RESEARCH PAPER Magnetic Nanoparticles Enhance Adenovirus Transduction In Vitro and In Vivo Cédric Sapet & Christophe Pellegrino & Nicolas Laurent & Flavie Sicard & Olivier Zelphati Received: 1 August 2011 / Accepted: 16 November 2011 / Published online: 7 December 2011 # Springer Science+Business Media, LLC 2011 ABSTRACT Purpose Adenoviruses are among the most powerful gene delivery systems. Even if they present low potential for onco- genesis, there is still a need for minimizing widespread delivery to avoid deleterious reactions. In this study, we investigated Magnetofection efficiency to concentrate and guide vectors for an improved targeted delivery. Method Magnetic nanoparticles formulations were complexed to a replication defective Adenovirus and were used to transduce cells both in vitro and in vivo. A new integrated magnetic procedure for cell sorting and genetic modification (i-MICST) was also investigated. Results Magnetic nanoparticles enhanced viral transduction effi- ciency and protein expression in a dose-dependent manner. They accelerated the transduction kinetics and allowed non-permissive cells infection. Magnetofection greatly improved adenovirus- mediated DNA delivery in vivo and provided a magnetic targeting. The i-MICST results established the efficiency of magnetic nano- particles assisted viral transduction within cell sorting columns. Conclusion The results showed that the combination of Mag- netofection and Adenoviruses represents a promising strategy for gene therapy. Recently, a new integrated method to com- bine clinically approved magnetic cell isolation devices and genetic modification was developed. In this study, we validated that magnetic cell separation and adenoviral transduction can be accomplished in one reliable integrated and safe system. KEY WORDS AdenoMag . adenovirus . in vivo transduction . magnetic cell sorting . magnetofection INTRODUCTION Since their discovery, more than 50 different serotypes of human adenoviruses (Ads) have been isolated. The Adenovir- idae family further comprises multiple non-human serotypes (1). Historically, Ads are among the first viral gene vector systems to be developed, and are now routinely used for in vitro and in vivo gene delivery (2). Among their advantages, the up-to-37 kb high cloning capacity and the ability to transduce both quiescent and dividing cells are the two main factors making Ads the vectors of choice for gene delivery applications (3). Furthermore, Ads generally present a low potential for oncogenesis as they do not insert their genome into the host DNA, as opposed to retro- or lentiviral vectors for instance (4). Because of their beneficial features, these viruses are used in one-quarter of all gene therapy trials (http://www.wiley.co.uk/genetherapy/clinical). However, clinical use of Ads in combination with systemic, non localized administration is hampered by adverse reactions, including thrombocytopenia (5), acquired immune response mediated by cytotoxic T lymphocytes against viral and/or transgene products (6) and a potentially life-threatening systemic cyto- kine syndrome due to activation of innate immunity (7). In addition, the limited ability to confine the vector to its site of action and prevent its spreading to non-target tissues also contributes to compromised therapeutic efficiency. Other limitations include therapeutically suboptimal transduction levels in cell types deficient in Coxsackie-Ads receptor (CAR) (8,9). Indeed, adenoviral transduction efficiency is highly dependent upon the expression level of CAR on the target cell surface (10) : low CAR expression levels result in low concentration of Ads on the cell surface, which decreases its gene expression efficiency. Therefore, even if C. Sapet (*) : N. Laurent : F. Sicard : O. Zelphati (*) OZ Biosciences, Parc Scientifique de Luminy 163 Avenue de Luminy case 922 13288 Marseille cedex 9, France e-mail: csapet@ozbiosciences.com e-mail: ozelphati@ozbiosciences.com C. Pellegrino INSERM UMR S901, Institut de Neurobiologie de la Méditerranée (INMED), Parc Scientifique de Luminy 163 route de Luminy - BP13 13273 Marseille cedex 09, France Pharm Res (2012) 29:1203–1218 DOI 10.1007/s11095-011-0629-9