Magnetic Extraction of Acinetobacter baumannii Using Colistin-Functionalized γ-Fe₂O₃/Au Core/Shell Composite Nanoclusters

Abstract

Acinetobacter baumannii is a Gram-negative bacterium of increasing concern due to its virulence and persistence in combat and healthcare environments. The incidence of both community-acquired and nosocomial A. baumannii infections is on the rise in foreign and domestic healthcare facilities. Treatment options are limited due to the acquisition of multidrug resistance to the few effective antibiotics. Currently, the most effective pharmaceutically based treatment for multidrug-resistant A. baumannii infections is the antibiotic colistin (polymyxin E). To minimize side effects associated with administration of colistin or other toxic antimicrobial agents, we propose the development of a nanotechnology-mediated treatment strategy. In this design-based effort, colistin-functionalized multilayered, inorganic, magnetoplasmonic nanoconstructs were fabricated to bind to the surface of A. baumannii. This result, for the first time, demonstrates a robust, pharmaceutical-based motif for high affinity, composite nanoparticulates targeting the A. baumannii surface. The antibiotic-activated nanomaterials demonstrated cytocompatibility with human cells and no acute bacterial toxicity at nanoparticle to bacterial concentrations <10 000:1. The magnetomotive characteristics of the nanomaterial enabled magnetic extraction of the bacteria. In a macroscale environment, maximal separation efficiencies exceeding 38% were achieved. This result demonstrates the potential for implementation of this technology into micro- or mesofluidic-based separation environments to enhance extraction efficiencies. The future development of such a mesofluidic-based, nanotechnology-mediated platform is potentially suitable for adjuvant therapies to assist in the treatment of sepsis.

Synthesis and Characterization of Colistin-Functionalized Silica Materials for Rapid Capture of Bacteria in Water

“…The potential application of these CST-modified nanoparticles for the sensitive detection of E . coli bacterial cells was demonstrated [ 21 ]. In another study, CST was conjugated to ortho-pyridine disulfide and an N-hydroxysuccinimide heterobifunctional polyethylene glycol polymer linker, and then superparamagnetic FeOx/Au core/shell nanoparticles were functionalized with the CST-modified conjugates.…”

“…coli [ 20 ]. Bell et al extracted A. baumannii by preparing CST-functionalized γFe 2 O 3 /Au core/shell magnetic nanoclusters [ 21 ]. These different magnetic nanoparticles were used to extract and detect bacteria from blood [ 17 ], drinking water [ 22 ], chicken meat supernatants [ 23 ], lake water, urine, etc.…”

Advances in magnetic nanoparticles for the separation of foodborne pathogens: Recognition, separation strategy, and application

“…Bell et al. (2017) modified polymyxin on the surface of MNPs and captured Acinetobacter baumannii by electrostatic interaction between colistin and the outer membrane of Gram‐negative bacteria, achieving a capture efficiency of more than 38% (Bell et al., 2017). Bai et al.…”

Harnessing the Intriguing Properties of Magnetic Nanoparticles to Detect and Treat Bacterial Infections

“…In order to overcome the shortcomings of traditional antibacterial treatment and detection methods, various metals and metal oxide nanoparticles have been used for bacterial detection and treatment [7]. MNPs have been widely used in the biological field in recent years due to their physical properties, good biocompatibility, and high binding capacity [8][9][10], including in vivo and in vitro bacterial detection and separation imaging [11], as well as the treatment of pathogenic bacteria. For example, magnetic materials were used to synthesize new structures [12] and new magnetic material composite nanoparticles with improved structural stability [13], biological activity [14], and antibacterial properties [15][16][17][18] to realize the separability and recyclability of MNPs [19][20][21].…”