| The potential for development of detection systems based on nanoscopic metal particle interaction with the surrounding host environment, as well as with other particles, is discussed. To examine host environment interactions, gold nanoparticles were immobilized on the surface of a glass substrate forming a discontinuous thin film. This film, which constitutes an optical transduction device when placed in contact with analyte-bearing solutions, was utilized in conjunction with UV-Visible spectroscopy to record shifts in the plasmon resonance band as various analyte hosts are introduced into the system. The experimental results are in agreement with theoretical predictions. Enhancement of the detection signal occurs after the films are modified with alkanethiols.; To examine analyte induced interparticle interactions, Au nanospheres are produced via the citrate reduction method and derivatized with two different oligomers. Upon addition of a mutually complementary oligomer target, particle interaction occurs. The spectral results are in agreement with theory. Enhancement of these spectral shifts theoretically occur with alterations to the nanoparticle shape, with rod-rod interactions providing the greatest response. Theoretical considerations are expanded upon to provide a unique perspective on a pair-wise detection system based on gold rod-rod pairs randomly oriented in solution.; In an effort to compare experiment with theory, gold rod nanoparticles are successfully synthesized via an electrochemical method. Control over the particle dimensions is achieved via silver plate immersion. Induced rod aggregates demonstrate distinct spectral shifts that bode well for eventual applications as a detection system.; The current understanding of metal nanorod surface chemistry is an obstacle preventing reversible and controlled aggregation at this current time. Preliminary experimental work is presented which models the rod systems involving two different metals. By confining the metals into template host pores, electromagnetic interactions in the pair particles occur with the particles in known orientations. Experimental results are not as promising as theoretical predictions. This is possibly due to an absorbing oxide or halogen layer on the silver particle causing interference. However, theoretical predictions for this mixed metal rod system provide definite potential for use as optical detection systems once the surface chemistry of non-spherical metal particles is understood. |
