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Gold-functionalized magnetic nanoparticles restrict growth of Pseudomonas aeruginosa.

Niemirowicz K, Swiecicka I, Wilczewska AZ, Misztalewska I, Kalska-Szostko B, Bienias K, Bucki R, Car H - Int J Nanomedicine (2014)

Bottom Line: We observed significant inhibition of P. aeruginosa growth in bacterial cultures continued over 96 hours in the presence of gold-functionalized nanoparticles (Fe₃O₄@Au).At the 48-hour time point, growth of P. aeruginosa, as assessed by the number of colonies grown from treated samples, showed the highest inhibition (decreased by 40%).These data provide strong evidence that Fe₃O₄@Au can dramatically reduce growth of P. aeruginosa and provide a platform for further study of the antibacterial activity of this nanomaterial.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiological and Nanobiomedical Engineering, Medical University of Bialystok, Bialystok, Poland ; Department of Experimental Pharmacology, Medical University of Bialystok, Bialystok, Poland.

ABSTRACT
Superparamagnetic iron oxide nanoparticles (SPIONs) and their derivatives (aminosilane and gold-coated) have been widely investigated in numerous medical applications, including their potential to act as antibacterial drug carriers that may penetrate into bacteria cells and biofilm mass. Pseudomonas aeruginosa is a frequent cause of infection in hospitalized patients, and significant numbers of currently isolated clinical strains are resistant to standard antibiotic therapy. Here we describe the impact of three types of SPIONs on the growth of P. aeruginosa during long-term bacterial culture. Their size, structure, and physicochemical properties were determined using transmission electron microscopy, X-ray diffraction analysis, and Fourier transform infrared spectroscopy. We observed significant inhibition of P. aeruginosa growth in bacterial cultures continued over 96 hours in the presence of gold-functionalized nanoparticles (Fe₃O₄@Au). At the 48-hour time point, growth of P. aeruginosa, as assessed by the number of colonies grown from treated samples, showed the highest inhibition (decreased by 40%). These data provide strong evidence that Fe₃O₄@Au can dramatically reduce growth of P. aeruginosa and provide a platform for further study of the antibacterial activity of this nanomaterial.

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Energy-dispersive X-ray spectra of Fe3O4 nanoparticles functionalized with aminosilane (Fe3O4@NH2) (A) and with gold (Fe3O4@Au) (B).
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f3-ijn-9-2217: Energy-dispersive X-ray spectra of Fe3O4 nanoparticles functionalized with aminosilane (Fe3O4@NH2) (A) and with gold (Fe3O4@Au) (B).

Mentions: A comparison of the Fourier transform infrared spectra for solid samples of aminosilane and gold-functionalized nanoparticles and the uncoated controls is shown in Figure 1. TEM-based techniques were used to evaluate the size and the shape of the nanoparticles. The TEM images were measured at high magnification. The particles were found to be spherical, with an estimated average size of 9 nm, 10 nm, and 13 nm for Fe3O4, Fe3O4@NH2, and Fe3O4@Au, respectively. The TEM images and histograms showing the size distribution of the magnetic nanoparticles are presented in Figure 2. The silica and gold coating around the magnetic core can be observed on the TEM images as obtained from 3-aminopropyltrimethoxsilane and gold chlorideused during synthesis. The ratios of elements in the modified Fe3O4 nanoparticles were characterized by energy-dispersive X-ray and TEM analysis, and are shown for Fe3O4@NH2 and Fe3O4@Au in Tables 1 and 2, respectively. Energy-dispersive X-ray spectra collected from the samples imaged by TEM clearly show the presence of a silica signal from Fe3O4@NH2 (Figure 3A) and a gold signal from Fe3O4@Au (Figure 3B). Peaks at 8 keV and 8.9 keV are attributable to the copper in the copper grid. X-ray diffractograms of the respective samples are shown in Figure 4. A similar basic set of diffraction patterns can be seen in each sample. The diffractograms typical signals (220) (311) (400) (422) (333) (440) (531) (731) appear, confirming adequate crystallinity of the unmodified nanoparticles.21 In addition, weak signals typical for hematite (012) can be observed in the nanoparticles coated with an aminosilane shell.22 For particles covered with gold, the crystalline structure of metallic gold can be observed.23 The coherent diffraction zone was calculated from the width of the X-ray diffraction peaks using the Debye-Scherrer approximation,24 and was found to be 10±2 nm, 11±2 nm, and 15±2 nm for Fe3O4, Fe3O4@NH2, and Fe3O4@Au, respectively, which is in agreement with data obtained from TEM


Gold-functionalized magnetic nanoparticles restrict growth of Pseudomonas aeruginosa.

Niemirowicz K, Swiecicka I, Wilczewska AZ, Misztalewska I, Kalska-Szostko B, Bienias K, Bucki R, Car H - Int J Nanomedicine (2014)

Energy-dispersive X-ray spectra of Fe3O4 nanoparticles functionalized with aminosilane (Fe3O4@NH2) (A) and with gold (Fe3O4@Au) (B).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4020905&req=5

f3-ijn-9-2217: Energy-dispersive X-ray spectra of Fe3O4 nanoparticles functionalized with aminosilane (Fe3O4@NH2) (A) and with gold (Fe3O4@Au) (B).
Mentions: A comparison of the Fourier transform infrared spectra for solid samples of aminosilane and gold-functionalized nanoparticles and the uncoated controls is shown in Figure 1. TEM-based techniques were used to evaluate the size and the shape of the nanoparticles. The TEM images were measured at high magnification. The particles were found to be spherical, with an estimated average size of 9 nm, 10 nm, and 13 nm for Fe3O4, Fe3O4@NH2, and Fe3O4@Au, respectively. The TEM images and histograms showing the size distribution of the magnetic nanoparticles are presented in Figure 2. The silica and gold coating around the magnetic core can be observed on the TEM images as obtained from 3-aminopropyltrimethoxsilane and gold chlorideused during synthesis. The ratios of elements in the modified Fe3O4 nanoparticles were characterized by energy-dispersive X-ray and TEM analysis, and are shown for Fe3O4@NH2 and Fe3O4@Au in Tables 1 and 2, respectively. Energy-dispersive X-ray spectra collected from the samples imaged by TEM clearly show the presence of a silica signal from Fe3O4@NH2 (Figure 3A) and a gold signal from Fe3O4@Au (Figure 3B). Peaks at 8 keV and 8.9 keV are attributable to the copper in the copper grid. X-ray diffractograms of the respective samples are shown in Figure 4. A similar basic set of diffraction patterns can be seen in each sample. The diffractograms typical signals (220) (311) (400) (422) (333) (440) (531) (731) appear, confirming adequate crystallinity of the unmodified nanoparticles.21 In addition, weak signals typical for hematite (012) can be observed in the nanoparticles coated with an aminosilane shell.22 For particles covered with gold, the crystalline structure of metallic gold can be observed.23 The coherent diffraction zone was calculated from the width of the X-ray diffraction peaks using the Debye-Scherrer approximation,24 and was found to be 10±2 nm, 11±2 nm, and 15±2 nm for Fe3O4, Fe3O4@NH2, and Fe3O4@Au, respectively, which is in agreement with data obtained from TEM

Bottom Line: We observed significant inhibition of P. aeruginosa growth in bacterial cultures continued over 96 hours in the presence of gold-functionalized nanoparticles (Fe₃O₄@Au).At the 48-hour time point, growth of P. aeruginosa, as assessed by the number of colonies grown from treated samples, showed the highest inhibition (decreased by 40%).These data provide strong evidence that Fe₃O₄@Au can dramatically reduce growth of P. aeruginosa and provide a platform for further study of the antibacterial activity of this nanomaterial.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiological and Nanobiomedical Engineering, Medical University of Bialystok, Bialystok, Poland ; Department of Experimental Pharmacology, Medical University of Bialystok, Bialystok, Poland.

ABSTRACT
Superparamagnetic iron oxide nanoparticles (SPIONs) and their derivatives (aminosilane and gold-coated) have been widely investigated in numerous medical applications, including their potential to act as antibacterial drug carriers that may penetrate into bacteria cells and biofilm mass. Pseudomonas aeruginosa is a frequent cause of infection in hospitalized patients, and significant numbers of currently isolated clinical strains are resistant to standard antibiotic therapy. Here we describe the impact of three types of SPIONs on the growth of P. aeruginosa during long-term bacterial culture. Their size, structure, and physicochemical properties were determined using transmission electron microscopy, X-ray diffraction analysis, and Fourier transform infrared spectroscopy. We observed significant inhibition of P. aeruginosa growth in bacterial cultures continued over 96 hours in the presence of gold-functionalized nanoparticles (Fe₃O₄@Au). At the 48-hour time point, growth of P. aeruginosa, as assessed by the number of colonies grown from treated samples, showed the highest inhibition (decreased by 40%). These data provide strong evidence that Fe₃O₄@Au can dramatically reduce growth of P. aeruginosa and provide a platform for further study of the antibacterial activity of this nanomaterial.

Show MeSH
Related in: MedlinePlus