4 research outputs found
Air Stable Magnetic Bimetallic Fe–Ag Nanoparticles for Advanced Antimicrobial Treatment and Phosphorus Removal
We report on new magnetic bimetallic
Fe–Ag nanoparticles
(NPs) which exhibit significant antibacterial and antifungal activities
against a variety of microorganisms including disease causing pathogens,
as well as prolonged action and high efficiency of phosphorus removal.
The preparation of these multifunctional hybrids, based on direct
reduction of silver ions by commercially available zerovalent iron
nanoparticles (nZVI) is fast, simple, feasible in a large scale with
a controllable silver NP content and size. The microscopic observations
(transmission electron microscopy, scanning electron microscopy/electron
diffraction spectroscopy) and phase analyses (X-ray diffraction, Mössbauer
spectroscopy) reveal the formation of Fe<sub>3</sub>O<sub>4</sub>/γ-FeOOH
double shell on a “redox” active nZVI surface. This
shell is probably responsible for high stability of magnetic bimetallic
Fe–Ag NPs during storage in air. Silver NPs, ranging between
10 and 30 nm depending on the initial concentration of AgNO<sub>3</sub>, are firmly bound to Fe NPs, which prevents their release even during
a long-term sonication. Taking into account the possibility of easy
magnetic separation of the novel bimetallic Fe–Ag NPs, they
represent a highly promising material for advanced antimicrobial and
reductive water treatment technologies
Detection of Prosthetic Joint Infection Based on Magnetically Assisted Surface Enhanced Raman Spectroscopy
Accurate
and rapid diagnosis of prosthetic joint infection (PJI)
is vital for rational and effective therapeutic management of this
condition. Several diagnostic strategies have been developed for discriminating
between infected and noninfected cases. However, none of them can
reliably diagnose the whole spectrum of clinical presentations of
PJI. Here, we report a new method for PJI detection based on magnetically
assisted surface enhanced Raman spectroscopy (MA-SERS) using streptavidin-modified
magnetic nanoparticles (MNP@Strep) whose surface is functionalized
with suitable biotinylated antibodies and then coated with silver
nanoparticles by self-assembly. The high efficiency of this approach
is demonstrated by the diagnosis of infections caused by two bacterial
species commonly associated with PJI, namely, <i>Staphylococcus
aureus</i> and <i>Streptococcus pyogenes</i>. The method’s
performance was verified with model samples of bacterial lysates and
with four real-matrix samples of knee joint fluid spiked with live
pathogenic bacterial cells. This procedure is operationally simple,
versatile, inexpensive, and quick to perform, making it a potentially
attractive alternative to established diagnostic techniques based
on Koch’s culturing or colony counting methods
Synthesis, Cytostatic, Antimicrobial, and Anti-HCV Activity of 6‑Substituted 7‑(Het)aryl-7-deazapurine Ribonucleosides
A series of 80 7-(het)aryl-
and 7-ethynyl-7-deazapurine ribonucleosides
bearing a methoxy, methylsulfanyl, methylamino, dimethylamino, methyl,
or oxo group at position 6, or 2,6-disubstituted derivatives bearing
a methyl or amino group at position 2, were prepared, and the biological
activity of the compounds was studied and compared with that of the
parent 7-(het)aryl-7-deazaadenosine series. Several of the compounds,
in particular 6-substituted 7-deazapurine derivatives bearing a furyl
or ethynyl group at position 7, were significantly cytotoxic at low
nanomolar concentrations whereas most were much less potent or inactive.
Promising activity was observed with some compounds against <i>Mycobacterium bovi</i>s and also against hepatitis C virus in
a replicon assay
Lipophosphonoxins II: Design, Synthesis, and Properties of Novel Broad Spectrum Antibacterial Agents
The
increase in the number of bacterial strains resistant to known
antibiotics is alarming. In this study we report the synthesis of
novel compounds termed Lipophosphonoxins II (LPPO II). We show that
LPPO II display excellent activities against Gram-positive and -negative
bacteria, including pathogens and multiresistant strains. We describe
their mechanism of action–plasmatic membrane pore-forming activity
selective for bacteria. Importantly, LPPO II neither damage nor cross
the eukaryotic plasmatic membrane at their bactericidal concentrations.
Further, we demonstrate LPPO II have low propensity for resistance
development, likely due to their rapid membrane-targeting mode of
action. Finally, we reveal that LPPO II are not toxic to either eukaryotic
cells or model animals when administered orally or topically. Collectively,
these results suggest that LPPO II are highly promising compounds
for development into pharmaceuticals