Achieving an improved understanding of catalyst properties, with ability to predict new catalytic materials, is key to overcoming the inherent limitations of metal oxide based gas sensors associated ...with rather low sensitivity and selectivity, particularly under highly humid conditions. This study introduces newly designed bimetallic nanoparticles (NPs) employing bimetallic Pt‐based NPs (PtM, where M = Pd, Rh, and Ni) via a protein encapsulating route supported on mesoporous WO3 nanofibers. These structures demonstrate unprecedented sensing performance for detecting target biomarkers (even at p.p.b. levels) in highly humid exhaled breath. Sensor arrays are further employed to enable pattern recognition capable of discriminating between simulated biomarkers and controlled breath. The results provide a new class of multicomponent catalytic materials, demonstrating potential for achieving reliable breath analysis sensing.
Effective strategy to readily synthesize highly dispersed Pt‐based bimetallic (PtM, where M = Pd, Rh, and Ni) NPs as a new class of active catalysts is successfully developed on the highly porous architecture of 1D WO3 nanofibers via a protein template, i.e., apoferritin, in combination with the electrospinning method for superior exhaled‐breath sensors.
Metal oxide nanosheets having high mesoporosity, grain size distribution of 5–10 nm, and ultrathin thickness have attracted much attention due to their intriguing properties such as high ...surface‐to‐volume ratio and superior chemical activities. However, 2D nanostructures tend to restack, inducing a decrease in accessible surface area and a number of pores. To solve this problem, herein, a unique synthetic method of crumpled metal oxide nanosheets using spray pyrolysis of metal ion–coated graphene oxide, followed by heat treatment, is reported. This method is applicable not only to single‐component metal oxides but also to heterogeneous multicomponent metal oxides in which composition can be controlled. Crumpled SnO2, ZnO, and Co3O4 as well as SnO2/ZnO and SnO2/Co3O4 nanosheets with heterogeneous interfaces are successfully synthesized and used as superior gas sensing layers. Because of the abundant reaction sites, well‐developed porosity for high gas accessibility, the formation of heterojunctions, the crumpled SnO2/ZnO and SnO2/Co3O4 nanosheets exhibit outstanding sensing performance (Rair/Rgas = 20.25 toward 5 ppm formaldehyde, and Rair/Rgas = 14.13 toward 5 ppm acetone, respectively). This study can contribute to the realization of a family of heterogeneous crumpled metal oxide nanosheets that can be applied to various research fields.
A general synthetic platform of hierarchically structured holey metal oxide nanosheets is achieved via a graphene oxide templating route and spray pyrolysis technique. The crumpled heterogeneous 2D metal oxide (crumpled H_2D MO) as a sensing layer exhibits improved sensing performance of formaldehyde (crumpled 2D SnO2/ZnO) and acetone (crumpled 2D SnO2/Co3O4) molecules due to the high porosity, surface area, and heterojunction effect.
Immunotherapy has emerged as a promising anti-cancer treatment, however, little is known about the genetic characteristics that dictate response to immunotherapy. We develop a transcriptional ...predictor of immunotherapy response and assess its prediction in genomic data from ~10,000 human tissues across 30 different cancer types to estimate the potential response to immunotherapy. The integrative analysis reveals two distinct tumor types: the mutator type is positively associated with potential response to immunotherapy, whereas the chromosome-instable type is negatively associated with it. We identify somatic mutations and copy number alterations significantly associated with potential response to immunotherapy, in particular treatment with anti-CTLA-4 antibody. Our findings suggest that tumors may evolve through two different paths that would lead to marked differences in immunotherapy response as well as different strategies for evading immune surveillance. Our analysis provides resources to facilitate the discovery of predictive biomarkers for immunotherapy that could be tested in clinical trials.
Conductive metal–organic frameworks (cMOFs) are emerging materials for various applications due to their high surface area, high porosity, and electrical conductivity. However, it is still ...challenging to develop cMOFs having high surface reactivity and durability. Here, highly active and stable cMOF are presented via the confinement of bimetallic nanoparticles (BNPs) in the pores of a 2D cMOF, where the confinement is guided by dipolar‐interaction‐induced site‐specific nucleation. Heterogeneous metal precursors are bound to the pores of 2D cMOFs by dipolar interactions, and the subsequent reduction produces ultrasmall (≈1.54 nm) and well‐dispersed PtRu NPs confined in the pores of the cMOF. PtRu‐NP‐decorated cMOFs exhibit significantly enhanced chemiresistive NO2 sensing performances, owing to the bimetallic synergies of PtRu NPs and the high surface area and porosity of cMOF. The approach paves the way for the synthesis of highly active and conductive porous materials via bimetallic and/or multimetallic NP loading.
Ultrasmall bimetallic nanoparticles (BNPs) are confined in pores of 2D conductive metal–organic frameworks (cMOFs). BNPs in cMOFs significantly improve the NO2‐sensing performance, owing to the bimetallic synergies of PtRu NPs and the high surface area and porosity of the cMOF.
As a futuristic diagnosis platform, breath analysis is gaining much attention because it is a noninvasive, simple, and low cost diagnostic method. Very promising clinical applications have been ...demonstrated for diagnostic purposes by correlation analysis between exhaled breath components and specific diseases. In addition, diverse breath molecules, which serve as biomarkers for specific diseases, are precisely identified by statistical pattern recognition studies. To further improve the accuracy of breath analysis as a diagnostic tool, breath sampling, biomarker sensing, and data analysis should be optimized. In particular, development of high performance breath sensors, which can detect biomarkers at the ppb-level in exhaled breath, is one of the most critical challenges. Due to the presence of numerous interfering gas species in exhaled breath, selective detection of specific biomarkers is also important. This Account focuses on chemiresistive type breath sensors with exceptionally high sensitivity and selectivity that were developed by combining hollow protein templated nanocatalysts with electrospun metal oxide nanostructures. Nanostructures with high surface areas are advantageous in achieving high sensitivity because the sensing signal is dominated by the surface reaction between the sensing layers and the target biomarkers. Furthermore, macroscale pores between one-dimensional (1D) nanostructures can facilitate fast gas diffusion into the sensing layers. To further enhance the selectivity, catalytic functionalization of the 1D metal oxide nanostructure is essential. However, the majority of conventional techniques for catalytic functionalization have failed to achieve a high degree of dispersion of nanoscale catalysts due to aggregation on the surface of the metal oxide, which severely deteriorates the sensing properties by lowering catalytic activity. This issue has led to extensive studies on monolithically dispersed nanoscale particles on metal oxides to maximize the catalytic performances. As a pioneering technique, a bioinspired templating route using apoferritin, that is, a hollow protein cage, has been proposed to obtain nanoscale (∼2 nm) catalyst particles with high dispersity. Nanocatalysts encapsulated by a protein shell were first used in chemiresistive type breath sensors for catalyst functionalization on 1D metal oxide structures. We discuss the robustness and versatility of the apoferrtin templating route for creating highly dispersive catalytic NPs including single components (Au, Pt, Pd, Rh, Ag, Ru, Cu, and La) and bimetallic catalysts (PtY and PtCo), as well as the core–shell structure of Au–Pd (Au-core@Pd-shell). The use of these catalysts is essential to establish high performance sensors arrays for the pattern recognition of biomarkers. In addition, novel multicomponent catalysts provide unprecedented sensitivity and selectivity. With this in mind, we discuss diverse synthetic routes for nanocatalysts using apoferritin and the formation of various catalyst–1D metal oxide composite nanostructures. Furthermore, we discuss detection capability of a simulated biomarker gas using the breath sensor arrays and principal component analysis. Finally, future prospects with the portable breath analysis platform are presented by demonstrating the potential feasibility of real-time and on-site breath analysis using chemiresistive sensors.
Cyclic peptides are one of the important chemical groups in the HDAC inhibitor family. Following the success of romidepsin in the clinic, naturally occurring cyclic peptides with a hydrophilic moiety ...have been intensively studied to test their function as HDAC inhibitors. Azumamides A-E, isolated from
, are one of the powerful HDAC inhibitor classes. Structurally, azumamides A-E consist of three
-α-amino acids and unnatural β-amino acids such as 3-amino-2-methyl-5-nonenedioic acid-9-amide (Amnna) and 3-amino-2-methyl-5-nonenoic-1,9-diacid (Amnda). Moreover, azumamides have a retro-arrangement peptide backbone, unlike other naturally occurring cyclopeptide HDAC inhibitors, owing to the
-configuration of all residues. This review summarizes the currently available synthetic methods of azumamides A-E focusing on the synthesis of β-amino acids and macrocyclization. In addition, we overview the structure-activity relationship of azumamides A-E based on reported analogs. Collectively, this review highlights the potentiality of azumamides A-E as an HDAC inhibitor and provides further developmental insight into naturally occurring cyclic peptides in HDAC inhibition.
We aimed to investigate the association between nonalcoholic fatty liver disease (NAFLD) and cerebral small vessel disease (CSVD) burden, especially according to the NAFLD severity. A total of 1,260 ...participants were included. The CSVD burden was assessed with white matter hyperintensities (WMH), lacunes, and microbleeds (MBs) on brain MRI. An ultrasound diagnosis of fatty liver was made based on standard criteria, and the Fibrosis-4 (FIB-4) index was used to classify participants with NAFLD with having a high-intermediate (FIB-4 ≥1.45) or low (FIB-4 < 1.45) probability of advanced fibrosis. A multivariable logistic regression analysis was used to assess the association between NAFLD and the presence of moderate to severe WMH, lacunes, and MBs. NAFLD had a significant association only with moderate to severe WMH (OR: 1.64, 95% CI: 1.10-2.42), even after controlling for cardiometabolic risk factors. A linear trend test showed a significant association between the severity of NAFLD fibrosis and the presence of moderate to severe WMH (p for trend <0.001). Our findings suggest that NAFLD, especially NAFLD with fibrosis, has a significant association with the presence of moderate to severe WMH in cognitively normal individuals, and NAFLD severity predicted more frequent moderate to severe WMH.
ZIF-8: A comparison of synthesis methods Lee, Yu-Ri; Jang, Min-Seok; Cho, Hye-Young ...
Chemical engineering journal (Lausanne, Switzerland : 1996),
07/2015, Volume:
271
Journal Article
Peer reviewed
•ZIF-8 was prepared by 7 different synthesis methods.•Physicochemical properties of the samples were compared.•ZIF-8 with smaller particle size showed better activity in condensation reaction.•Fe3O4 ...nanoparticles entrapped in ZIF-8 enabled effective separation in liquid.
A zeolitic imidazolate framework, ZIF-8, was prepared via a variety of synthesis routes: solvothermal, microwave-assisted, sonochemical, mechanochemical, dry-gel, and microfluidic methods. Their textural properties and morphology were examined by surface area measurements and scanning electron microscopy, and compared with those of commercial ZIF-8. Although the BET surface areas fell within a range of 1250–1600m2g−1, the particle size of the samples prepared by dry-gel and sonochemical routes were significantly smaller than the others, which led to superior performance in the Knoevenagel condensation reaction. The effective incorporation of magnetic Fe3O4 nanoparticles into the ZIF-8 structure for easy particle separation in the liquid phase was feasible using solvothermal, dry-gel and mechanochemical synthesis methods. Dry-gel and mechanochemical synthesis produced a higher ZIF-8 yield.
In this work, catalytic Rh2O3-functionalized WO3 nanofibers (NFs) were synthesized via an electrospinning route and used as a highly selective acetone-sensing layer for potential diagnosis of ...diabetes. Catalytic rhodium nanoparticles (Rh NPs) with average diameters of 5.0±0.52nm, which were synthesized by the polyol process, were dispersed in water with W precursor and poly(vinylpyrrolidone) (PVP) for electrospinning. As-spun Rh NP-loaded W precursor/PVP composite NFs were calcined at 600°C for 1h in air atmosphere to achieve Rh2O3-decorated WO3 NFs. Microstructure evolution and chemical composition of Rh2O3-decorated WO3 NFs as a function of Rh-loading amounts, i.e., 0.01wt%, 0.05wt%, 0.10wt%, and 0.15wt%, were examined using energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The mean size (30nm) of the WO3 crystallites in Rh2O3-decorated WO3 NFs was much smaller than that (60nm) of the WO3 crystallites in pristine WO3 NFs. The Rh2O3-decorated WO3 NFs showed outstanding acetone (CH3COCH3) sensing response (Rair/Rgas=41.2 to 5ppm), which was 4.6 times higher than the response (Rair/Rgas=9.0 to 5ppm) of pristine WO3 NFs at highly humid atmosphere (95% RH). In addition, superior acetone cross-sensitivity of the Rh2O3-decorated WO3 NFs was observed in other interfering gases such as pentane (n-C5H12), ammonia (NH3), toluene (C6H5CH3), carbon monoxide (CO), and ethanol (C2H5OH) at 5ppm. These results are highly promising for the accurate and selective detection of acetone in exhaled breath for potential diagnosis of diabetes.
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