Super-paramagnetic iron oxide nanoparticles for use in extrapulmonary tuberculosis diagnosis


Corresponding author: W.-F. T. Lai, Graduate Institute of Medical Sciences, Taipei Medical University, 250 Wuhsing St., Taipei, Taiwan 110, China
Brain Imaging Center, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
E-mail: tlai@mclean.harvard.eduY. M. Wang, Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 300, Taiwan


Clin Microbiol Infect 2012; 18: E149–E157


The limited sensitivity of serological tests for mycobacterial antigens has encouraged the development of a nanoparticle probe specific for the extrapulmonary form of Mycobacterium tuberculosis (Mtb). We developed an innovative probe comprised of super-paramagnetic iron oxide (SPIO) nanoparticles conjugated with Mtb surface antibody (MtbsAb-nanoparticles) to provide ultrasensitive imaging of biomarkers involved in extrapulmonary Mtb infection. MtbsAb-nanoparticles were significantly conjugated with Mtb bacilli. The extent of contrast enhancement reduction on magnetic resonance imaging (MRI) for Mtb and human monocytic THP1 cells was proportional to the concentration of MtbsAb-nanoparticles. When MtbsAb-nanoparticles were intravenously injected into mice bearing Mtb granulomas, the granulomatous site showed a 14-fold greater reduction in signal intensity enhancement on T2-weighted MR images compared with an opposing site that received PBS injection. Mtb sAb-nanoparticles represent a new non-invasive technology for the diagnosis of extrapulmonary Mtb.