Chemical Synthesis of Iron Antimonide (FeSb₂) and Its Thermoelectric Properties

Low temperature thermoelectric (TE) materials are in demand for more efficient cooling and power generation applications. Iron antimonide (FeSb₂) draws great attention over the past few years because of its enhanced power factor values. Polycrystalline bulk FeSb₂ nanopowder was prepared via a low-temperature molten salts approach followed by subsequent thermal treatment in synthetic air and hydrogen gas for calcination and reduction reactions, respectively. Structural analysis confirms the desired final phase with submicrometer grain size and high compaction density after consolidation using spark plasma sintering (SPS). TE transport properties revealed that the material is n-type below 150 K and p-type above this temperature; this suggests antimony vacancies in FeSb₂. The electrical conductivity increased significantly, and the highest conductivity achieved was 6000 S/cm at 100 K. The maximum figure-of-merit, ZT, of 0.04 is achieved at 500 K, which is about 6 times higher than the earlier reported state-of-the art ZT value for the same material

Proteomics Analysis Reveals Distinct Corona Composition on Magnetic Nanoparticles with Different Surface Coatings: Implications for Interactions with Primary Human Macrophages

<div><p>Superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as promising contrast agents for magnetic resonance imaging. The influence of different surface coatings on the biocompatibility of SPIONs has been addressed, but the potential impact of the so-called corona of adsorbed proteins on the surface of SPIONs on their biological behavior is less well studied. Here, we determined the composition of the plasma protein corona on silica-coated <i>versus</i> dextran-coated SPIONs using mass spectrometry-based proteomics approaches. Notably, gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed distinct protein corona compositions for the two different SPIONs. Relaxivity of silica-coated SPIONs was modulated by the presence of a protein corona. Moreover, the viability of primary human monocyte-derived macrophages was influenced by the protein corona on silica-coated, but not dextran-coated SPIONs, and the protein corona promoted cellular uptake of silica-coated SPIONs, but did not affect internalization of dextran-coated SPIONs.</p></div

Plasma protein corona composition on CSNP.

<p>Classification of identified corona proteins according to differentially enriched Gene Ontology (GO) categories and KEGG pathways. The relative abundances of the proteins, as a percentage of total estimated protein abundance in the sample, are shown and each replicate is plotted separately. A significant enrichment of plasma proteins absorbed on the CSNP surface involved (A) KEGG Complement and coagulation cascades pathway, (B) GO Regulation of coagulation, (C) GO Negative regulation of coagulation, (D) GO Positive regulation of coagulation, (E) GO Regulation of fibrinolysis, (F) GO Fibrinogen complex, (G) GO Heparin binding, (H) GO Regulation of defense response, and (I) GO Lipid biosynthetic process. For further details, refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129008#pone.0129008.s009" target="_blank">S3</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129008#pone.0129008.s011" target="_blank">S5</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129008#pone.0129008.s012" target="_blank">S6</a> Tables.</p

Most abundant CSNP nanoparticle enriched proteins

<p>Uniprot = Uniprot accession, AAs = Number of Amino acids in the protein, MW.kDa. = molecular weight of the protein (calculated), calc.pI = protein isoelectric point (calculated), Symbol = Official gene symbol, GeneName = Official gene name, log2FC = log2 transformed fold‐change relative to plasma, CSNP% = relative abundance of the protein in the CSNP corona, Nmag% = NMag abundance, Plasma% = plasma abundance, FDR q‐value = false discovery rate corrected p‐value for the difference relative to plasma, CSNP = core shell nano particles; Nmag = nanomag‐D‐spio. Plasma = crude plasma (control).</p><p>Most abundant CSNP nanoparticle enriched proteins</p

Relaxivity properties of SPIONs with/without plasma corona

<p>Relaxivity values are measured at 20 MHz (0.47 T) and 60 MHz (1.41 T) in PBS (37°C).</p><p>^aResults presented as mean values ± SD, n = 3.</p><p>^bCSNP@protein corona particles are unstable over the measurements time at 60 MHz.</p><p>Relaxivity properties of SPIONs with/without plasma corona</p

Distinct plasma protein corona composition on SPIONs with different surface coating.

<p>Cluster analysis of SPION-bound plasma proteins <i>versus</i> plasma proteins. Red color denotes counts higher than average when compared to other samples. Blue denotes counts lower than average (refer to legend top right corner). Clusters are numbered 1–5 (cf. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129008#pone.0129008.s010" target="_blank">S4 Table</a>). Clusters 2 and 5 contain proteins that are enriched in the CSNP corona. Cluster 1 proteins are enriched in the nanomag-D-spio corona and clusters 3–4 contain plasma-enriched proteins. For gene ontology (GO) enrichment analysis of the corona-specific clusters, refer to Figs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129008#pone.0129008.g005" target="_blank">5</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129008#pone.0129008.s005" target="_blank">S5</a>.</p

Biocompatibility assessment of SPIONs with or without a ‘hard’ corona of plasma proteins.

<p>Human monocyte-derived macrophages were exposed for 2 h (A, D), 6 h (B, E) or 24 h (C, F) to the indicated doses (μL/mL) of CSNP or CSNP + protein corona (A-C), or to nanomag-D-spio or nanomag-D-spio + protein corona (D-F). Macrophage viability was determined using the MTT assay. Cells were cultured in the absence of FBS to exclude any confounding effects of serum proteins. Results are presented as % mitochondrial function (mean values ± S.D.) from four independent experiments using cells isolated from healthy human donors. Statistical analysis was performed using Tukey post-hoc test following one way ANOVA (**p<0.01, ***p<0.001).</p

Most abundant nanomag-D-spio enriched proteins

<p>Uniprot = Uniprot accession, AAs = Number of Amino acids in the protein, MW.kDa. = molecular weight of the protein (calculated), calc.pI = protein isoelectric point (calculated), Symbol = Official gene symbol, GeneName = Official gene name, log2FC = log2 transformed fold‐change relative to plasma, CSNP% = relative abundance of the protein in the CSNP corona, Nmag% = NMag abundance, Plasma% = plasma abundance, FDR q‐value = false discovery rate corrected p‐value for the difference relative to plasma, CSNP = core shell nano particles; Nmag = nanomag‐D‐spio. Plasma = crude plasma (control).</p><p>Most abundant nanomag-D-spio enriched proteins</p