title: Highly luminescent and nontoxic amine-capped nanoparticles from porous silicon: synthesis and their use in biomedical imaging.
abstract: Stable and brightly luminescent amine-terminated Si nanoparticles (SiNPs) have been synthesized from electrochemically etched porous silicon (PSi). The surface amine termination was confirmed by FTIR, NMR, and XPS studies. The mean diameter of the crystal core of 4.6 nm was measured by transmission electron microscopy (TEM), which is in a good agreement with the size obtained by dynamic light scattering (DLS). The dry, amine-terminated product can be obtained from bulk silicon wafers in less than 4 h. This represents a significant improvement over similar routines using PSi where times of >10 h are common. The emission quantum yield was found to be about 22% and the nanoparticles exhibited an exceptional stability over a wide pH range (4-14). They are resistant to aging over several weeks. The amine-terminated SiNPs showed no significant cytotoxic effects toward HepG2 cells, as assessed with MTT assays.
authors.affiliation: Energy Materials Laboratory, School of Chemistry, University of East Anglia , Norwich NR4 7TJ, United Kingdom.
authors.forename: Jayshree H
authors.initials: JH
authors.lastname: Ahire
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Paul R
authors.initials: PR
authors.lastname: Coxon
authors.forename: Girish
authors.initials: G
authors.lastname: Malhotra
authors.forename: Rik
authors.initials: R
authors.lastname: Brydson
authors.forename: Rongjun
authors.initials: R
authors.lastname: Chen
authors.forename: Yimin
authors.initials: Y
authors.lastname: Chao
mesh_terms: D000588:Amines / Q000737:chemistry*; D002470:Cell Survival / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D018613:Microscopy, Confocal; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D016062:Porosity; D012825:Silicon / Q000737:chemistry*
chemical_list: D000588:Amines; D012825:Silicon