Rapid detection and identification of energetic materials with surface enhanced raman spectrometry (sers)

Abstract

In one embodiment, a system includes a plurality of metal nanoparticles functionalized with a plurality of organic molecules tethered thereto, each organic molecule having a primary face and a secondary face. The plurality of organic molecules preferentially interact with the one or more analytes when placed in proximity therewith. The plurality of organic molecules comprise one or more of: one or more modifying groups on the primary face in place of one or more primary hydroxyl groups; and one or more modifying groups on the secondary face in place of one or more secondary hydroxyl groups. At least one of the one or more analytes is an energetic compound. In another embodiment, a method includes chemically modifying a plurality of cyclodextrin molecules at a primary hydroxyl moiety to create a chemical handle; and tethering the plurality of cyclodextrin molecules to a metal nanoparticle using the chemical handle.

What is claimed is: 
     
         1 . A system, comprising:
 a plurality of metal nanoparticles functionalized with a plurality of organic molecules tethered thereto, each organic molecule having a primary face and a secondary face,   wherein the plurality of organic molecules are characterized by preferentially interacting with one or more analytes when placed in proximity therewith,   wherein the plurality of organic molecules comprise one or more of:
 one or more modifying groups on the primary face in place of one or more primary hydroxyl groups; and 
 one or more modifying groups on the secondary face in place of one or more secondary hydroxyl groups, 
   wherein at least one of the one or more analytes is an energetic compound.   
     
     
         2 . The system as recited in  claim 1 , wherein the one or more analytes are selected from a group consisting of: trinitrotoluene (TNT), tetrahexamine tetranitramine (HMX), cyclotrimethylenetrinitramine (RDX), pentaerythritol tetranitrate (PETN), 2,4,6-trinitrophenylmethylnitramine (Tetryl), and peroxides. 
     
     
         3 . The system as recited in  claim 1 , wherein at least some of the plurality of organic molecules are molecules of modified cyclodextrin. 
     
     
         4 . The system of  claim 3 , wherein the cyclodextrin molecules are chemically modified at a primary hydroxyl moiety to tether to a surface of the plurality of metal nanoparticles via a chemical handle. 
     
     
         5 . The system of  claim 4 , wherein the chemical handle is at least one of: a thiol functionality and an amine functionality. 
     
     
         6 . The system of  claim 3 , wherein the plurality of modified cyclodextrin molecules include at least one modifying group on a primary face in place of one or more primary hydroxyl groups. 
     
     
         7 . The system of  claim 6 , wherein the modifying groups are selected from a group consisting of: N 3 , RSH, ROH, RNH 2 , RO Θ , RS Θ , and R 2 N Θ , wherein R is any carbon containing group, or any modifying group. 
     
     
         8 . The system of  claim 3 , wherein the plurality of modified cyclodextrin molecules include at least one modifying group on a secondary face in place of one or more secondary hydroxyl groups. 
     
     
         9 . The system of  claim 8 , wherein the modifying groups are selected from a group consisting of: N 3 , RSH, ROH, RNH 2 , RO Θ , RS Θ , and R 2 N Θ , wherein R is any carbon containing group, or any modifying group. 
     
     
         10 . The system of  claim 3 , wherein the plurality of modified cyclodextrin molecules include one or more modifying groups on a primary face in place of one or more primary hydroxyl groups and one or more modifying groups on a secondary face in place of one or more secondary hydroxyl groups. 
     
     
         11 . The system of  claim 10 , wherein the modifying groups are selected from a group consisting of: N 3 , RSH, ROH, RNH 2 , RO Θ , RS®, and R 2 N Θ , wherein R is any carbon containing group, or any modifying group. 
     
     
         12 . The system as recited in  claim 1 , further comprising a substrate,
 wherein the plurality of metal nanoparticles are attached to the substrate, and   wherein the substrate comprises one of: silicon, glass, an aerogel having an inorganic matrix, and an aerogel having an organic matrix.   
     
     
         13 . A method, comprising:
 chemically modifying a plurality of cyclodextrin molecules at a primary hydroxyl moiety to create a chemical handle; and   tethering the plurality of cyclodextrin molecules to a metal nanoparticle using the chemical handle.   
     
     
         14 . The method of  claim 13 , wherein the chemical handle is at least one of: a thiol functionality and an amine functionality. 
     
     
         15 . The method of  claim 13 , further comprising attaching a plurality of the metal nanoparticles having cyclodextrin molecules tethered thereto to a substrate. 
     
     
         16 . The method of  claim 15 , wherein the substrate is selected from a group consisting of: silicon, silicon compounds, glass, and aerogels. 
     
     
         17 . The method of  claim 13 , further comprising chemically modifying the plurality of cyclodextrin molecules on a primary face via monotosylation of at least one primary hydroxyl group followed by nucleophilic displacement with an appropriate modifying group. 
     
     
         18 . The method of  claim 13 , further comprising chemically modifying the plurality of cyclodextrin molecules on a primary face via ditosylation of at least two primary hydroxyl groups followed by nucleophilic displacement with appropriate modifying groups. 
     
     
         19 . The method of  claim 13 , further comprising chemically modifying the plurality of cyclodextrin molecules on a secondary face via alkylation with an alkylating agent which becomes trapped in a cavity of the cyclodextrin molecule causing preferential reacting with one or more secondary hydroxyl groups. 
     
     
         20 . The method of  claim 13 , further comprising chemically modifying the plurality of cyclodextrin molecules on a secondary face by capping a primary face with tertbutyldimethylsilyl chloride (TBDMSCl) to form hexasilylated cyclodextrin, followed by nucleophilic displacement of one or more secondary hydroxyl groups with an appropriate modifying group.