Localized Surface Resonance Spectrum Of Monomer/Multimer Of Gold Nanoparticle

As a kind of noble metal nanomaterial, gold nanoparticle has some special opticalproperties, such as strong absorption, strong scattering, surface plasmon resonance and so on.These optical properties depend mainly on the morphology of the particles, modification ofthe functional molecular and changes of the surrounding environment. This inducesresearchers’ extensive interest, and the investigation method is transferring from the ensemblelevel to the single particle level. The studies at single particle level help us to find informationundiscovered at the ensemble level and to provide some proofs for the theoretical simulationexperiments of gold nanoparticles. For example, the study for the relationship of theplasmonic coupling interactions with the distances of particles has to be achieved by themethod of single particle. Although, the dark-field spectral imaging is one of the methodscommonly used on the localized surface resonance spectra (LSPR) of single gold nanoparticle,it lacks the information of nanoparticles’ morphologies, spacing between nanoparticles and isunable to guarantee the spectrum derived from a single particle. Based on the aboveconsiderations, we attempt to do following work:(1) An in situ imaging method of electron microscopy and dark-field microscopy wasdeveloped. Therefore, we can obtain the real single nanoparticle LSPR.(2) The LSPRs of single, dimmer, trimer, and tetramer of gold nanoparticle are observed.The results show that we cannot safely judge whether the spot imaging is derived from singlenanoparticle or two closely gold nanoparticles.(3) We attempt to study a method to identify the heparin by the gold nanoparticles. Theinfluences on the detection sensitivity of temperature, pH value, ionic strength, sampleconcentration, volume are preliminary investigated. We also studied the detection effect of theheparin by gold naorods with positive charges and the result shows that the spectrum has abule shift.