SERS Study of Tetrodotoxin (TTX) by Using Silver Nanoparticle Arrays

Abstract

The optical properties of tetrodotoxin (TTX), a scarce toxin with anesthetic properties, were studied using nanoparticle arrays-assisted surface-enhanced Raman scattering (SERS). The nanoparticles arrays were fabricated using nanosphere lithography and a metallic lift-off process to control the particle size, shape, and spacing in the arrays. Using density functional methods, the Raman spectrum of TTX was also calculated with Gaussian03 software. The main peaks of the spectrum are originated from the vibration of the NH 2 molecule group. In the SERS experiment, we were able to measure the Raman spectrum with a TTX concentration as less as 0.9 ng/mL. This sensitivity is comparable to that from high performance liquid chromatography.

Review of Experimental Setups for Plasmonic Photocatalytic Reactions

“…Plasmons are collective oscillations of free electrons at a metal-dielectric interface and are induced by external electromagnetic waves [26,27]. In general, plasmons can be roughly categorized into three types; i.e., VPs, SPs, and LSPs.…”

“…For large-scale material sensing or photocatalytic reactions, array or condensed random structures can achieve relatively high light absorption [141][142][143] or can even be perfect absorbers [144,145]. Furthermore, array structures help in SERS [26,27] and ultrafast real-time bioassays [140]. Metallic or heterostructure materials can facilitate the achievement of multilevel [146] and recyclable functions [147], respectively.…”

Lithographied nanostructures as nanosensors

“…Lin et al succeeded in the detection of the tetrodotoxin (scarce toxin with anesthesic properties) on equivalent arrays (nanoparticles size of 100 nm and 120 nm in height) and reached a LOD of 10 −9 mol∕L. 140 In the case of MFON substrates, 10 −4 M BPE has been used as test molecule to evaluate the EF: nanospheres with a diameter of 542 nm and silver thickness of 200 nm have an average EF of 10 7 . The random structure roughness that support LSPR contributed for 10 5 to this enhancement and delocalized SP contributed for 10 2 .…”

Fabrication and Characterization of a Metallic–Dielectric Nanorod Array by Nanosphere Lithography for Plasmonic Sensing Application

“…Plasmon resonances occur, and these resonances are dependent on the geometrical structures of the metal nanostructures, like the localized surface plasmon resonance (SPR) and gap plasmon resonance (GPR) of metallic nanorods [1][2][3][4]. Studies have reported the potential use of these resonances, e.g., plasmonic sensors [5,6], infrared band filters [7,8], surface-enhanced Raman scattering (SERS) substrates [9,10], and heat radiation/absorption manipulation [11]. The advances in nanofabrication technologies [12,13] have a significant impact in promoting the use of plasmonic nanorod arrays as SPR sensors [14][15][16][17].…”