Hindawi Publishing Corporation Journal of Nanomaterials Volume 2014, Article ID 978284, 7 pages http://dx.doi.org/10.1155/2014/978284 Research Article Development of Antibody-Coated Magnetite Nanoparticles for Biomarker Immobilization Christian Chapa Gonzalez, 1 Carlos A. Martínez Pérez, 1 Alejandro Martínez Martínez, 1 Imelda Olivas Armendáriz, 1 Oscar Zavala Tapia, 1 and Perla E. García-Casillas 1,2 1 Universidad Aut´ onoma de Ciudad Ju´ arez, Avenida del Charro 610 Norte, Colonia Partido Romero, 32315 Ciudad Ju´ arez, CHIH, Mexico 2 Universidad Aut´ onoma de Ciudad Ju´ arez, Instituto de Ingenier´ ıa y Tecnolog´ ıa, Avenida del Charro 610 Norte, Colonia Partido Romero, 32315, Ciudad Ju´ arez, CHIH, Mexico Correspondence should be addressed to Perla E. Garc´ ıa-Casillas; perlaelviagarcia@yahoo.com Received 2 September 2013; Accepted 21 January 2014 Academic Editor: Chih-Hung Hsiao Copyright © 2014 Christian Chapa Gonzalez et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Magnetic nanoparticles (MNPs) have great potential in biomedical applications because of their magnetic response ofers the possibility to direct them to speciic areas and target biological entities. Magnetic separation of biomolecules is one of the most important applications of MNPs because their versatility in detecting cancer biomarkers. However, the efectiveness of this method depends on many factors, including the type of functionalization onto MNPs. herefore, in this study, magnetite nanoparticles have been developed in order to separate the 5  -nucleotidase enzyme (5eNT). he 5eNT is used as a bio-indicator for diagnosing diseases such as hepatic ischaemia, liver tumor, and hepatotoxic drugs damage. Magnetic nanoparticles were covered in a core/shell type with silica, aminosilane, and a double shell of silica-aminosilane. A ScFv (fragment antibody) and anti-CD73 antibody were attached to the coated nanoparticles in order to separate the enzyme. he magnetic separation of this enzyme with fragment antibody was found to be 28% higher than anti-CD73 antibody and the enzyme adsorption was improved with the double shell due to the increased length of the polymeric chain. Magnetite nanoparticles with a double shell (silica-aminosilane) were also found to be more sensitive than magnetite with a single shell in the detection of biomarkers. 1. Introduction 1 Nanomedicine is generally deined as the biomedical appli- cation of nanotechnology. Nanomagnetism is at the forefront of the nanosciences as magnetic nanomaterials are the most promising materials used in the clinical diagnosis and in various therapeutic applications [1, 2]. Magnetic particles have special features that make them viable for biomedical applications [3]. heir particle size can be controlled in the nanometric scale and they can be functionalized with biocompatible molecules to interact with biological entities. Many researchers have been focusing on the nanoscale because magnetic nanoparticles contain a simple magnetic domain and show a superparamagnetic behavior at room temperature, which means that the magnetization  is close to zero in the absence of a magnetic ield, but when an external magnetic ield is applied, the magnetic moments are aligned with the ield [4]. his kind of magnetic response is highly desired in biomedical applications because these materials ofer the possibility of being manipulated to a speciic body area and target biological entities through an external stimulus. his ability of magnetic nanoparticles has allowed them to be used for labeling and manipulating biomolecules as drugs and genes [5–8]. Drug delivery is the most studied application of the magnetic nanoparticles in order to develop a new therapeutic method that increases the efectiveness of anticancer drug [9]. Magnetic drug targeting (MDT) has also been used to improve localized drug delivery to interstitial tumor targets. MDT involves attaching an antibody to the nanoparticles surface in order to get an antibody-antigen coupling ensuring an eicient and controlled drug release [10]. In order to improve the