Synthesis and characterisation of highly fluorescent core–shell nanoparticles based on Alexa dyes
- 672 Downloads
Current and future developments in the emerging field of nanobiotechnology are closely linked to the rational design of novel fluorescent nanomaterials, e.g. for biosensing and imaging applications. Here, the synthesis of bright near infrared (NIR)-emissive nanoparticles based on the grafting of silica nanoparticles (SNPs) with 3-aminopropyl triethoxysilane (APTES) followed by covalent attachment of Alexa dyes and their subsequent shielding by an additional silica shell are presented. These nanoparticles were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence spectroscopy. TEM studies revealed the monodispersity of the initially prepared and fluorophore-labelled silica particles and the subsequent formation of raspberry-like structures after addition of a silica precursor. Measurements of absolute fluorescence quantum yields of these scattering particle suspensions with an integrating sphere setup demonstrated the influence of dye labelling density-dependent fluorophore aggregation on the signaling behaviour of such nanoparticles.
KeywordsSilica Alexa dyes Fluorescent particles Quantum yields Nanoparticles Protective shell Nanobiotechnology
This study has been supported by the Federal Institute for Materials Research and Testing (BAM) within the framework of its ‘Innovationsoffensive’ under the Project name ‘Nanotox’ and by the Federal Ministry of Economics and Technology (BMWI-22/06). The authors also thank G. Hidde and I. Dörfel for excellent technical and analytical assistance.
- Benezra M, Penate-Medina O, Zanzonico BP, Schaer D, Ow H, Burns A, DeStanchina E, Longo V, Herz E, Iyer S, Wolchok J, Larson MS, Wiesner U, Bradbury SM (2011) Multimodal silica nanoparticles are effective cancer-targeted probes in a model of human melanoma. J Clin Invest 121:2768–2780CrossRefGoogle Scholar
- Bergna HE, Roberts OW (2006) Colloidal Silica: fundamentals and applications CRC Press. Taylor & Francis Group: Boca Raton 131:895Google Scholar
- Berlier JE, Rothe A, Buller G, Bradford J, Gray DR, Filanosk BJ, Telford WG, Yue S, Liu J, Cheung C-Y, Chang W, Hirsch JD, Beechem JM, Haugland RP, Haugland RP (2003) Quantitative comparison of long-wavelength Alexa Fluor dyes to Cy dyes: fluorescence of the dyes and their bioconjugates. Journal of Histochemistry & Cytochemistry 51(12):1179–1188CrossRefGoogle Scholar
- Härmä H (2002) Particle technologies in diagnostics technology review. TEKES, National Technology Agency 126Google Scholar
- Murdock CR, Braydich-Stolle L, Schrand MA, Schlager JJ, M. Hussain MS (2008) Characterization of nanomaterial dispersion in solution prior to in vitro exposure using dynamic light scattering technique. Toxicol Sci 101:239–253Google Scholar
- Vasilis N, Christoph B, Ralph W (2003) Fluorescence imaging with near-infrared light: new technological advances that enable in vivo molecular imaging. Eur Radiol 13:195–208Google Scholar
- Würth C, Grabolle M, Pauli J, Spieles M, Resch-Genger U (2011) Comparison of methods and achievable uncertainties for the relative and absolute measurement of photoluminescence quantum yields. Anal Chem 83(9):3431–3439Google Scholar