A new approach to direct quantitative detection of small molecules (haptens) by dynamic light scattering biosensing is presented. The proposed technique implements a homogeneous competitive ...immunoassay and is based on optical detection of specific inhibition of nanoparticle aggregation induced by the analyte in a sample. The technique performance was tested both in buffer and milk for detection of chloramphenicol – antibiotic relevant to food safety diagnostics. Good specificity, sensitivity (LOD in milk is 2.4 ng/ml), precision (4.0 ± 1.2%), ruggedness (8.3%), and 96% recovery in conjunction with a record wide dynamic range (3 orders of magnitude) of the nanosensing technique were demonstrated. Such characteristics complemented by the assay simplicity (no washing step) and a short assay time make the approach attractive for application as an analytical platform for point-of-care and field-oriented diagnostics.
Graphical abstract
Polar metals, commonly defined by the coexistence of polar crystal structure and metallicity, are thought to be scarce because the long-range electrostatic fields favoring the polar structure are ...expected to be fully screened by the conduction electrons of a metal. Moreover, reducing from three to two dimensions, it remains an open question whether a polar metal can exist. Here we report on the realization of a room temperature two-dimensional polar metal of the B-site type in tri-color (tri-layer) superlattices BaTiO
/SrTiO
/LaTiO
. A combination of atomic resolution scanning transmission electron microscopy with electron energy-loss spectroscopy, optical second harmonic generation, electrical transport, and first-principles calculations have revealed the microscopic mechanisms of periodic electric polarization, charge distribution, and orbital symmetry. Our results provide a route to creating all-oxide artificial non-centrosymmetric quasi-two-dimensional metals with exotic quantum states including coexisting ferroelectric, ferromagnetic, and superconducting phases.
Thermochemistry of Iridium Fluorides Nikitin, M. I.; Alikhanyan, A. S.
Russian journal of inorganic chemistry,
11/2022, Letnik:
67, Številka:
11
Journal Article
Recenzirano
The experimental data on the joint fluorination of metallic iridium and platinum with molecular fluorine in the temperature range 654–880 K have been analyzed. The reasons for the decrease in the ...thermodynamic activity of metals and the possibility of the formation of new phases on their surfaces have been quantitatively considered. The Δ
r
H
°(0) of reactions, kJ/mol, have been determined: Ir(c) + PtF
4
(g) = IrF
4
(g) + Pt(c), 23.0 ± 4.5; Ir(c) + 2IrF
6
(g) = 3IrF
4
(g), 217.7 ± 8.6; Ir
2
F
6
(c) + IrF
6
(g) = 3IrF
4
(g), 396.2 ± 21.3. The standard enthalpies of formation of the following iridium fluorides have been recommended: Δ
f
H
°(Ir
2
F
6
, c, 0) = ‒1012.6 ± 15.5 kJ/mol, Δ
f
H
°(IrF
4
, g, 0) = –482.3 ± 7.7 kJ/mol, and Δ
f
H
°(IrF
6
, g, 0) = –832.3 ± 12.7 kJ/mol.
With the rise of drug resistance, bacteriophages and bacteriophage-derived proteins may become an efficient successor to traditional antibiotics. While the enormous natural diversity of the phages ...allows matching virtually any bacteria, identification of the potentially life-saving phage is currently a tedious and time-consuming challenge that often cannot be performed within a reasonable time. Here we show a rapid 1-min bacteriophage screening assay based on specially constructed phage-mimicking nanoagents and surface plasmon resonance effect. Within the assay, a panel of phage-mimicking gold nanoparticles, possessing the specificity and enzymatic activity of a particular phage, is mixed with a suspension of the bacteria of interest. The spectral behaviour of the assay mix allows measurement of two critical parameters of the nanoagents and the corresponding bacteriophages: 1) direct assessment of their specificity due to convergence of the particles on the cell walls, and more importantly, 2) real-time evaluation of their enzymatic activity for the destruction of the cell capsule via detection of nanoagent detachment from the surface of bacteria. The proposed assay overcomes the current time limitations of the phage-bacteria matching procedures and thereby can facilitate faster development and adoption of phage-based therapies as a much-needed alternative to traditional antibiotics.
Protein structure prediction continues to pose multiple challenges despite outstanding progress that is largely attributable to the use of novel machine learning techniques. One of the widely used ...representations of local 3D structure—protein blocks (PBs)—can be treated in a similar way to secondary structure classes. Here, we present a new approach for predicting local conformation in terms of PB classes solely from amino acid sequences. We apply the RMSD metric to ensure unambiguous future 3D protein structure recovery. The selection of statistically assessed features is a key component of the proposed method. We suggest that ML input features should be created from the statistically significant predictors that are derived from the amino acids’ physicochemical properties and the resolved structures’ statistics. The statistical significance of the suggested features was assessed using a stepwise regression analysis that permitted the evaluation of the contribution and statistical significance of each predictor. We used the set of 380 statistically significant predictors as a learning model for the regression neural network that was trained using the PISCES30 dataset. When using the same dataset and metrics for benchmarking, our method outperformed all other methods reported in the literature for the CB513 nonredundant dataset (for the PBs, Q16 = 81.01%, and for the DSSP, Q3 = 85.99% and Q8 = 79.35%).
Aim
Create a method for highly sensitive, selective, rapid and easy‐to‐use detection and identification of economically significant potato pathogens, including viruses, bacteria and oomycetes, be it ...single pathogen, or a range of various pathogens occurring simultaneously.
Methods and Results
Test‐systems for real‐time PCR, operating in the unified amplification regime, have been developed for Phytophthora infestans, Pectobacterium atrosepticum, Dickeya dianthicola, Dickeya solani, Ralstonia solanacearum, Pectobacterium carotovorum, Clavibacter michiganensis subsp. sepedonicus, potato viruses Y (ordinary and necrotic forms as well as indiscriminative test system, detecting all forms), A, X, S, M, potato leaf roll virus, potato mop top virus and potato spindle tuber viroid. The test‐systems (including polymerase and revertase) were immobilized and lyophilized in miniature microreactors (1·2 μl) on silicon DNA/RNA microarrays (micromatrices) to be used with a mobile AriaDNA® amplifier.
Conclusions
Preloaded 30‐reaction micromatrices having shelf life of 3 and 6 months (for RNA‐ and DNA‐based pathogens, respectively) at room temperature with no special conditions were successfully tested on both reference and field samples in comparison with traditional ELISA and microbiological methods, showing perfect performance and sensitivity (1 pg).
Significance and Impact of the Study
The accurate, rapid and user‐friendly diagnostic system in a micromatrix format may significantly contribute to pathogen screening and phytopathological studies.
Developing combined cancer therapy strategies is of utmost importance as it can enhance treatment efficacy, overcome drug resistance, and ultimately improve patient outcomes by targeting multiple ...pathways and mechanisms involved in cancer growth and progression. Specifically, the potential of developing a combination chemo&photothermal therapy using targeted polymer nanoparticles as nanocarriers offers a promising approach for synergistic cancer treatment by combining the benefits of both therapies, such as targeted drug delivery and localized hyperthermia. Here, we report the first targeted anti-HER2 PLGA nanocarriers, called targosomes, that simultaneously possess photothermal, chemotherapeutic and diagnostic properties using only molecular payloads. Biocompatible poly(lactic-co-glycolic acid), PLGA, nanoparticles were loaded with photosensitizer phthalocyanine, diagnostic dye Nile Blue, and chemotherapeutic drug irinotecan, which was chosen as a result of screening a panel of theragnostic nanoparticles. The targeted delivery to cell surface oncomarker HER2 was ensured by nanoparticle modification with the anti-HER2 monoclonal antibody, trastuzumab, using the one-pot synthesis method without chemical conjugation. The irradiation tests revealed prominent photothermal properties of nanoparticles, namely heating by 35 °C in 10 min. Nanoparticles exhibited a 7-fold increase in binding and nearly an 18-fold increase in cytotoxicity for HER2-overexpressing cells compared to cells lacking HER2 expression. This enhancement of cytotoxicity was further amplified by >20-fold under NIR light irradiation. In vivo studies proved the efficacy of nanoparticles for bioimaging of primary tumor and metastasis sites and demonstrated 93% tumor growth inhibition, making these nanoparticles excellent candidates for translation into theragnostic applications.
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