motors , 2004 .

[22]  M. Cima,et al.  A controlled-release microchip , 1999, Nature.

[23]  Robert Langer,et al.  In vivo release from a drug delivery MEMS device. , 2004, Journal of controlled release : official journal of the Controlled Release Society.

[24]  Rebecca S. Shawgo,et al.  Repeated in vivo electrochemical activation and the biological effects of microelectromechanical systems drug delivery device. , 2004, Journal of biomedical materials research. Part A.

[25]  Plamen Atanassov,et al.  Photoregulation of Mass Transport through a Photoresponsive Azobenzene-Modified Nanoporous Membrane , 2004 .

[26]  Chih-Ming Ho,et al.  Mechanical Shuttling of Linear Motor-Molecules in Condensed Phases on Solid Substrates , 2004 .

[27]  Y. Bae,et al.  Electrically credible polymer gel for controlled release of drugs , 1991, Nature.

[28]  Hsian-Rong Tseng,et al.  Toward chemically controlled nanoscale molecular machinery. , 2003, Angewandte Chemie.

[29]  Hsian-Rong Tseng,et al.  Molecular-mechanical switch-based solid-state electrochromic devices. , 2004, Angewandte Chemie.

[30]  T. Taguchi,et al.  Photo-Switched Storage and Release of Guest Molecules in the Pore Void of Coumarin-Modified MCM-41 , 2003 .

[31]  Itamar Willner,et al.  Electrical contacting of glucose oxidase in a redox-active rotaxane configuration. , 2004, Angewandte Chemie.

[32]  S. G. Entelis,et al.  KINETICS AND MECHANISM OF THE REACTIONS OF ISOCYANATES WITH COMPOUNDS CONTAINING "ACTIVE" HYDROGEN , 1966 .

[33]  Donald Fitzmaurice,et al.  Assembly of an electronically switchable rotaxane on the surface of a titanium dioxide nanoparticle. , 2003, Journal of the American Chemical Society.

[34]  J. F. Stoddart,et al.  The role of physical environment on molecular electromechanical switching. , 2004, Chemistry.

[35]  William A. Goddard,et al.  Meccano on the Nanoscale—A Blueprint for Making Some of the World's Tiniest Machines , 2004 .

[36]  D. D. Perrin,et al.  Purification of laboratory chemicals , 1966 .

[37]  S. J. van der Molen,et al.  One-way optoelectronic switching of photochromic molecules on gold. , 2003, Physical review letters.

[38]  Maria Consuelo Jimenez-Molero,et al.  Rotaxanes and catenanes as prototypes of molecular machines and motors , 2004 .

[39]  Hsian-Rong Tseng,et al.  Molecular shuttles based on tetrathiafulvalene units and 1,5-dioxynaphthalene ring systems. , 2004, Chemistry.

[40]  B. Feringa,et al.  Exploring the boundaries of a light-driven molecular motor design: new sterically overcrowded alkenes with preferred direction of rotation. , 2004, Organic & biomolecular chemistry.

[41]  Masahiro Fujiwara,et al.  Photocontrolled reversible release of guest molecules from coumarin-modified mesoporous silica , 2003, Nature.

[42]  Frantisek Svec,et al.  Monolithic valves for microfluidic chips based on thermoresponsive polymer gels , 2003, Electrophoresis.

[43]  J. F. Stoddart,et al.  Heterosupramolecular chemistry: programmed pseudorotaxane assembly at the surface of a nanocrystal. , 1999, Angewandte Chemie.