Preparation and Characterization of Aminosilane-Functionalized Magnetic Antibody Conjugates for Bacterial Recognition and Capture

In this paper, we present the synthesis and characterization of antibody-conjugated aminosilane-functionalized iron oxide nanoparticles (Se-IgG-Ab-[Fe₃O₄@APTES]). Iron oxide nanoparticles are synthesized through a co-precipitation method followed by the surface modification with (3-aminopropyl)triethoxysilane (APTES) and subsequently by the bioconjugation of a specific antibody. The prepared antibody-conjugated magnetic nanomaterials were characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectra, and vibrating sample magnetometry. The Se-IgG-Ab-[Fe₃O₄@APTES] conjugates exhibited a capability to detect and capture Gram-negative bacteria, Salmonella enteritidis, at low concentration. These results suggest that the specific antibody-conjugated magnetic nanomaterials can be used as a promising platform for efficient bacterial capture and separation applications.

I. Introduction

Nowadays, worldwide, foodborne illness or food poisoning is an emerging public health problem. According to the report of the World Health Organization, there were 600 million foodborne illnesses and 420000 thousand deaths in the year 2010 [1]. Among many causes of food poisoning, bacteria are the most common pathogens (66%), followed by chemicals (26%), viruses (4%), and parasites (4%) [2]. There are some common foodborne bacterial pathogens including Campylobacter jejuni, Clostridium perfringens, Escherichia coli, Salmonella enterica (Salmonella enteritidis, Salmonella typhi, and Salmonella typhimurium), Staphylococcus aureus, Bacillus cereus, Vibrio cholerae, Shigella spp, and Listeria monocytogenes which are found in food, eggs, meat, milk, and drinks.