International Journal of Pharmaceutics 423 (2012) 102–107 Contents lists available at ScienceDirect International Journal of Pharmaceutics journa l h omepa g e: www.elsevier.com/locate/ijpharm Synthesis and functionalization of persistent luminescence nanoparticles with small molecules and evaluation of their targeting ability Thomas Maldiney a,b,c,d , Gerardo Byk e , Nicolas Wattier a,b,c,d , Johanne Seguin a,b,c,d , Raz Khandadash e , Michel Bessodes a,b,c,d , Cyrille Richard a,b,c,d,∗ , Daniel Scherman a,b,c,d,∗∗ a Unité de Pharmacologie Chimique et Génétique et d’Imagerie, CNRS, UMR 8151, F-75270 Paris Cedex, France b INSERM, U1022, F-75270 Paris Cedex, France c Université Paris Descartes, Sorbonne Paris Cité, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, F-75270 Cedex, France d ENSCP, Chimie Paristech, F-75231 Paris Cedex, France e Department of Chemistry, Laboratory of Nano-Biotechnology, and School of Engineering, Bar Ilan University, Ramat Gan 52900, Israel a r t i c l e i n f o Article history: Received 10 June 2011 Accepted 29 June 2011 Available online 23 July 2011 Keywords: Persistent luminescence nanoparticles Surface functionalization Binding PC-3 In vitro a b s t r a c t We have recently reported the design and use of inorganic nanoparticles with persistent luminescence properties. Such nanoparticles can be excited with a UV lamp for 2 min and emit light in the near-infrared area for dozen of minutes without any further excitation. This property is of particular interest for small animal optical imaging, since it avoids the autofluorescence of endogenous fluorophores which is one major problem encountered when using fluorescent probes. We report herein the synthesis of persistent luminescence nanoparticles (PLNPs) and their functionalization with two small targeting molecules: biotin and Rak-2. We provide characterization of each PLNP as well as preliminary evidence of the ability of PLNP-PEG-Biotin to target streptavidin and PLNP-PEG-Rak-2 to bind prostate cancer cells in vitro. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Optical imaging techniques provide great potential for under- standing biological processes at the molecular level and for sensitive cancer diagnosis, particularly at the early stage of can- cer development (Bruchez et al., 1998). Biological optical imaging greatly relies upon the use of sensitive and stable optical labels. So far, organic dyes (Kogure et al., 2006), quantum dots (Chan and Nie, 1998; Gao et al., 2004; Michalet et al., 2005; Maysinger et al., 2007) and metal nanoparticles (Storhoff et al., 1998; Taton et al., 2000) are the most commonly used optical labels but still have some limitations. When used in vivo, fluorescent probes present numerous drawbacks (Ntziachristos, 2006) such as autofluores- cence (Frangioni, 2003) coming from tissue organic components during probe illumination. In addition, deep tissue imaging is diffi- cult because of critical absorption from major components present in living organism (water, melanin, haemoglobin, lipids). ∗ Corresponding author at: INSERM, U1022, CNRS, UMR 8151, Unité de Pharma- cologie Chimique et Génétique et d’Imagerie, Faculté de Pharmacie, 4 avenue de l’Observatoire, 75006 Paris, France. Tel.: +33 1 53 73 95 67; fax: +33 1 43 26 69 18. ∗∗ Corresponding author at: INSERM, U1022, CNRS, UMR 8151, Unité de Pharma- cologie Chimique et Génétique et d’Imagerie, Faculté de Pharmacie, 4 avenue de l’Observatoire, 75006 Paris, France. E-mail addresses: cyrille.richard@parisdescartes.fr (C. Richard), daniel.scherman@parisdescartes.fr (D. Scherman). To overcome these difficulties, we have recently developed inorganic persistent luminescence nanoparticles (PLNPs). The key element of this technology is based on long lasting luminescent nanoparticles which can be optically excited with a UV lamp before emitting in near-infrared range (le Masne de Chermont et al., 2007). The persistent luminescence is still detectable after 1 h. Among the different nanomaterials synthesized, we have shown that the com- position Ca 0.2 Zn 0.9 Mg 0.9 Si 2 O 6 doped with luminescent ions (0.5% Eu 2+ , 1% Dy 3+ and 2.5% Mn 2+ ) was the best candidate for in vivo imaging (le Masne de Chermont et al., 2009). Neutral PLNP func- tionalized with a polyoxyethylene chain (PEG) could circulate in the blood for more than 30 min if injected i.v. 5 min after the preinjection of a negative liposome used the saturate the reticulo- endothelial system (Kamps et al., 1999). Malignant tumours display both increased angiogenesis and chaotic microenvironment growth, mainly responsible for hyper vascularization, leaky vasculature, and poor lymphatic drainage (Maeda et al., 2000; Brannon-Peppas and Blanchette, 2004). It has been reported that long-circulating nanoparticles with PEG mod- ifications on their surface were able to favour passive tumour targeting (Moghimi et al., 2001; Greenwald, 2001). Injection of our PEG-PLNP to C57BL/6 mouse bearing an s.c. implanted Lewis lung carcinoma (3LL) tumour in the inguinal region, allowed us to detect the tumour vasculature during the first 2 min following the injec- tion. However no passive accumulation of our PLNP-PEG could be observed at longer time. In order to favour a passive accumulation 0378-5173/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.ijpharm.2011.06.048