β-Carotene doped silica nanoparticles as a novel resonance Raman scattering tag for in vivo cellular imaging

In the present study, silica nanoparticles with resonance Raman scattering (RRS) properties were utilized to construct a novel resonance Raman scattering tag for in vivo cellular imaging. β-Carotene, a native pigment insoluble in water, was for the first time encapsulated in silica nanoparticles through a simple one-step procedure in which β-carotene was enriched in the micelle of cetyltrimethylammonium bromide (CTAB) and simultaneously enclosed during the hydrolysis of tetraethylorthosilicate (TEOS). The particles were characterized by using X-ray diffraction, transmission electron microscopy (TEM), and Raman spectroscopy. Results showed that the size distribution of β-carotene doped silica nanoparticles (CSNPs), which were highly dispersible in aqueous solution, was fairly uniform in the range of 60 to 200 nm. Due to the advantages of highly stable and repeatable RRS signals of doped β-carotene, a simple cellular imaging approach based on this novel Raman tag has been preliminarily achieved. This paper demonstrated that resonance Raman scattering tags are important candidates for biological applications considering their high biocompatibility and spectral stability.