Homologous Gold Nanoparticles and Nanoclusters Composites with Enhanced Surface Raman Scattering and Metal Fluorescence for Cancer Imaging.

Xiaoxia Wu,Jinze Lan,Yan Peng,Lingyan Yang,Fu Wang,Xiaomei Duan

doi:10.3390/nano8100819

Abstract

A large number of deaths from cancer can be attributed to the lack of effective early-stage diagnostic techniques. Thus, accurate and effective early diagnosis is a major research goal worldwide. With the unique phenomenon of localized surface plasmon resonance (LSPR), plasmonic nanomaterials have attracted considerable attention for applications in surface-enhanced Raman scattering (SERS) and metal-enhanced fluorescence (MEF). Both SERS and MEF are ultra-sensitive methods for the detection and identification of early tumor at molecular level. To combine the merits of the fast and accurate imaging of MEF and the stable and clear imaging of SERS, we propose a novel dual functional imaging nanoprobe based on gold nanoparticles and gold nanocluster composites (denoted AuNPC-RGD). The gold nanoparticles are used as LSPR substrates to realized enhancement of Raman or fluorescence signal, while the gold nanoclusters serve as a fluorophore for MEF imaging, and exhibit better biocompatibility and stability. Furthermore, target molecule of cyclic Arg-Gly-Asp (cRGD) is incorporated into the composite to improve delivery efficiency, selectivity and imaging accuracy. These integrated properties endow AuNPC-RGD composites with outstanding biocompatibility and excellent imaging abilities, which could be used to achieve accurate and effective diagnosis for early cancer.

Highlights

Cancer has become one of the most serious causes of disease-related death, accounting for about 15% of total human deaths every year [1,2,3,4]
To combine the merits of the fast and accurate imaging of metal-enhanced fluorescence (MEF) and the stable and clear imaging of surface-enhanced Raman scattering (SERS), we propose a novel dual functional imaging nanoprobe based on gold nanoparticles and gold nanocluster composites
The gold nanoparticles are used as localized surface plasmon resonance (LSPR) substrates to realized enhancement of Raman or fluorescence signal, while the gold nanoclusters serve as a fluorophore for MEF imaging, and exhibit better biocompatibility and stability

Summary

Introduction

Cancer has become one of the most serious causes of disease-related death, accounting for about 15% of total human deaths every year [1,2,3,4]. The organic fluorophores are relatively unstable against photobleaching and can be degraded in microenvironments To achieve both more stable and faster imaging, one highly effective strategy is to combine SERS and MEF to construct a dual functional probe, which would obtain ultrahigh-resolution imaging in a short time, and maintain image stability in the long term. The conjugation of the probe with the target molecule, cRGD, improves the delivery efficiency of the latter and the selectivity and imaging accuracy With these integrated properties, AuNPC-RGD is a novel dual functional imaging agent with outstanding stability and biocompatibility, and excellent SERS and MEF imaging efficiency, capabilities that are urgently needed for early cancer diagnosis and imaging

Materials

Synthesis of the AuNP-MBA

Conjugation of Targeted Molecule cRGD

Characterization

Biocompatibility and Cellular Uptake of Nanoparticles

Results and Discussion