%0 Journal Article %T Development of Magnetic Nanoparticles for Cancer Gene Therapy: A Comprehensive Review %A Vladimir Mulens %A Mar¨ªa del Puerto Morales %A Domingo F. Barber %J ISRN Nanomaterials %D 2013 %R 10.1155/2013/646284 %X Since they were first proposed as nonviral transfection agents for their gene-carrying capacity, magnetic nanoparticles have been studied thoroughly, both in vitro and in vivo. Great effort has been made to manufacture biocompatible magnetic nanoparticles for use in the theragnosis of cancer and other diseases. Here we survey recent advances in the study of magnetic nanoparticles, as well as the polymers and other coating layers currently available for gene therapy, their synthesis, and bioconjugation processes. In addition, we review several gene therapy models based on magnetic nanoparticles. 1. Introduction 1.1. Cancer & Current Therapy Although huge efforts have led to advances in cancer treatment, this multifactorial and heterogeneous disease is still one of the major causes of death in the majority of countries [1¨C4]. Several factors influence the high death rate of cancer patients around the world, such as the genetic and phenotypic heterogeneity and the highly unstable genome of cancer cells, which ultimately leads to continuously emerging, nonheterogeneous cells from the tumor nest, and subsequent metastases [5]. Current cancer therapy encompasses a wide variety of treatments from systemic cytostatics to targeted therapy agents, most still in development phases, such as kinase inhibitors [6¨C9], antibodies [10, 11], small molecules, or cell- and antigen-based immunotherapies [12, 13]. Nevertheless, most approved therapeutics require systemic administration, which increases their toxicity and other clinical complications. One factor that eventually contributes to therapeutic toxicity is nonspecificity. Guidance of drugs to the desired tissue and specific target recognition are therefore major concerns faced by cancer researchers seeking less toxic side effects and improved efficiency of therapy. Targeted strategies include ligand-receptor binding, antibody-antigen specificity, and some other forms of active targeting. For instance, several antibodies have been developed that are directed to specific tumor-associated antigens, either expressed uniquely by tumor cells or overexpressed compared with healthy tissue; this is the case of the HER2-specific antibody Herceptin [10], the VEGF-specific antibody Bevacizumab [11], and ganglioside-specific antibodies such as 14F7 [14]. Nanotechnology, and in particular a magnetic nanoparticle-based approach, is a promising tool for the guidance of therapeutic agents into tumor tissues. 1.2. Nanotechnology in Cancer Theragnosis Use of nanotechnology is widespread in several fields of biomedicine due to its %U http://www.hindawi.com/journals/isrn.nanomaterials/2013/646284/