title: Direct surface modification of ligand-free silicon quantum dots prepared by femtosecond laser ablation in deionized water.
abstract: Amine-terminated, ultra-small silicon nanoparticles (Si-NPs) were prepared in one step avoiding the conventional chemical or thermal treatment of Si surface, by introducing organosilane in Si-NPs colloidal solution freshly prepared by ultra-fast laser ablation of silicon target in deionized water. Surface chemistry studies of Si-NPs conducted by Raman and Fourier infrared spectroscopy demonstrated the hydroxyl-terminated surface of Si-NPs. The reactivity of hydroxyl-terminated surface with aminopropyltriethoxysilane in aqueous solution was investigated. Electron microscopy, dynamic light scattering, infrared spectroscopy and stability studies confirmed the successful functionalization of Si-NPs leading to 5nm Si dots covered by aminopropyltriethoxysilane thick layer. Detailed infrared spectroscopy analysis of the Si-O-Si region as a function of immersion time revealed the formation of interfacial Si-O bonds between the organosilane and hydroxyl groups of the nanoparticles. The biocompatible Si nanostructure containing amine functional group prepared using a one-step green protocol opens the route for biomedical applications and successful translation into clinical setting, as bio-labels, contrast agents and vector delivery.
authors.affiliation: Nanophysics, Istituto Italiano di Tecnologia, Via Morego, 30, 16163 Genova, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Rodio
authors.affiliation: Nanochemistry, Istituto Italiano di Tecnologia, Via Morego, 30, 16163 Genova, Italy.
authors.forename: Rosaria
authors.initials: R
authors.lastname: Brescia
authors.affiliation: Nanophysics, Istituto Italiano di Tecnologia, Via Morego, 30, 16163 Genova, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Diaspro
authors.affiliation: Nanophysics, Istituto Italiano di Tecnologia, Via Morego, 30, 16163 Genova, Italy. Electronic address: romuald.intartaglia@iit.it.
authors.forename: Romuald
authors.initials: R
authors.lastname: Intartaglia
keywords: Biomedical; Functionalization; Green synthesis; Infrared spectroscopy; Laser ablation; Laser processing; Nanoparticles; Quantum dots; Silicon; Surface modification