Platinum Nanoparticles as Photoactive Substrates for Mass Spectrometry and Spectroscopy Sensors

Abstract

Aqueous suspensions of platinum colloidal nanoparticles of varying size and polydispersity have been produced by ablation of a platinum target with a nanosecond Q-switched Nd:YAG laser. Several laser wavelengths (1064, 532 and 266 nm) and stabilizing agents (citrate and polymers PEG, PVA and PVP) were employed. Laser ablation with the infrared and visible wavelengths leads to spherical amorphous nanoparticles with a bimodal distribution of diameters, featuring a global maximum in the range 5-10 nm and a shoulder extending to 25 nm. Such bimodal distributions plausibly arise from thermal and explosive vaporization mechanisms occurring in different time scales, as proposed in earlier studies.Ultraviolet ablation of Pt at 266 nm, reported here for the first time, produces crystalline nanoparticles of small size (1-4 nm diameter), with a weak onset of larger particles (6-8 nm). The ablation at 266 nm also produced an appreciable yield of large rod-like particles of size ∼ 10 x 70 nm 2 , especially in the presence of PEG and PVA. The Pt nanoparticles served to fabricate films capable of assisting the laser desorption ionization (LDI) of a model peptide. The best analytical performance for LDI mass spectrometric detection was obtained with Pt nanoparticles surface functionalized with citrate and PVA.

Preparation of Surface-Enhanced Raman Scattering Substrates Based on Immobilized Silver-Capped Nanoparticles

“…Also, different nanoparticle functionalizations cause changes in the near-surface refractive index n that result in a shift of the absorption maximum [18]. Although these facts can be used to tune the plasmon absorption for being used in surface plasmon resonance (SPR) spectroscopy, one of the most important applications concerning this effect is surfaceenhanced Raman scattering (SERS) [19][20][21][22][23], which aims at reaching ultrasensitive detection, from simple chemical pollutants to biomolecules and immunoassays [24][25][26] with up to single-molecule sensitivity [27,28]. The reason behind this huge increment of sensitivity with respect to usual resonant Raman experiments are the increase of the molecular Raman cross section by several orders of magnitude to even 10 14 for some molecule-surface combinations [29].…”

Formation and antibacterial action of Pt and Pd nanoparticles sputtered into liquid

“…Introduction: Over the past decades, noble metal nanoparticles (NPs) have been widely studied because of their unique optical, catalytic, electromagnetic and bactericidal properties, which are strongly influenced by their shape and size. Platinum NPs (PtNPs) constitute a versatile material with a unique combination of thermal, chemical and optical plasmonic properties [1]. Besides other interesting applications, noble metal NPs (e.g.…”

Size-Controlled Synthesis of Pt Particles on TiO2 Surface: Physicochemical Characteristic and Photocatalytic Activity

“…The main localized surface plasmon resonance (LSPR) peak was found at 410 nm. An increase of absorption in the visible-near infrared region resulted from tailoring of platinum LSPR and/or electron transport from Pt II to Pt IV species [5,[30][31][32]. The highest absorption band was observed for 0.1Pt-TiO2_ST01 and 0.1Pt-TiO2_ST01_Me_3 containing small spherical nanoparticles of platinum deposited on commercial TiO2 ST01.…”