Recent Advances in Synthesis and Biomedical Applications of Magnetic Nanoparticles: Magnetic Nanoparticles for Biomedical Applications

Introduction

Nanotechnology is now a days working at the cellular and molecular levels to produce major progress in the life sciences and healthcare. Although real applications of nanomaterials in life sciences are still uncommon but the excellent properties of these materials provide a very promising future for their use in this field (Grainger & Okano, 2003; Hood et al., 2002; Niemeyer, 2001). Nanoclusters located at the transition region between molecules and micron size particles are ultrafine particles of nanometer dimensions. When viewed from the molecular perspective, their particle size is so large that they provide access to realms of quantum behaviour which are not otherwise accessible and from the materials perspective, their particle size is so small that they exhibit characteristics not observed in the larger structures (>100 nm). Recent advances in biology, physics and chemistry has been mainly made in this size regime (Roco, Williams, & Alivisatos, 2000). For example, the band gap of semiconductor material increases when the particle dimension of semiconductor materials become comparable to, or smaller than the Bohr radius (El-Sayed, 2001; Heath, 1995). In noble metals, intense absorption is observed in the visible to near UV region as the particle size decreases below the electron mean free path (Bohren & Huffman, 1983). Other fascinating mechanical behaviors such as superplasticity is also observed in metal nanoparticles in this size range (Kung & Foecke, 1999). Powder ceramic materials with particle size in nanorange are also receiving attention due to significant enhancement in the sintering rates or lowering of sintering temperatures (Hahn, Logas, & Averback, 1990; J. Tartaj, Zärate, Tartaj, & Lachowski, 2002; P Tartaj & Tartaj, 2002). Ceramic matrix composites with dispersed nanoparticles have better mechanical properties (Kung & Foecke, 1999; Niihara, 1991; a G. Roca et al., 2009).

Nanotechnology has made major contribution in medicine and pharmaceutical industries, like controlled drug delivery, as biosensors, in disease detection, in tissue engineering etc. However, nanoparticles designed for drug delivery should be biocompatible and biodegradable (Gupta & Gupta, 2005a; Xie et al., 2006). Among many other nanosystems, special interest is focused on magnetic nanoparticles (MNPs), which have a potential to revolutionize current clinical diagnostic and therapeutic techniques (Mailander & Landfester, 2009; Mishra, Patel, & Tiwari, 2010; Suh, Suslick, Stucky, & Suh, 2009). Many applications of MNPs have been widely studied including magnetically induced hyperthermia, magnetically enhanced transfection, magnetically assisted gene therapy and magnetic-force-based tissue engineering (Chomoucka et al., 2010; Corchero & Villaverde, 2009).

However, the development of highly effective medicine requires continuous and timely monitoring of the medical treatment process. This monitoring in combination with therapeutics commonly referred to as “theranostics” allows a large degree of control on the treatment efficacy in different individuals (Sambasivarao, 2013). Magnetic nanoparticles (MNPs) containing ferromagnetic iron (Fe) and cobalt (Co) as well as their alloys and oxides has proved to be the most promising probes for theranostics with therapeutic efficacy and desired imaging sensitivity (J. Kim, Piao, & Hyeon, 2009; Lacroix, Ho, & Sun, 2010; Sambasivarao, 2013).