There remains a continuing threat of terrorist/insurgent attacks on military/civilian personnel and key strategic infrastructures both within the UK mainland and in operational theatres. The development of a novel, innovative, low cost, field deployable bionanosensor, which will have the capability to detect low levels of explosive in a multiplexed fashion is required. The use of the specific interaction between small molecules and biological capture molecules such as antibodies coupled with the detection technique of surface enhanced Raman scattering (SERS) allows a ‘one shot’ analysis.This research makes use of antibody functionalised silver nanoparticles for the detection of the explosives TNT, RDX and PETN by surface enhanced Raman scattering (SERS). Commercially available antibodies specific for TNT and RDX have been modified to specifically orientate ‘flat’ on the surface of silver nanoparticles bringing the target close enough to the metal surface to allow an intrinsic SERS signal of the target molecule to be obtained. Quantitative detection of TNT and RDX explosives was achieved, with pM sensitivity demonstrated for RDX. Furthermore, TNT was detected in two different types of dirt, natural and synthetic dirt in order to mimic a more realistic matrix in which TNT would be found in the field.However, for the detection of PETN, it was required to develop a method to modify a PETN antibody in-house, to specifically orientate ‘flat’ on the nanoparticles surface similarly to the commercially available antibodies. This was achieved by using carbodiimide chemistry and the antibody was purified by cartridge centrifugation and HPLC.The PETN modified antibody was then functionalised onto silver nanoparticles and detection of PETN was achieved by SERS. In addition, PCA was used to allow multiplexed analysis based on unique Raman bands for the three different explosives which could be clearly identified in the SERS spectra.Finally, TNT was detected by using magnetic nanoparticles which were functionalised with a terminal amine group in combination with FITC modified TNT antibody functionalised silver nanoparticles. This assay was designed to allow for the formation of a Meisenheimer complex in the presence of TNT, between the amine functionalised magnetic nanoparticles and the TNT. Furthermore, the TNT antibody functionalised silver nanoparticles also binds to TNT, aggregating the nanoparticles. The magnetic nanoparticles were subsequently used to remove the nanoparticle assembly from the matrix, resulting in a concentrated sample on the magnet, resulting in an increase in SERS.
|Date of Award||24 Jun 2016|
- University Of Strathclyde
|Sponsors||EPSRC (Engineering and Physical Sciences Research Council)|
|Supervisor||Karen Faulds (Supervisor) & Duncan Graham (Supervisor)|