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

TY - JOUR

T1 - A Dual-Modal SERS/Fluorescence Gold Nanoparticle Probe for Mitochondrial Imaging

AU - Eling, Charlotte J.

AU - Price, Thomas W.

AU - Marshall, Addison R.L.

AU - Narda Viscomi, Francesco

AU - Robinson, Peter

AU - Firth, George

AU - Adawi, Ali M.

AU - Bouillard, Jean Sebastien G.

AU - Stasiuk, Graeme J.

PY - 2017/5/1

Y1 - 2017/5/1

N2 - A novel SERS/fluorescent multimodal imaging probe for mitochondria has been synthesised using 12 nm 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 pKa at pH 6.62, which makes it an ideal candidate for a pH-sensitive imaging probe in the biological range (pH 6.5–7.4). 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 (+18 mV) to negatively charged (−60 mV) 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.

AB - A novel SERS/fluorescent multimodal imaging probe for mitochondria has been synthesised using 12 nm 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 pKa at pH 6.62, which makes it an ideal candidate for a pH-sensitive imaging probe in the biological range (pH 6.5–7.4). 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 (+18 mV) to negatively charged (−60 mV) 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.

KW - fluorescent probes

KW - gold

KW - nanoparticles

KW - Raman spectroscopy

KW - rhodamine

UR - http://www.scopus.com/inward/record.url?scp=85011317593&partnerID=8YFLogxK

U2 - 10.1002/cplu.201600593

DO - 10.1002/cplu.201600593

M3 - Article

C2 - 31961531

AN - SCOPUS:85011317593

SN - 2192-6506

VL - 82

SP - 674

EP - 680

JO - Chempluschem

JF - Chempluschem

IS - 5

ER -