A Dual-Modal SERS/Fluorescence Gold Nanoparticle Probe for Mitochondrial Imaging

作者：Eling Charlotte J; Price Thomas W; Marshall Addison R L; Viscomi Francesco Narda; Robinson Peter; Firth George; Adawi Ali M^*; Bouillard Jean Sebastien G^*; Stasiuk Graeme J^*

来源：ChemPlusChem, 2017, 82(5): 674-680.

DOI：10.1002/cplu.201600593

• fluorescent probes
• gold
• nanoparticles
• Raman spectroscopy
• rhodamine

A novel SERS/fluorescent multimodal imaging probe for mitochondria has been synthesised using 12nm diameter gold nanoparticles (AuNP) surface functionalised with a rhodamine thiol derivative ligand. The normal pH-dependent fluorescence of the rhodamine-based ligand is inversed when it is conjugated with the AuNP and higher emission intensity is observed at basic pH. This switch correlates to a pK(a) at pH6.62, which makes it an ideal candidate for a pH-sensitive imaging probe in the biological range (pH6.5-7.4). The observed pH sensitivity of the ligand when attached to the AuNP is thought to be due to the formation of a spirolactam ring, going from positively charged (+18mV) to negatively charged (-60mV) as the pH is changed from acidic to basic. Additionally, conjugation of the ligand to the AuNP serves to enhance the Raman signal of the rhodamine ligand through surface-enhanced Raman scattering (SERS). Confocal microscopy has shown that the probe enters HEK293 (kidney), A2780 (ovarian cancer) and Min6 (pancreatic beta) cells within an hour and a half incubation time. The probe was shown to localise in the mitochondria, thus providing a novel pH-dependent SERS/fluorescent multimodal imaging probe for mitochondria.

• 出版日期2017-5