120th General Meeting of the KCS

Type Oral Presentation
Area Oral Presentation of Young Analytical Chemists I
Room No. Room C311+C312
Time THU 09:40-:
Code ANAL1.O-13
Subject Effect of Adsorbate Electrophilicity and Spiky Uneven Surfaces on Single Gold Nanourchin-based Localized Surface Plasmon Resonance Sensors
Authors geunwan kim, JI WON HA*
Department of Chemistry, University of Ulsan, Korea
Abstract We present single particle studies on urchin-shaped gold nanoparticles for their use as localized surface plasmon resonance (LSPR) biosensors under dark-field (DF) microscopy. First, the LSPR wavelength of single gold nanourchins (AuNUs) was red-shifted as thiol molecules were attached onto the surface. AuNUs with sharp tips showed higher sensitivity for detecting thiol molecules than gold nanospheres (AuNSs) of similar size. Second, the degree of red shift was strongly affected by the electrophilicity of adsorbate molecules on the nanoparticle surface. Single AuNUs capped with 4-nitrothiophenol (4-NTP) strong electron withdrawing groups (EWG) caused a larger red shift than those coated with 4-aminothiophenol (4-ATP) strong electron donating groups (EDG). Last, real-time monitoring of molecular binding events on single AuNUs was performed. The LSPR peak was red-shifted and saturated after introducing 1 μM of 4-aminothiophenol. Therefore, single AuNUs were highly sensitive to changes in medium dielectric constant as well as the electrophilicity of attached thiol molecules. The results indicate that single AuNUs with sharp tips can be used to develop highly sensitive LSPR biosensors.
E-mail geunwan2@naver.com