Binding of functionalized paramagnetic nanoparticles to bacterial lipopolysaccharides and DNA.
Magnetite and metallic cobalt-based nanoparticles with sizes ranging from 10 to 300 nm and surface-functionalized with poly(hexamethylene biguanide) (PHMBG) are introduced as capable lipopolysaccharide (LPS)-sequestering agents. The nanoparticles efficiently bind to whole E. coli cells and can be used to separate the cells effectively from suspension using a magnet. A fluorescence dye displacement assay shows strong affinities of the nanoparticles for lipid A, the glycolipid component of LPS responsible for septic shock. The particle-lipid A affinity is of the same order of magnitude or higher than that of polymyxin B. The affinity of smaller (< 50 nm) magnetite particles modified with PHMBG to lipid A is several-fold higher than that of their larger counterparts (> 100 nm) due to their higher surface area to volume ratio. The nanoparticles possess high saturation capacity for double-stranded lambdaDNA from E. coli, with which particle-polyelectrolyte complexes are formed. The PHMBG-modified nanoparticles are potent bactericides, inhibiting E. coli viability and growth at concentrations at < or = 10 microg/mL.
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Lev
L
Bromberg
Emily P
EP
Chang
Carmen
C
Alvarez-Lorenzo
Beatriz
B
Magariños
Angel
A
Concheiro
T Alan
TA
Hatton
D004247:DNA / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry* / Q000254:growth & development; D005456:Fluorescent Dyes / Q000737:chemistry; D008070:Lipopolysaccharides / Q000737:chemistry*; D053758:Nanoparticles; D013050:Spectrometry, Fluorescence
D005456:Fluorescent Dyes; D008070:Lipopolysaccharides; D004247:DNA