A Novel Strategy for Selective Thyroid Hormone Determination Based on an Electrochemical Biosensor with Graphene Nanocomposite

This article presents a novel and selective electrochemical bioassay with antibody and laccase for the determination of free thyroid hormone (free triiodothyronine, fT3). The biosensor was based on a glassy carbon electrode modified with a Fe₃O₄@graphene nanocomposite with semiconducting properties, an antibody (anti-PDIA3) with high affinity for fT3, and laccase, which was responsible for catalyzing the redox reaction of fT3. The electrode modification procedure was investigated using a cyclic voltammetry technique, based on the response of the peak current after modifications. All characteristic working parameters of the developed biosensor were analyzed using differential pulse voltammetry. Obtained experimental results showed that the biosensor revealed a sensitive response to fT3 in a concentration range of 10-200 µM, a detection limit equal to 27 nM, and a limit of quantification equal to 45.9 nM. Additionally, the constructed biosensor was selective towards fT3, even in the presence of interference substances: ascorbic acid, tyrosine, and levothyroxine, and was applied for the analysis of fT3 in synthetic serum samples with excellent recovery results. The designed biosensor also exhibited good stability and can find application in future medical diagnostics.

Hafnium (IV) oxide obtained by atomic layer deposition (ALD) technology promotes early osteogenesis via activation of Runx2-OPN-mir21A axis while inhibits osteoclasts activity

BACKGROUND

Due to increasing aging of population prevalence of age-related disorders including osteoporosis is rapidly growing. Due to health and economic impact of the disease, there is an urgent need to develop techniques supporting bone metabolism and bone regeneration after fracture. Due to imbalance between bone forming and bone resorbing cells, the healing process of osteoporotic bone is problematic and prolonged. Thus searching for agents able to restore the homeostasis between these cells is strongly desirable.

RESULTS

In the present study, using ALD technology, we obtained homogeneous, amorphous layer of hafnium (IV) oxide (HfO2). Considering the specific growth rate (1.9Å/cycle) for the selected process at the temperature of 90 °C, we performed the 100 nm deposition process, which was confirmed by measuring film thickness using reflectometry. Then biological properties of the layer were investigated with pre-osteoblast (MC3T3), pre-osteoclasts (4B12) and macrophages (RAW 264.7) using immunofluorescence and RT-qPCR. We have shown, that HfO2 (i) enhance osteogenesis, (ii) reduce osteoclastogenesis (iii) do not elicit immune response and (iv) exert anti-inflammatory effects.

CONCLUSION

HfO2 layer can be applied to cover the surface of metallic biomaterials in order to enhance the healing process of osteoporotic bone fracture.

Age-dependent impairment of adipose-derived stem cells isolated from horses

BACKGROUND

Progressive loss of cell functionality caused by an age-related impairment in cell metabolism concerns not only mature specialized cells but also its progenitors, which significantly reduces their regenerative potential. Adipose-derived stem cells (ASCs) are most commonly used in veterinary medicine as an alternative treatment option in ligaments and cartilage injuries, especially in case of high-value sport horses. Therefore, the main aim of this study was to identify the molecular alternations in ASCs derived from three age-matched horse groups: young (< 5), middle-aged (5-15), and old (> 15 years old).

METHODS

ASCs were isolated from three age-matched horse groups using an enzymatic method. Molecular changes were assessed using qRT-PCR, ELISA and western blot methods, flow cytometry-based system, and confocal and scanning electron microscopy.

RESULTS

Our findings showed that ASCs derived from the middle-aged and old groups exhibited a typical senescence phenotype, such as increased percentage of G1/G0-arrested cells, binucleation, enhanced β-galactosidase activity, and accumulation of γH2AX foci, as well as a reduction in cell proliferation. Moreover, aged ASCs were characterized by increased gene expression of pro-inflammatory cytokines and miRNAs (interleukin 8 (IL-8), IL-1β, tumor necrosis factor α (TNF-α), miR-203b-5p, and miR-16-5p), as well as apoptosis markers (p21, p53, caspase-3, caspase-9). In addition, our study revealed that the protein level of mitofusin 1 (MFN1) markedly decreased with increasing age. Aged ASCs also displayed a reduction in mRNA levels of genes involved in stem cell homeostasis and homing, like TET-3, TET-3 (TET family), and C-X-C chemokine receptor type 4 (CXCR4), as well as protein expression of DNA methyltransferase (DNMT1) and octamer transcription factor 3/4 (Oct 3/4). Furthermore, we observed a higher splicing ratio of XBP1 (X-box binding protein 1) mRNA, indicating elevated inositol-requiring enzyme 1 (IRE-1) activity and, consequently, increased endoplasmic reticulum (ER) stress. We also observed reduced levels of glucose transporter 4 (GLUT-4) and insulin receptor (INSR) which indicated impaired insulin sensitivity.

CONCLUSIONS

Obtained data suggest that ASCs derived from horses older than 5 years old exhibited several molecular alternations which markedly limit their regenerative capacity. The results provide valuable information that allows for a better understanding of the molecular events occurring in ASCs in the course of aging and may help to identify new potential drug targets to restore their regenerative potential.

Promotion through external magnetic field of osteogenic differentiation potential in adipose-derived mesenchymal stem cells: Design of polyurethane/poly(lactic) acid sponges doped with iron oxide nanoparticles

Recently, iron oxide nanoparticles (IONPs) have gathered special attention in regenerative medicine. Owing to their magnetic and bioactive properties, IONPs are utilized in the fabrication of novel biomaterials. Yet, there was no report regarding thermoplastic polyurethane (TPU) and poly(lactic acid) (PLA) polymer doped with IONPs on osteogenic differentiation of mesenchymal stem cells. Thus the objectives of presented study was to: (a) fabricate magnetic TPU + PLA sponges doped with iron (III) oxide Fe₂ O₃ nanoparticles; (b) investigate the effects of biomaterial and its exposition to static magnetic field (MF) on osteogenic differentiation, proliferation, and apoptosis in adipose-derived mesenchymal stem cells (ASCs). TPU + PLA sponges were prepared using solvent casting technique while incorporation of the Fe₂ O₃ nanoparticles was performed with solution cast method. RT-PCR was applied to evaluate expression of osteogenic-related genes and integrin's in cells cultured on fabricated materials with or without the stimulation of static MF. MF stimulation enhanced the expression of osteopontin and collagen type I while decreased expression of bone morphogenetic protein 2 in tested magnetic materials-TPU + PLA/1% Fe₂ O₃ and TPU + PLA/5% Fe₂ O₃ . Therefore, TPU + PLA sponges doped with IONPs and exposure to MF resulted in improved osteogenic differentiation of ASC.

Adipose-Derived Mesenchymal Stem Cells Isolated from Patients with Type 2 Diabetes Show Reduced "Stemness" through an Altered Secretome Profile, Impaired Anti-Oxidative Protection, and Mitochondrial Dynamics Deterioration

The widespread epidemic of obesity and type 2 diabetes (T2D), suggests that both disorders are closely linked. Several pre-clinical and clinical studies have showed that adipose-derived mesenchymal stem cells (ASC) transplantation is efficient and safe. Moreover, scientists have already highlighted the therapeutic capacity of their secretomes. In this study, we used quantitative PCR, a flow cytometry-based system, the ELISA method, spectrophotometry, and confocal and scanning electron microscopy, to compare the differences in proliferation activity, viability, morphology, mitochondrial dynamics, mRNA and miRNA expression, as well as the secretory activity of ASCs derived from two donor groups-non-diabetic and T2D patients. We demonstrated that ASCs from T2D patients showed a reduced viability and a proliferative potential. Moreover, they exhibited mitochondrial dysfunction and senescence phenotype, due to excessive oxidative stress. Significant differences were observed in the expressions of miRNA involved in cell proliferations (miR-16-5p, miR-146a-5p, and miR-145-5p), as well as miRNA and genes responsible for glucose homeostasis and insulin sensitivity (miR-24-3p, 140-3p, miR-17-5p, SIRT1, HIF-1α, LIN28, FOXO1, and TGFβ). We have observed a similar correlation of miR-16-5p, miR-146a-5p, miR-24-3p, 140-3p, miR-17-5p, and miR-145-5p expression in extracellular vesicles fraction. Furthermore, we have shown that ASCT2D exhibited a lower VEGF, adiponectin, and CXCL-12 secretion, but showed an overproduction of leptin. We have shown that type 2 diabetes attenuated crucial functions of ASC, like proliferation, viability, and secretory activity, which highly reduced their therapeutic efficiency.

Identification of a potent inhibitor of type II secretion system from Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen infecting human population. The pathogen is becoming a serious health problem due to its ability to evade normal immune response of the host and multiple drug resistance to many antibiotics. The pathogen has 2 major virulence systems of which the type III secretion system (T3SS) is of major concern to humans. A third system, type 2 secretion system (T2SS), is common to bacteria and used to secrete exotoxin A (ExoA) responsible for human cell destruction. To help bypass the drug resistance, a strategy to block the T2SS based on a low similarity between human ATPases and the essential ATPases of the T3SS and T2SS of P. aeruginosa, was used. An in silico-optimized inhibitor of T3SS, made directly from the computer-optimized of previously published compounds and their combinatorial libraries, showed IC₅₀ = 1.3 ± 0.2 μM in the T2SS ExoA secretion blocking test. The compound was non-toxic to human lung epithelial cell line A549 and could block cellular destruction of those cells in a cell infection model at 200 μM for at least 24 h. The compound could be a lead candidate for the development of T2SS virulence blockers of Pseudomonas aeruginosa.

Experimental Verification of the Theory on Rotational Motions of Prolate Luminescent Molecules in Solution

Theories I [1] and II [2] on rotational motions of prolate molecules in solvents of different viscosities were verified for a series of luminescent compounds, the transition moments of which lie along their longer axes. Better agreement between the experimental and theoretical results was found with theory I. Effective volumes and moments of inertia were determined for the molecules studied.

Viskositäts-und Lösungsmittelabhängigkeit der Fluoreszenzanisotropie und der Lebensdauer von p-Terphenyl

The fluorescence anisotropics (FA) r and the lifetimes of p-terphenyl in different solvents have been measured, the effective volumes and the rotational relaxation times being determined. The deviation from the linear dependence of 1/r on 1/η (η-viscosity of the solvent) may explained by the length of the p-terphenyl molecule. The FA measurements were carried out by a method with an Arago compensator, a new method of the automatization of measurements being employed.

Notizen: Anisotropic Fluorescence of Donor-Acceptor-Substituted trans-Stilbenes in Solvents of Different Polarities and Low Viscosity

The fluorescence anisotropy (FA) and mean lifetime τF of substituted trans-stilbenes was investigated at 293 K in the nonpolar and polar low viscosity solvents n-heptane, toluene, acetonitrile, dimethylformamide and n-propanol. In most cases, the fluorescence was found to be strongly anisotropic due to a very short lifetime of the donor- acceptor-substituted trans-stilbenes.

Relaxation Time Studies of Excited Oxido-Substituted p-Oligophenylenes in Different Solvents

Effective volumes, moments of inertia and Debye relaxation times in the excited state were determined for some oxido-substituted p-oligophenylenes by the method of fluorescence depolarization in nonpolar and polar solvents of different viscosities.