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Catechols are prone to oxidative polymerization as well as complex formation with metal ions. These two features of catechols have played an important role in the construction of functional films on various surfaces. For example, marine antifouling films and antibacterial films were successfully prepared by oxidative polymerization and metal complexation of catechol-containing molecules, respectively. However, the effect of simultaneous metal complexation and oxidative polymerization on functional film formation has not yet been fully investigated. Herein, as a derivative of 3-(3,4-dihydroxyphenyl)-l-alanine (DOPA), we synthesized an ethylene glycol-derivatized DOPA (OEG-DOPA) and formed OEG-DOPA thin films based on (1) oxidative polymerization and (2) the complexation between catechol groups of OEG-DOPA and iron(III) (FeIII) ions. Either or both approaches were used for the film formation. OEG-DOPA film formation was characterized by ellipsometry, contact angle goniometry, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. Among the conditions used, the formation of a uniform film was only achieved with the dual cross-linking system of FeIII complexation and oxidation-induced covalent bond formation. Compared to the uncoated substrate and other OEG-DOPA films prepared under different conditions, the uniform OEG-DOPA film strongly inhibited bacterial adhesion, showing excellent antibacterial capability. We think that our surface-coating strategy can be applied to medical devices, tools, and implants where bacterial adhesion and biofilm formation should be prevented. This work can also serve as a basis for the construction of functional thin films for other catechol-functionalized materials.

Transcriptional regulator proteins are closely involved in essential survival strategies in bacteria. AcrR is a one-component allosteric repressor of the genes associated with lipid transport and antibiotic resistance. When fatty acid ligands bind to the C-terminal ligand-binding cavity of AcrR, a conformational change in the N-terminal operator-binding region of AcrR is triggered, which releases the repressed DNA and initiates transcription. This paper focuses on the structural transition mechanism of AcrR of Mycobacterium tuberculosis upon DNA and ligand binding. AcrR loses its structural integrity upon ligand-mediated structural alteration and bends toward the promoter DNA in a more compact form, initiating a rotational motion. Our functional characterization of AcrR and description of the ligand- and DNA-recognition mechanism may facilitate the discovery of new therapies for tuberculosis.

Here we describe a tetrapod microneedle injector that produces multifunction encoded particles. The custom-built tetrapod-like needle injector consists of spatially oriented microneedles operated by micropump using programmed on and off sequences. For the purpose of this study to achieve various functions from one particle, each constituent contained in a multifunction encoded particle confirms the cesium adsorption of PB, the drug release behavior of DTPA, and rapid mixing of immiscible liquids due to magnetic actuation. We believe that the multi-functionalized particles may have synergistic multifunctional properties and push the boundaries of advanced biomaterials in biomedical engineering.

Dopamine surface chemistry has been of great interest because of its universal coating property and ability to transform nonadhesive molecules into adhesive molecules. Catechol oxidation and intramolecular cyclization underlie the unique property of dopamine (DA) surface chemistry and provide clues for developing new surface modification reagents such as norepinephrine, 5-pyrogallol-2-aminoethane, and perfluorinated DA derivatives. Based on these inspiring properties, a fast and universal surface chemistry technique using 4-(3-aminopropyl)-benzene-1,2-diol (3-catecholpropanamine, CPA) is reported herein. A single carbon insertion in the aliphatic chain of DA gives rise to the significantly accelerated intermolecular assembly and surface coating of CPA. The effect of CPA conjugation on an anticoagulant polysaccharide coating is also investigated. The use of CPA instead of DA to make polysaccharide coating materials improves the coating rate, while maintaining excellent antiplatelet performance on the coated surface.

We investigated the catalytic efficiency of alginate hydrogels used as a catalyst support. An alginate solution containing palladium and magnetic nanoparticles was dropped continuously through a tapered glass capillary using a syringe pump, and the generated alginate droplets were collected in an aqueous solution containing divalent cations. The prepared PdNPs/MNPs-embedded alginate particles were used as a catalyst, catalyst support, and magnetic stirrer for the reduction of 4-nitrophenol. The catalytic reactions were found to depend on the magnetic stirring of the alginate hydrogels. Furthermore, we examined the recyclability while changing the alginate concentration, divalent cation species, and incubation protocols.

In this work, a Prussian blue (PB)/graphene oxide (GO)/chitosan (CS) organic-inorganic composite was successfully synthesized and utilized as an adsorbent for the selective removal of cesium (Cs+) ions. Taking the advantage of synergistic effect GO, CS and PB nanoparticles, the PB/GO/CS composite exhibited maximum adsorption capacity of 48.35 mg g−1 for Cs+ ions. In the presence of competitive monovalent cations (K+ and Na+), PB/GO/CS showed excellent selectivity (86%) for Cs+ ions and had a 6-fold higher distribution coefficient (Kd) than GO/CS. This enhanced adsorption capacity with high selectivity of PB/GO/CS for Cs+ ions may have been attributed to (i) the presence of carboxylic, hydroxyl and amino functional groups on GO/CS matrix which strongly bind Cs+ ions through electrostatic attraction and chelation, and (ii) the trapping of Cs+ ions by the voids of the FCC-structured PB lattice whose size is equivalent to the hydration radius of Cs+ ions. Due to its low-cost, facile preparation, high adsorption capacity, and superior Cs+ ions selectivity, PB/GO/CS is a promising material for the selective removal of the Cs+ ions from the environment and for protecting ecosystems from the radiation hazards.

Over the past two decades, the radiosynthesis of metallic nanoclusters (MNCs) using γ-irradiation (γ-radiosynthesis) has presented a wealth of opportunities for the application of nanomaterials in areas such as medicine, energy, catalysis, and sensors. Unlike conventional methods, this technique provides fully reduced and highly stable MNCs that are free from by-products or impurities. γ-Radiosynthesis has thus proven to be a clean and green approach for bulk fabrication of MNCs with tunable particle sizes and morphologies. More recently, the in-situ decoration of MNCs on support materials using γ-irradiation has attracted much attention due to the synergistic effect between MNCs and the underlying support. In this review, we discuss the current state of research into the mechanisms underlying the γ-radiosynthesis of supported and unsupported mono- and bi-metallic nanoclusters and summarize the use of MNCs in catalysis, sensing, biomedicine, and energy applications.

In this work, a unique one-pot green synthesis technique that utilizes high energy gamma-irradiation technology was successfully designed to fabricate a stable, highly-porous Prussian blue (PB)/polyvinylpyrrolidone (PVP)/reduced graphene oxide (rGO) aerogel (PB@PVP/rGO) with a 3D-network structure, low density, and high mechanical strength. In this synthesis process, PB nanoparticles were generated in situ and then homogenously distributed and entrapped within the PVP/rGO aerogel. The synthesized aerogel exhibited (i) a three-dimensional microporous architecture consisting of an interconnected network structure with an ultra-low density of 0.0273 g cm−3; (ii) remarkable swelling ability in the presence of water at low pH levels; and (iii) strong mechanical stability, leading to excellent deformability without cracks or the loss of structural integrity, due to the double-network structure of the PB@PVP/rGO aerogel and the crosslinking between the stiff GO sheets and the flexible PVP chains. The hydrophilic PB@PVP/rGO aerogel demonstrated the rapid adsorption of Cs+ ions and MB dye due to capillary action; based on the Langmuir model it demonstrated a maximum adsorption capacity of 143.88 and 44.73 mg g−1 for Cs+ and MB, respectively. The PB@PVP/rGO aerogel also exhibited outstanding oil absorption capacity, which we attribute to its highly interconnected porous structure and the presence of oleophilic rGO. The excellent adsorption properties coupling with the unique structural features of this PB@PVP/rGO aerogel make it a promising adsorbent for oil spills and for the removal of environmental pollutants such as Cs+ and MB in water.

N-doped graphene supported quaternary electrocatalyst (PtRuFeCo/NG) was synthesized and evaluated for potential oxygen reduction (ORR) and methanol oxidation reaction (MOR) in fuel cells. The catalyst exhibited excellent MOR (strong CO tolerance, lower onset potential), ORR (four electron transfer) activities and delivered maximum power densities of 778 and 122 mW cm−2 with direct methanol and proton exchange membrane fuel cells, respectively. The N-doping and synergistic effects of alloying low-cost Fe and Co with Pt and Ru makes PtRuFeCo/NG as excellent bifunctional catalyst that greatly reduces the processing cost of fuel cell which is the major problem facing the fuel cell industry.

Autophagy is a lysosome-dependent intracellular degradation machinery that plays an essential role in the regulation of cellular homeostasis. As many studies have revealed that autophagy is related to cancer, neurodegenerative diseases, metabolic diseases, and so on, and it is considered as a promising drug target. Recent advances in structural determination and computational technologies provide important structural information on essential autophagy-related proteins. Combined with high-throughput screening methods, structure-activity relationship studies have led to the discovery of molecules that modulate autophagy. In this review, we summarize the recent structural studies on autophagy-related proteins and the discovery of modulators, indicating that targeting autophagy can be utilized as an effective strategy for novel drug development.

In this work, we prepared two-dimensional (2D) stack-structured aminopropylIsobutyl polyhedral oligomeric silsesquioxane (POSS-NH

The structure-function relationships of toxin-antitoxin (TA) systems from Mycobacterium tuberculosis have prompted the development of novel and effective antimicrobial agents that selectively target this organism. The artificial activation of toxins by peptide inhibitors can lead to the growth arrest and eventual death of bacterial cells. Optimizing candidate peptides by hydrocarbon α-helix stapling based on structural information from the VapBC TA system and in vitro systematic validation led to V26-SP-8, a VapC26 activator of M. tuberculosis. This compound exhibited highly enhanced activity and cell permeability owing to the stabilizing helical propensity of the peptide. These characteristics will increase its efficacy against multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis. Similar approaches utilizing structural and biochemical information for new antibiotic targets opens a new era for developing TB therapies.

The first crystal structure of a type II toxin–antitoxin complex structure of Klebsiella pneumoniae at 2.3 Å resolution is presented. Mutational experiments and cell-growth assays confirm Arg28 and Thr51 as critical residues for MazF ribonuclease activity., Bacterial toxin–antitoxin (TA) systems correlate strongly with physiological processes in bacteria, such as growth arrest, survival and apoptosis. Here, the first crystal structure of a type II TA complex structure of Klebsiella pneumoniae at 2.3 Å resolution is presented. The K. pneumoniae MazEF complex consists of two MazEs and four MazFs in a heterohexameric assembly. It was estimated that MazEF forms a dodecamer with two heterohexameric MazEF complexes in solution, and a truncated complex exists in heterohexameric form. The MazE antitoxin interacts with the MazF toxin via two binding modes, namely, hydro­phobic and hydro­philic interactions. Compared with structural homologs, K. pneumoniae MazF shows distinct features in loops β1–β2, β3–β4 and β4–β5. It can be inferred that these three loops have the potential to represent the unique characteristics of MazF, especially various substrate recognition sites. In addition, K. pneumoniae MazF shows ribonuclease activity and the catalytic core of MazF lies in an RNA-binding pocket. Mutation experiments and cell-growth assays confirm Arg28 and Thr51 as critical residues for MazF ribonuclease activity. The findings shown here may contribute to the understanding of the bacterial MazEF TA system and the exploration of antimicrobial candidates to treat drug-resistant K. pneumoniae.

Advances in microscale 3D cell culture systems have helped to elucidate cellular physiology, understand mechanisms of stem cell differentiation, produce pathophysiological models, and reveal important cell-cell and cell-matrix interactions. An important consideration for such studies is the choice of material for encapsulating cells and associated extracellular matrix (ECM). This Review focuses on the use of alginate hydrogels, which are versatile owing to their simple gelation process following an ionic cross-linking mechanism in situ, with no need for procedures that can be potentially toxic to cells, such as heating, the use of solvents, and UV exposure. This Review aims to give some perspectives, particularly to researchers who typically work more with poly(dimethylsiloxane) (PDMS), on the use of alginate as an alternative material to construct microphysiological cell culture systems. More specifically, this Review describes how physicochemical characteristics of alginate hydrogels can be tuned with regards to their biocompatibility, porosity, mechanical strength, ligand presentation, and biodegradability. A number of cell culture applications are also described, and these are subcategorized according to whether the alginate material is used to homogeneously embed cells, to micropattern multiple cellular microenvironments, or to provide an outer shell that creates a space in the core for cells and other ECM components. The Review ends with perspectives on future challenges and opportunities for 3D cell culture applications.

Toxin&ndash, antitoxin (TA) systems are prevalent in bacteria and are known to regulate cellular growth in response to stress. As various functions related to TA systems have been revealed, the importance of TA systems are rapidly emerging. Here, we present the crystal structure of putative mRNA interferase BC0266 and report it as a type II toxin MazF. The MazF toxin is a ribonuclease activated upon and during stressful conditions, in which it cleaves mRNA in a sequence-specific, ribosome-independent manner. Its prolonged activity causes toxic consequences to the bacteria which, in turn, may lead to bacterial death. In this study, we conducted structural and functional investigations of Bacillus cereus MazF and present the first toxin structure in the TA system of B. cereus. Specifically, B. cereus MazF adopts a PemK-like fold and also has an RNA substrate-recognizing loop, which is clearly observed in the high-resolution structure. Key residues of B. cereus MazF involved in the catalytic activity are also proposed, and in vitro assay together with mutational studies affirm the ribonucleic activity and the active sites essential for its cellular toxicity.

Surface modification using alginic acid and its salt, alginate (Alg), has attracted much attention owing to its potential applications in various fields, including tissue engineering, drug delivery, antiplatelet surface preparation, and energy-storage technologies. In these applications, efficient immobilization of Alg on the solid surface is required because the delamination of the surface-bound Alg eventually leads to a significant decrease in its function. Therefore, much effort has been made to introduce Alg onto solid surfaces in a stable manner. Despite recent advances, existing methods for immobilizing Alg on surfaces have some limitations: (i) derivatization of Alg is typically also required and (ii) these methods only function under specific reaction conditions. Herein, we report a Zr(IV)-mediated strategy to immobilize Alg on solid surfaces. We demonstrate efficient Alg grafting onto carboxyl-, catechol-, polydopamine-, and tannic acid-functionalized surfaces via Zr(IV)-mediated cross-linking reactions. This strategy yields Alg multilayers that suppress fibroblast and platelet adhesion onto the solid surfaces. Furthermore, we show that the Alg multilayers can be selectively constructed on specific sites of solid surfaces. Given its ease of use and the wide selection of available carboxyl polymers, the current strategy is expected to be a useful tool for preparing functional polymer films for various applications.

Mussel-inspired surface chemistry, in which catechol derivatives play an important role, has garnered extensive research interest owing to material-independent surface coating capability and easy implementation to a wide range of applications. Generally, sequential reactions comprising catechol oxidation, intramolecular reaction of oxidized catechols with nucleophiles, and intermolecular assembly result in polymers that can adhere to many diverse surfaces. Although amines and thiols have similar reactivity toward oxidized catechols, most studies have been conducted with catechol and amine groups as essentials. Surface coating with catechol-thiol has not been investigated. In this study, we show that 4-(2-mercapto-ethyl)-benzene-1,2-diol (catechol-thiol) can serve as a surface coating agent in the presence of a strong oxidant. A wide range of materials are coated with catechol-thiol, and an additional grafting of the functional molecules onto the surface is also performed through well-established thiol chemistry, Michael addition, and thiol-ene reaction.

Consumption of sunset yellow (SY) above a certain concentration through food products may leads to adverse health issues. Therefore, it is imperative to develop technologies for rapid and selective detection of SY. Herein, a flower-like reduced graphene oxide (rGO)-graphitic carbon nitride (g-CN)/ZnO-Au nanoparticle (NPs) has been prepared and utilized for the specific detection of SY. The fabricated rGO-g-CN/ZnO-AuNPs composite was characterized and investigated by XRD, FTIR, SEM, TEM, XPS, EIS, and voltammetry techniques. Characterization techniques elucidated the deposition of ZnO-AuNPs on to the rGO-g-CN and successful fabrication of rGO-g-CN/ZnO-AuNPs composite. rGO-g-CN/ZnO-AuNPs composite possesses excellent catalytic activity for the oxidation of SY. Developed rGO-g-CN/ZnO-AuNPs sensor exhibits LOD of 1.34 nM for SY concentrations ranging from 5 to 85 nM. Noteworthily, the sensor has been successfully employed for the detection and recovery of SY in real-time samples. Fabricated composite opens up new avenues to develop electrochemical sensor for food safety.

We evaluated potential biomarkers in human whole saliva for the early diagnosis of oral squamous cell carcinoma (OSCC). We selected 30 candidate genes with relevance to cancer from recent reports in PubMed. Saliva samples were obtained from 34 non-tumor control and 33 OSCC patients. Real-time PCR was performed, and mRNA levels were compared. Normalized mRNA levels of six genes (NGFI-A binding protein 2 (NAB2), cytochrome P450, family 27, subfamily A, polypeptide 1 (CYP27A1), nuclear pore complex interacting protein family, member B4 (NPIPB4), monoamine oxidase B (MAOB), sialic acid acetyltransferase (SIAE), and collagen, type III, alpha 1 (COL3A1)) were significantly lower in saliva of OSCC patients. Receiver operating characteristics (ROC) analysis was used to individually evaluate the predictive power of the potential biomarkers for OSCC diagnosis. The area under the curve (AUC) values were evaluated for the OSCC vs. non-tumor groups via univariate ROC analyses, as well as multivariate ROC analyses of combinations of multiple potential biomarkers. The combination of CYP27A1 + SIAE showed a favorable AUC value of 0.84. When we divided saliva samples into two groups according to age using a 60-year cut-off, with OSCC patients and controls evaluated together, the AUC of MAOB&ndash, NAB2 was more predictive of OSCC in the under-60 group (AUC, 0.91, sensitivity, 0.92, and specificity, 0.86) than any other gene combination. These results are expected to aid the early diagnosis of OSCC, especially in patients under 60 years of age. While more studies with larger numbers of patients are necessary, our result suggest that salivary mRNA would be a potent biomarker for early OSCC diagnosis.

We synthesized a zwitterionic dopamine derivative ( ZW-DOPA) containing both catechol and amine groups, and we demonstrated an excellent marine antifouling surface by controlling the oxidation of ZW-DOPA. The oxidation was mediated by the deprotonation of catechol or the addition of an oxidant (ammonium persulfate (AP) or sodium periodate (NaIO4)). The oxidation and subsequent molecular transformation of ZW-DOPA was investigated over time by UV-vis spectroscopy. Among the different oxidation conditions tested, NaIO4-induced ZW-DOPA coating was the most efficient and successfully formed on various substrates, such as titanium dioxide, stainless steel, and nylon. Compared with uncoated substrates, ZW-DOPA-coated substrates showed high resistance to marine diatom adhesion. Considering the ease of use and substrate independence of the ZW-DOPA coating, this method shows promise as a basis for inhibiting marine fouling on a variety of substrates used in the marine industry and aquatic environments.

Several industries using gamma sterilization techniques for food safety, and long shelf-life purposes. Nuclear energy production has increased the amount of spent nuclear fuel produced, which poses risks of severe diseases in human. Cesium is one of the most hazardous material can cause human exposure to air, water, and food. The efficient removal of cesium ions (Cs+) has been emphasized using biological control strategies. In this study, we isolated a new Cs+-tolerant (100, 500, and 750 ppm) and gamma radiation resistant (1, 3, and 5 kGy) soil bacterium (CR1) from the soil around a nuclear power plant in Korea, which was identified as Exiguobacterium acetylicum CR1 by 16S rRNA sequencing. E. acetylicum CR1 was found to be resistant to high doses of gamma radiation without any loss in Cs+ tolerance or survival. Furthermore, E. acetylicum CR1 was found to act as a microbiological control agent with respect to the removal of cesium from contaminated water. Interestingly, after gamma radiation exposure, E. acetylicum CR1 developed significantly (p

Background/aim Few studies have examined the effect of 2'-hydroxycinnamaldehyde (HCA) on head and neck squamous cell carcinoma (HNSCC) cell invasion. This study examined the role of BMP7 on the anti-migration and anti-invasion activity of HCA using HNSCC cells. Materials and methods Matrigel invasion and wound healing assays were conducted to investigate cell migration or invasion. BMP7 overexpression vector or siRNA mixture was used for transient regulation of gene expression. Results HCA attenuated HNSCC cell migration and spheroids Matrigel invasion without cytotoxicity. mRNA and protein expression of BMP7 increased with HCA treatment. Exogenous BMP7 overexpression without HCA treatment attenuated Matrigel invasion of cells. Furthermore, suppression of BMP7 by siRNA alleviated the inhibitory effect of HCA on the invasion of Matrigel by the cell, indicating that BMP7 is responsible for the anti-migration effect of HCA in HNSCC cells. Conclusion HCA treatment led to a remarkable up-regulation of BMP7, which resulted in the attenuation of HNSCC cell invasion.

In this work, multifunctional Fe-aminoclay (FeAC)/carboxymethyl cellulose (CMC)/ polyhedral oligomeric silsesquioxane (POSS) composite (FeAC/CMC/POSS) with layered structure was successfully synthesized and utilized as adsorbent for the removal of cesium ions (Cs+) and cationic dyes methylene blue (MB) and chrysoidine G (CG) from aqueous solutions. The FeAC/CMC/POSS exhibit excellent adsorption capacities for Cs+ ions, MB and CG of 152, 438, and 791 mg g–1, respectively. The adsorption capacities for Cs+ ions, MB and CG are substantially greater than those of many previously reported adsorbents due to (i) the layered morphology of the composite and abundance of amino (−NH2) groups on clay surface and (ii) existence of carboxylate (−COO–) and hydroxyl (−OH–) groups on the CMC backbone, which contribute to the adsorption of large number of Cs+ ions and dye molecules through electrostatic attraction and ion-exchange process. More importantly, the incorporation of POSS increases the interlayer spacing of Fe-a...

A customized droplet-based microfluidic reactor was fabricated for the synthesis of silver nanoparticles (Ag NPs) using silver nitrate (AgNO3) and branched polyethyleneimine (BPEI) as a precursor and a reducing agent, respectively. The effects of static mixing, temperature, and the volumetric flow rates of AgNO3 and BPEI on the particle size were investigated. The use of a static mixer and the optimization of the reaction temperature enhanced the monodispersity of the Ag NPs. In addition, the size of the Ag NPs was manipulated by changing the flow rate ratio of AgNO3 to BPEI at 60 °C for 60 min.

Streptococcus pneumonia has attracted increasing attention due to its resistance to existing antibiotics. TA systems are essential for bacterial persistence under stressful conditions such as nutrient deprivation, antibiotic treatment, and immune system attacks. In particular, S. pneumoniae expresses the HicBA TA gene, which encodes the stable HicA toxin and the labile HicB antitoxin. These proteins interact to form a non-toxic TA complex under normal conditions, but the toxin is activated by release from the antitoxin in response to unfavorable growth conditions. Here, we present the first crystal structure showing the complete conformation of the HicBA complex from S. pneumonia. The structure reveals that the HicA toxin contains a double-stranded RNA-binding domain that is essential for RNA recognition and that the C-terminus of the HicB antitoxin folds into a ribbon-helix-helix DNA-binding motif. The active site of HicA is sterically blocked by the N-terminal region of HicB. RNase activity assays show that His36 is essential for the ribonuclease activity of HicA, and nuclear magnetic resonance (NMR) spectra show that several residues of HicB participate in binding to the promoter DNA of the HicBA operon. A toxin-mimicking peptide that inhibits TA complex formation and thereby increases toxin activity was designed, providing a novel approach to the development of new antibiotics.

Here, we designed and synthesized a recoverable multifunctional adsorbent using a microfluidic reaction system and evaluated the removal performance of the smart adsorbent toward radioactive cesium as a model sample. Prussian blue-laden magnetic micro-adsorbents (PB-MNPs-MAs) with uniform morphology and monodispersity were generated via two-step sequential procedures using a glass capillary microfluidic system, followed by chemical co-precipitation with a high production rate. The cesium removal efficacy of the PB-MNPs-MAs was analyzed based on Langmuir and Freundlich isotherms by controlling adsorption parameters such as adsorbent size, initial cesium concentration, and contact time. The adsorption isotherm of the PB-MNPs-MAs was better fitted to the Langmuir model with a maximum cesium adsorption capacity of 58.73 mg g−1, which was 40% higher than that of macro-adsorbents in a dynamic magnetic field. This result can be attributed to their large specific area, which increased the kinetic rate of cesium adsorption and achieved saturation within 20 min. Additionally, the PB-MNPs-MAs were recovered from wastewater within 5 s under a static magnetic field, indicating their great potential for magnetic actuation. We believe that our PB-MNPs-MAs can encapsulate nano-functional adsorbents and prevent actuation, making them promising for environmental remediation and especially for removal of radionuclides.

We describe a facile, economic, and environment friendly green method for simultaneous detection of palladium ions (Pd2+) and recovery Pd nanoparticles (Pd NPs) from wastewater through a non-toxic gamma-irradiation based reduction reaction. Basic orange 2 (BO), an azo dye, is used as a sensing probe in Pd2+ detection and acts as a stabilizing agent in the recovery of monodispersed small Pd NPs. The presence of Pd2+ in waste water was easily observed by naked eye through the color change from yellow to red upon adding the Basic orange 2. More importantly, Pd forms a square-planar structured complex with Pd2+ which aids the development of smaller and monodispersed Pd NPs during radiolytic reduction. The size control mechanism during the recovery of Pd NPs was ascertained by varying the intensity of gamma-ray (from 10 to 50 kGy) and initial concentrations of Pd2+ (from 20 to 100 ppm). We are able to control the size of Pd NPs from 5 to 400 nm by irradiating gamma-ray doses from 1 and 50 kGy, as evident from UV-vis absorption spectra (UV-vis) and transmission electron microscopy (TEM) images. About 15 nm colloidal Pd NPs were formed at 10 kGy gamma-irradiation, and various sizes of aggregates, which may be attributed to Ostwald ripening crystal growth, were observed in the irradiation condition of 20 to 50 kGy. Further, the size of the recovered Pd NPs increases as the Pd2+ concentration increased, due to the increase in the ion association rate. Our proposed green method is a promising strategy that can easily detect Pd2+ from waste water and recover Pd NPs in desired size and morphology.

Sung-Chan Jang,1,2,* Sung-Min Kang,1,* Jun Young Lee,3,* Seo Yeong Oh,1 AT Ezhil Vilian,4 Ilsong Lee,1,2 Young-Kyu Han,4 Jeong Hoon Park,3 Wan-Seob Cho,5,* Changhyun Roh,2,6 YunSuk Huh1 1Department of Biological Engineering, Biohybrid Systems Research Center (BSRC), Inha University, Incheon, 2Biotechnology Research Division, 3Radiation Instrumentation Research Division, Advanced Radiation Technology Institute (ARTI), Korea Atomic Energy Research Institute (KAERI), Jeongeup, 4Department of Energy and Materials Engineering, Dongguk University, Seoul, 5Laboratory of Toxicology, Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan, 6Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology (UST), Daejeon, Republic of Korea *These authors contributed equally to this work Introduction: Positron emission tomography (PET) tracers has the potential to revolutionize cancer imaging and diagnosis. PET tracers offer non-invasive quantitative imaging in biotechnology and biomedical applications, but it requires radioisotopes as radioactive imaging tracers or radiopharmaceuticals. Method: This paper reports the synthesis of 18F-nGO-PEG by covalently functionalizing PEG with nano-graphene oxide, and its excellent stability in physiological solutions. Using a green synthesis route, nGO is then functionalized with a biocompatible PEG polymer to acquire high stability in PBS and DMEM. Results and discussion: The radiochemical safety of 18F-nGO-PEG was measured by a reactive oxygen species and cell viability test. The biodistribution of 18F-nGO-PEG could be observed easily by PET, which suggested the significantly high sensitivity tumor uptake of 18F-nGO-PEG and in a tumor bearing CT-26 mouse compared to the control. 18F-nGO-PEG was applied successfully as an efficient radiotracer or drug agent in vivo using PET imaging. This article is expected to assist many researchers in the fabrication of 18F-labeled graphene-based bio-conjugates with high reproducibility for applications in the biomedicine field. Keywords: graphene oxide, nanocomposite, imaging, radiotracer

Agricultural food crop yields have increased enormously due to the implementation of chemical pesticides; however, their excessive and uncontrolled use has led to food contamination, as well as environmental, aquatic, and agricultural pollution. Therefore, on-site monitoring of pesticide residues in agricultural food products is crucial to ensure global food and environmental safety. Conventional pesticide detection strategies are time-consuming and unsuitable for on-site or on-field detection of pesticides. Among the current approaches for field detection of pesticides, including colorimetric, non-colorimetric, electrochemical, and optical sensing strategies, colorimetric sensing strategies exhibit the most promising potential for the on-site detection of pesticide residues due to their quick detection, easy fabrication, and high selectivity and sensitivity, in addition to being readable by the naked eye. Nonetheless, although pesticide quantification methods have been extensively described in the literature, only a few studies have conducted on-site pesticide residue analyses. Therefore, this study provides a comprehensive overview of the major advances in colorimetric sensing approaches based on nanoparticle aggregation, label-free hydrogel particles, lateral flow immunoassays (LFAs), integrated digital readers, portable field detection, and paper-based sensors for the on-site detection of pesticide residues in food crops. Moreover, this review also compares the analytical performances of the aforementioned strategies and discusses the new horizons, perspectives, and challenges associated with the development of portable devices. Therefore, we believe that this review provides important insights that might serve as the basis for the fabrication of novel colorimetric sensors with applicability in materials science, environmental science, food science, nanoscience, and biotechnology.

In this study, we have synthesized N-doped graphene (NG) supported ternary PtRuFe nanocatalyst with size ranging from 2 to 3 nm using microwave-assisted polyol method and evaluated its electrochemical activity towards methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) in direct methanol fuel cell (DMFC) and proton exchange membrane fuel cell (PEMFC), respectively. The as-prepared bifunctional PtRuFe/NG catalyst exhibited excellent electrocatalytic activity towards both MOR and ORR. During MOR, the PtRuFe/NG catalyst showed the stronger CO tolerance, lower onset potential, and higher methanol oxidation current than that of its un-doped counterpart (PtRuFe/rGO). In ORR, the catalyst exhibited higher oxygen reduction current with four electron transfer. The maximum power density delivered by PEMFC and DMFC using PtRuFe/NG were 870 and 112 mW cm−2, respectively, which are 25% higher than that of its un-doped counterpart. Also PtRuFe/NG showed 2- to 3-fold improvement in MOR, ORR, PEMFC and DMFC performances as compared with previously reported values of mono-, bi-, and tri-metallic catalysts supported on NG and other carbon substrates. The enhanced electrochemical activity may be attributed to the synergetic effect of nitrogen-doping along with the bi-functional and ligand effects of alloying low-cost Fe with Pt and Ru. The bifunctional ternary PtRuFe nanocatalysts supported on N-doped graphene has excellent potential to catalyze both MOR and ORR with remarkable reduction in the processing cost of fuel cells which is the primary problem facing the commercialization of fuel cells.

The authors describe an electrochemical sensor for nitrite that is based on the use of a screen printed carbon electrode modified with palladium nanoparticles and an amino-functionalized metal-organic framework. The morphology and properties of the resulting material were examined by X-ray photoelectron spectroscopy, X-ray diffraction, thermogravimetry, FTIR spectroscopy and transmission electron microscopy. Nitrite was chosen as a model analyte to evaluate the electron transfer performance of the modified SPCE. Its preparation conditions were optimized. The response to nitrite was studied via cyclic voltammetry, linear sweep voltammetry, and square wave voltammetry. Under the optimal conditions, the oxidation current (typically measured at −0.86 V vs Ag/AgCl) increases linearly in the 5 to 150 nM nitrite concentration range, and the detection limit is 1.3 nM. The sensor was applied to the detection of nitrite in (spiked) sausage and pickle samples. It is highly selective to nitrite in the presence of high concentrations of other electro-active compounds, stable, and well reproducible. In our perception, the sensor presented here reveals the large potential of MOF-based hybrid materials for use as an electrode material.

The effect of oxytocin (OXT) on cancer invasion is controversial. Few studies have examined the effect of early growth response-1 (EGR1) on the invasion of head and neck squamous cell carcinoma (HNSCC). Here, we evaluated how EGR1 affects HNSCC cell migration through the molecular mechanism of OXT in exerting anti-invasion activity. Matrigel invasion and wound-healing assays were used to measure the in-vitro cell migration. The molecular mechanism of OXT was assessed by knockdown or overexpression of EGR1 in HNSCC cells. Three-dimensional (3-D) spheroids formation, followed by the image analysis for quantification was performed. OXT at 500 nmol/l increased mRNA and protein expression of E-cadherin without cytotoxicity. OXT upregulated mRNA and protein expression of EGR1 in 6 h. p53, phosphatase and tensin, and p21 expression was increased in an EGR1-dependent manner with OXT treatment. In addition, OXT significantly downregulated 3-D spheroids' formation according to spheroids' number and size. Our data showed that OXT downregulated HNSCC cell migration by EGR1 upregulation. OXT inhibited spheroids' formation of HNSCC cells under 3-D culture conditions.

Cesium (Cs), a radioactive contaminant of the ecosystem, causes a major risk to human health and environments. Till now, the cesium sensor fabrication methods have been reported with the usage of expensive chemicals that are complex and time-consuming. In this work, we have fabricated a paper-based colorimetric device impregnated with a chrysoidine G (CG) as chemo-indicator which is simple, rapid, low-cost, and portable using a naked-eye quantitative technique for the detection and monitoring of inactive cesium in environmental analysis. This chemo-indicator is designed to exhibit a powerful detection capability featuring high selectivity and sensitivity to inactive Cs, by means of color discrimination from light yellow to red orange. Interestingly, a portable smart phone camera, which determined the relative red/green/blue (RGB) values within 3 s, provided us with further information on environmental pollution. Using our new colorimetric reusable sensor (CRS) platform, the CRS shows excellent detection linearity (R2 = 0.99) of inactive Cs from the contaminated water. Our results will pave the way for portable and versatile sensors and, in turn, for the detection and monitoring of toxic inactive cesium in contaminated water samples.

Rationale: The present study reports the multifunctional anticancer activity against B16F10 melanoma cancer cells and the bioimaging ability of fluorescent nitrogen-phosphorous-doped carbon dots (NPCDs). Methods: The NPCDs were synthesized using a single-step, thermal treatment and were characterized by TEM, XPS, fluorescence and UV-Vis spectroscopy, and FTIR analysis. The anticancer efficacy of NPCDs was confirmed by using cell viability assay, morphological evaluation, fluorescent live-dead cell assay, mitochondrial potential assay, ROS production, RT-PCR, western-blot analysis, siRNA transfection, and cellular bioimaging ability. Results: The NPCDs inhibited the proliferation of B16F10 melanoma cancer cells after 24 h of treatment and induced apoptosis, as confirmed by the presence of fragmented nuclei, reduced mitochondrial membrane potential, and elevated levels of reactive oxygen species. The NPCDs treatment further elevated the levels of pro-apoptotic factors and down-regulated the level of Bcl2 (B-cell lymphoma 2) that weakened the mitochondrial membrane, and activated proteases such as caspases. Treatment with NPCDs also resulted in dose-dependent cell cycle arrest, as indicated by reduced cyclin-dependent kinase (CDK)-2, -4, and -6 protein levels and an enhanced level of p21. More importantly, the NPCDs induced the activation of autophagy by upregulating the protein expression levels of LC3-II and ATG-5 (autophagy-related-5) and by downregulating p62 level, validated by knockdown of ATG-5. Additionally, owing to their excellent luminescence property, these NPCDs were also applicable in cellular bioimaging, as evidenced by the microscopic fluorescence imaging of B16F10 melanoma cells. Conclusion: Based on these findings, we conclude that our newly synthesized NPCDs induced cell cycle arrest, autophagy, and apoptosis in B16F10 melanoma cells and presented good cellular bioimaging capability.

In this study, highly biocompatible three-dimensional hierarchically porous activated carbon from the low-cost silver grass (Miscanthus sacchariflorus) has been fabricated through a facile carbonization approach and tested it as bioanode in microbial fuel cell (MFC) using Escherichia coli as biocatalyst. This silver grass-derived activated carbon (SGAC) exhibited an unprecedented specific surface area of 3027 m2 g−1 with the coexistence of several micro-, meso-, and macropores. The synergistic effect from pore structure (macropores — hosting E. coli to form biofilm and facilitates internal mass transfer; mesopores — favors fast electron transfer; and micropores — promotes nutrient transport to the biofilm) with very high surface area facilitates excellent extracellular electron transfer (EET) between the anode and biofilm which resulted in higher power output of 963 mW cm−2. Based on superior biocompatibility, low cost, environment-friendliness, and facile fabrication, the proposed SGAC bioanode could have a great potential for high-performance and cost-effective sustainable MFCs.

A facile approach to enhancing the blood compatibility of solid surfaces based on ZrIV -heparin complexation is reported. Solid surfaces are pretreated with tannic acid (TA)/ZrIV complexes. Heparin is then deposited on the surface through a spin-coating process and fixed by a ZrIV -mediated crosslinking reaction. Using this approach, TA/ZrIV /heparin complex multilayers that are highly resistant to human platelet adhesion are formed on various substrates including metal, metal oxides, ceramics, and synthetic polymers. This approach presents a sustainable way for the immobilization of heparin onto surfaces because it does not require any derivatization of heparin molecule as well as time-consuming processes.

The original version of this article unfortunately missed Prof. A.T. Ezhil Vilian’s project number in Acknowledgements. The missing project number is 2017R1D1A1B03034977.

In this research, we successfully synthesized a reduced graphene oxide/tin oxide (rGO/SnO

Spinal muscular atrophy (SMA) is caused by the mutation or deletion of the survival motor neuron 1 (SMN1) gene. Only ∼10% of the products of SMN2, a paralogue of SMN1, are functional full-length SMN (SMN-FL) proteins, whereas SMN2 primarily produces alternatively spliced transcripts lacking exon 7. Reduced SMN protein levels in SMA patients lead to progressive degeneration of spinal motor neurons (MNs). In this study, we report an advanced platform based on an SMN2 splicing-targeting approach for SMA drug screening and validation using an SMN2 splicing reporter cell line and an in vitro human SMA model through induced pluripotent stem cell (iPSC) technology. Through drug screening using a robust cell-based luciferase assay to quantitatively measure SMN2 splicing, the small-molecule candidate compound rigosertib was identified as an SMN2 splicing modulator that led to enhanced SMN protein expression. The therapeutic potential of the candidate compound was validated in MN progenitors differentiated from SMA patient-derived iPSCs (SMA iPSC-pMNs) as an in vitro human SMA model, which recapitulated the biochemical and molecular phenotypes of SMA, including lower levels of SMN-FL transcripts and protein, enhanced cell death, and reduced neurite length. The candidate compound exerted strong splicing correction activity for SMN2 and potently alleviated the disease-related phenotypes of SMA iPSC-pMNs by modulating various cellular and molecular abnormalities. Our combined screening platform representing a pMN model of human SMA provides an efficient and reliable drug screening system and is a promising resource for drug evaluation and the exploration of drug modes of action.

In this study, we developed a modular micronozzle system that can control the flow of fluid based on centrifugal force and synthesize functional alginate microspheres with various structures and sizes. Our method is to fabricate a programmable microreactor that can be easily manufactured without the conventional soft-lithography process using various sequences of the micronozzles with various inner diameters. To overcome the obstacles of pump-based microfluidic devices that need to be precisely controlled, we designed the programmable microreactor to be driven under centrifugal force with a combination of micronozzles, thus enabling the mass production of various functional alginate microspheres within a few minutes. The programmable microreactor designed through the arrangement of the modular micronozzles enables the formation of various types of alginate microspheres such as core-shell, Janus, and particle mixture. These materials are controlled to a size from 400 µm to 900 µm. In addition, our platform is used to generate pH-responsive smart materials, and to easily control various sizes, shapes, and compositions simultaneously. By evaluating the release process of model drugs according to the pH change, the possibility of drug delivery application is confirmed. We believe that our method can contribute to development of biomaterials engineering that has been limited by the requirement of sophisticated devices, and special skills and/or labor.