@misc{10481/61950,
year = {2019},
month = {6},
url = {http://hdl.handle.net/10481/61950},
abstract = {Numerous studies have focused on the bacterial synthesis of palladium nanoparticles
(bio-Pd NPs), via uptake of Pd (II) ions and their enzymatically-mediated reduction to Pd (0).
Cells of Desulfovibrio desulfuricans (obligate anaerobe) and Escherichia coli (facultative anaerobe,
grown anaerobically) were exposed to low-dose radiofrequency (RF) radiation(microwave (MW)
energy) and the biosynthesized Pd NPs were compared. Resting cells were exposed to microwave
energy before Pd (II)-challenge. MW-injured Pd (II)-treated cells (and non MW-treated controls)
were contacted with H2 to promote Pd(II) reduction. By using scanning transmission electron
microscopy (STEM) associated with a high-angle annular dark field (HAADF) detector and energy
dispersive X-ray (EDX) spectrometry, the respective Pd NPs were compared with respect to their mean
sizes, size distribution, location, composition, and structure. Differences were observed following
MWinjury prior to Pd(II) exposure versus uninjured controls. With D. desulfuricans the bio-Pd NPs
formed post-injury showed two NP populations with different sizes and morphologies. The first,
mainly periplasmically-located, showed polycrystalline Pd nano-branches with different crystal
orientations and sizes ranging between 20 and 30 nm. The second NPpopulation, mainly located
intracellularly, comprised single crystals with sizes between 1 and 5 nm. Bio-Pd NPs were produced
mainly intracellularly by injured cells of E. coli and comprised single crystals with a size distribution
between 1 and 3 nm. The polydispersity index was reduced in the bio-Pd made by injured cells of
E. coli and D. desulfuricans to 32% and 39%, respectively, of the values of uninjured controls, indicating
an increase in NP homogeneity of 30–40% as a result of the prior MWinjury. The observations are
discussed with respect to the different locations of Pd(II)-reducing hydrogenases in the two organisms
and with respect to potential implications for the catalytic activity of the produced NPs following
injury-associated altered NP patterning.},
organization = {The study was supported by NERC (grant NE/L014076/1) to LEM.},
publisher = {MDPI},
keywords = {Palladium nanoparticles},
keywords = {Microwave injured cells},
keywords = {Microwave energy},
keywords = {Escherichia coli},
keywords = {Desulfovibrio desulfuricans},
title = {Characterization of Palladium Nanoparticles Produced by Healthy and Microwave-Injured Cells of Desulfovibrio desulfuricans and Escherichia coli},
doi = {10.3390/nano9060857},
author = {Gómez Bolívar, Jaime and Mikheenko, Iryna P. and Macaskie, Lynne and Merroun, Mohamed Larbi},
}