Study Of Localized Surface Plasmon Resonance Enhanced Electrochemiluminescence And Electrochemistry

The excitation of localized surface plasmon resonance(LSPR)occurs when a discontinuous nanostructured material with high free-electron mobility interacts with photons that match the resonance energy of the collective oscillation of the surface valence electrons.As a result of LSPR excitation,a strong electro-magnetic field and a high concentration of energetic charge carriers(electron-hole pairs)are generated at the nano-structured surface.The LSPR effect in turn enhances the ECL luminescence efficiency of the quantum dots.Based on the LSPR enhancement,the following two systems were designed for the improvement of electrochemiluminescence efficiency of quantum dots and the positioning accuracy of SECM:1.LSPR Enhanced Electrochemiluminescence SensorDue to the localized surface plasmon resonance(LSPR),the enhanced local electric field on the surface of the metal nanoparticles(NPs)close to the quantum dots(QDs)can significantly enhance the ECL signal of QDs.In this strategy,a LSPR enhanced ECL sensor based on DNA tetrahedral scaffolds modified platform was reported for the detection of telomerase activity.Due to the rigid three-dimensional structure,DNA tetrahedral scaffolds grafting on the electrode surface could accurately modulate the distance between CdS QDs and luminol labelled gold nanoparticles(L-Au NPs),meanwhile provide an enhanced spatial dimension and accessibility for the assembly of multiple L-Au NPs.The ECL intensities of both CdS QDs(-1.25 V vs.SCE)and luminol(+0.33 V vs.SCE)gradually increased along with the formation of multiple L-Au NPs at the vertex of DNA tetrahedral scaffolds induced by telomerase,bringing in a dual-potential ECL analysis.The proposed method showed high sensitivity for the identification of telomerase and was successfully applied for the differentiation of cancer cells from normal cells.This work suggests that DNA tetrahedral scaffolds could serve as an excellent choice for the construction of LSPR-ECL system.2.LSPR-enhanced electrochemical for precise positioning of SECMAccording to the principle that the LSPR of gold nanoparticles(Au NPs)can catalyze the electrochemical redox reaction and then enhance the electrochemical reaction current signal,in this study,we use LSPR of Au NPs to enhance the feedback current on the SECM probe in order to improve the signal to noise ratio and positioning accuracy in the negative feedback mode of the SECM.In this study,we use a laser puller to prepare a carbon ultrafine electrode with gold nanoparticles(Au NPs)deposited on the tip as a probe of the SECM,in which the ultramicro-electrode has a diameter of about 600 nm.During the operation of the negative feedback mode of SECM,we aim the laser of 532 nm at the gold nanoparticles of the tip of the SECM probe.At this time,the surface plasmon resonance effect(LSPR)is generated on the surface of the gold nanoparticles.Due to the LSPR effect,the oxidation current of the electrochemical oxidation of tri-n-propylamine(TPrA)by the SECM probe can be enhanced by 1.2 to 2 times.At this time,the background noise of the SECM remains unchanged,and the feedback current during the operation of the SECM is always magnified until the probe is almost close to the surface of the substrate,which makes the signal to noise ratio of the SECM better.In the presence of noise currents,it is possible to operate the SECM with a close proximity to the substrate and reduce the possibility of wear or even damage to the SECM probe.Our research provides a method for amplifying SECM feedback signals,which is of great significance for the development of SECM technology.