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2D-Ti 3 C 2 T x MXene nanosheets intercalated with sodium ions (SI-Ti 3 C 2 T x ) were synthesized and utilized in simultaneous adsorption and electrochemical regeneration with ciprofloxacin (CPX). The primary focus of this study is to investigate the long-term stability of SI-Ti3C2Tx MXene and to propose the underlying regeneration mechanisms. The successful synthesis of Ti 3 AlC 2 , Ti 3 C 2 T x MXene, and SI-Ti 3 C 2 T x MXene was confirmed using X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. Electrochemical regeneration parameters such as charge passed, regeneration time, current density, and electrolyte composition were optimized with values of 787.5 C g -1 , 7.5 min, 10 mA cm -2 , and 2.5w/v% sodium chloride, respectively, enabling the complete regeneration of the SI-Ti 3 C 2 T x MXene. In addition, the electrochemical regeneration significantly enhanced CPX removal from the SI-Ti 3 C 2 T x MXene owing to partial amorphization, disorderliness, increased functional groups, delamination, and defect creation in the structure. Thus, the synthesized nano-adsorbent has proven helpful in practical water treatment with optimized electrochemical regeneration processes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Sodium alginate (SA)-laden two-dimensional (2D) Ti 3 C 2 T x MXene (MX) and MIL-101(Fe) (a type of metal-organic framework (MOF)) composites were prepared and used for the removal of naproxen (NPX), following the adsorption and electrochemical regeneration processes. The fixed-bed adsorption column studies were also conducted to study the process of removal of NPX by hydrogels. The number of interactions via which the MX-embedded SA (MX@SA) could adsorb NPX was higher than the number of pathways associated with NPX adsorption on the MIL-101(Fe)-embedded SA (MIL-101(Fe)@SA), and the MX and MIL-101(Fe) composite embedded SA (MX/MIL-101(Fe)@SA). The optimum parameters for the electrochemical regeneration process were determined: charge passed and current density values were 169.3 C g -1 and 10 mA cm -2 , respectively, for MX@SA, and the charge passed and current density values were 16.7 C g -1 and 5 mA cm -2 , respectively, for both MIL-101(Fe)@SA and MX/MIL-101(Fe)@SA. These parameters enabled excellent regeneration, consistent over multiple adsorption and electrochemical regeneration cycles. The mechanism for the regeneration of the materials was proposed that the regeneration of MX@SA and MIL-101(Fe)@SA involved the indirect electrooxidation process in the presence of OH radicals, and the regeneration of MX/MIL-101(Fe)@SA involved the indirect oxidation process in the presence of active chlorine species., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Binder-free two-dimensional mesh-like structure of nickel-zinc metal-organic framework on in-situ-coated carbon cloth (Ni-Zn MOF/CC) and Ni-Zn MOF powder were developed via a solvo-hydrothermal reaction for electrochemical storage application. The electrochemical properties of these electrodes show that the electrodes self-assembled on carbon cloth substrates exhibit remarkably excellent performance. The Ni-Zn MOF/CC electrode exhibited a capacitance of 653.54 F/g at 1 A/g through a capacity retaining of 87.65% after 10000 cycles. Furthermore, the Ni-Zn MOF//AC coin-cell asymmetric supercapacitor device (CASD) exhibited remarkable energy and power densities of 54.31 Wh/kg and 825 W/kg, respectively, with adequate capacitance retention up to 94.63% over 5000 cycles at 1.5 V. The CASD also exhibited a significant power density of 4950 W/kg at 19.67 W h/kg, which suggests that these in-situ developed MOF-based electrodes may discover application in energy storage devices., (© 2022 Wiley-VCH GmbH.)

Herein, mixed-phase BiFeO 3 /Fe 2 O 3 (BF-M) nanocomposite has been successfully prepared in a simple single-step synthetic strategy and its structural, physicochemical and magnetic properties have been characterized. The performance of as-synthesized mixed-phase BF-M catalyst has been investigated in photoelectrochemical (PEC) water oxidation and photocatalytic dye degradation analysis by comparing with the partials Fe 2 O 3 with BiFeO 3 (BF-P). The BF-M photocatalyst has degraded 95.7% of the rhodamine B (RhB) dye while BF-P has degraded 82.1% in 80 min. In addition, the BF-M electrode exhibited 0.57 mA cm -2 photocurrent density which was 1.83 times higher than the BF-P electrode (0.31 mA cm -2 ), signifying that the formation of a mixed-phase nanostructure interface is advantageous in enhancing light absorption capacity and reducing the rate of electron-hole recombination., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Advanced functional materials for photocatalytic hydrogen (H 2 ) generation using abundant solar energy are the core of new and renewable energy research. In this paper, we report the in-situ deposition of platinum quantum-sized particles (Pt QDs) on bismuth oxybromide (BBr) 3D marigold flowers with exposed (101)/(110) facets (i.e. BBr-Pt) hierarchies prepared by a simple solvo-thermal method acting as a surfactant/structure stabilizer in the presence of CTAB. Synthesized samples were characterized by a series of analytical techniques. Intimate contact as demonstrated by HRTEM, effect of Pt loading in 3D-BiOBr nanostructure on photocatalytic H 2 production and crystal violet (CV) dye degradation rate under white LED light irradiation was studied. This was greatly improved by loading Pt QDs on BBr, the latter showing the highest photocatalytic activity for BBr-2Pt nanostructure, due to the synergistic effect of quantum-sized Pt nanoparticles and exposed ((101) and (110) planes). The BBr-2Pt nanostructure photocatalysts showed highest H 2 generation of 320.69 μmol g -1 , which is 142 folds larger than bare BBr (2.26 μmol g -1 )., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Although a DNA-immobilized packed-column (DNA-packed column), which relies on sequence-dependent interactions of target DNA or mRNA (in the mobile phase) with DNA probes (on the silica particle) in a continuous flow process, could be considered as an alternative platform for quantitative analysis of specific DNA to DNA chip methodology, the performance in practice has not been satisfactory. In this study, we set up a more efficient quantitative analysis system based on a DNA-packed column by employing a temperature-gradient strategy and DMSO-containing mobile phase. Using a temperature-gradient strategy based on T(m) values of probe/target DNA hybridizations and DMSO (5%)-containing mobile phase, we succeeded in the quantitative analysis of a specific complementary target distinguishable from non-complementary DNA oligomers or other similar DNA samples. In addition, two different target DNA oligomers even with similar T(m) values were separated and detected quantitatively by using a packed column carrying two different DNA probes.

A DNA-immobilized open tubular capillary column (DNA-immobilized OTC) system was developed for analysis and separation of target DNA oligomers. By combining the DNA-immobilized OTC column with a nano/micro-flow pump and a high-sensitivity UV detector, we succeeded in small-scale selective detection of target DNA oligomers (> 0.02 pmol). We designed a temperature-gradient strategy for the efficient separation of target DNA.

DNA chips prepared on a flat glass surface have unavoidable drawbacks when used for quantitative analysis. In an attempt to overcome this problem, we constructed an HPLC-type system suitable for quantitative analysis that enables base sequence- and T (m)-dependent DNA oligomer separation in a flow system. A small open tubular capillary column (300-mm x 100-microm I.D.) was used. The DNA oligomers used as probes had an amino group at the 5'-end and were immobilized on the inner silica surface of the capillary column which had been sequentially treated with 3-aminopropyltriethoxysilane, butyltrimethoxysilane, and disuccinimidylglutarate. Using the combination of probe-immobilized column placed in a column oven equipped with temperature gradient function, a nano-flow-controllable pump, a small sample-loading injector, and a capillary-fitted UV detector, we succeeded in separating complementary and non-complementary DNA oligomers in specific and quantitative modes. We also designed a temperature gradient strategy for efficient separation of target DNA oligomers in DNA mixture samples. Using a column carrying two different probes with similar T (m) values, their complementary target DNA oligomers were also separated and detected. The developed DNA open tubular capillary column system investigated in the present study could be further improved as an alternative tool to DNA chips to be used for the quantitative analysis of DNA or mRNA samples.

Amine-modified oligodeoxynucleotides (AMO) are commonly used probe oligodeoxynucleotides for DNA microarray preparation. Two methods are currently used for AMO preparation--use of amine phosphoramidites protected by acid-labile monomethoxytrityl (MMT) groups or alkali-labile trifluoroacetyl (TFA) groups. Because conventional AMO preparation procedures have defects, for example stringent acidic conditions are required for deprotection of MMT and hydrophobic purification cannot be used for TFA-protected amino groups, conventional preparation of AMO is unlikely to result in the expected outcome. In this paper a method of AMO synthesis using modified H-phosphonate chemistry is suggested. An aliphatic diamine is coupled with a phosphonate group forming a phosphoramidate linkage to the last internucleotide phosphate of oligodeoxynucleotides. In this method dimethoxytrityl (DMT) purification steps are used and stringent acid deprotection is not required to obtain the AMO. Although the method could lead to formation of AMO diastereomers, melting-temperature and CD analysis showed for two AMO that DNA duplex formation was the same as when normal oligodeoxynucleotides were used. Also, when these AMO were used as probes for DNA microarrays the immobilization efficiency was similar to that for AMO probes prepared by conventional means using an amino-modifier unit. The hybridization performance of these AMO was better than for those prepared conventionally. The procedures suggested would be useful for preparation of efficient AMO for fabrication of DNA microarrays and DNA-based nanoparticle systems.

Oxanine (Oxa), which is one of the major products generated from guanine by nitrosative oxidation and is as long-lived as Gua in DNA, has been thought to be one of the major causes for NO-induced DNA damage. In the present study, using several synthetic Oxa-containing oligodeoxynucleotides, biophysical stability and enzymatic recognition of Oxa was investigated in DNA strands. It was found that Oxa did not mediate marked distortion in the whole DNA structure although Oxa pairing with 4 normal bases decreased thermal stability of the DNA duplexes compared to Gua:Cyt base pair. Regarding the responses of the DNA-relevant enzymes to Oxa, it was determined that Oxa was recognized as Gua except that DNA polymerases incorporated Thy as well as Cyt opposite Oxa. These results imply that Oxa tends to behave as a kind of naturally occurring base, Gua and therefore, would be involved in the genotoxic and cytotoxic threats of NO in cellular system.

DNA microarray has become one of the most indispensable tools for genome analysis, medical diagnosis and molecular biological studies. In this study, to make DNA microarray more reliable and efficient, we employed additional silanization modification on aminoalkoxysilane-treated surface. In addition, oxanine was used as a linker of DNA probe, which does not require any chemical activation step in probe immobilization. These strategies were practically convenient in DNA microarray fabrication, and the newly developed system showed enhanced stability for the immobilized DNA probes that could be useful for quantitative analysis.

Oxanine having an O-acylisourea structure was explored to see if its reactivity with amino group is useful in DNA microarray fabrication. By the chemical synthesis, a nucleotide unit of oxanine (Oxa-N) was incorporated into the 5'-end of probe DNA with or without the -(CH2)n- spacers (n = 3 and 12) and found to immobilize the probe DNA covalently onto the NH2-functionalized glass slide by one-pot reaction, producing the high efficiency of the target hybridization. The methylene spacer, particularly the longer one, generated higher efficiency of the target recognition although there was little effect on the amount of the immobilized DNA oligomers. The post-spotting treatment was also carried out under the mild conditions (at 25 or 42 degrees C) and the efficiencies of the immobilization and the target recognition were evaluated similarly, and analogous trends were obtained. It has also been determined under the mild conditions that the humidity and time of the post-spotting treatment, pH of the spotting solution and the synergistic effects with UV-irradiation largely contribute to the desired immobilization and resulting target recognition. Immobilization of DNA oligomer by use of Oxa-N on the NH2-functionalized surface without any activation step would be employed as one of the advanced methods for generating DNA-conjugated solid surface.

Aminosilane-treated molecular layers on glass surfaces are frequently used as functional platforms for biosensor preparation. All the amino groups present on the surface are not available in reactive forms, because surface amino groups interact with remaining unreacted surface silanol groups. Such nonspecific interactions might reduce the efficiency of chemical immobilization of biomolecules such as DNA, enzymes, antibodies, etc., in biosensor fabrication. To improve immobilization efficiency we have used additional surface silanization with alkylsilane (capping) to convert the remaining silanol groups into Si-O-Si linkages, thereby liberating the amino groups from nonspecific interaction with the silanol groups. We prepared different types of capped amine surface and evaluated the effect of capping on immobilization efficiency by investigating the fluorescence intensity of Cy3-NHS (N-hydroxysuccinimide) dye that reacted with amino groups. The results indicate that most of the capped amine surfaces resulted in enhanced efficiency of immobilization of Cy3-NHS compared with the untreated control amine surface. We found a trend that trialkoxysilanes had greater capping effects on immobilization efficiency than monoalkoxysilanes. It was also found that the aliphatic chain of alkylsilane, which does not participate in the capping of the silanol, had an important function in enhancing immobilization efficiency. These results would be useful for preparation of an amine-modified surface platform, with enhanced immobilization efficiency, which is essential for developing many kinds of biosensors on a silica matrix.

A novel approach for immobilization of probe oligonucleotides that uses zirconium phosphate modified silica nanoparticles is proposed. The surface modification of nanoparticles was carried out in two stages. Initially binding of Zr4+ to the surface of silica nanoparticles and later treated with phosphoric acid for terminal phosphate groups. Oligonucleotide probes modified with amine group at 5'-end were strongly binds to the phosphate terminated silica nanoparticles with imidazole in presence of 0.1 mol L(-1) EDC [N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide], as phosphate groups are more reactive towards amine group. Various studies, i.e., synthesis of silica nanoparticles, their surface modification, probe immobilization, measurement of hybridization and effect of bovine serum albumin (BSA) were carried out during optimization of reaction conditions. The significant reduction in the background signal was observed by treating the probe modified silica nanoparticles with bovine serum albumin prior to hybridization. The probe modified silica nanoparticles were retained their properties and the hybridization was induced by exposure of single-stranded DNA (ssDNA) containing silica nanoparticles to the complementary DNA in solution. The decrease in the fluorescence signal for one mismatch and three mismatch was observed upon hybridization of probe with target DNAs, while there was no response for the random target ssDNA under the same experimental conditions. The intensity of fluorescence signal was linear to the concentration of target DNA ranging from 3.9 x 10(-9) to 3.0 x 10(-6)mol L(-1). A detection limit of 1.22 x 10(-9) mol L(-1) of oligonucleotides can be estimated. The proposed hybridization assay is simple and possesses good analytical characteristics and it can provide an effective and efficient route in the development of DNA biosensors and biochips.

Oxanine (Oxa, O), one of the major products generated from guanine (Gua) by nitrosative oxidation has been expected as mutagenic lesion involved in NO- or HNO(2) -induced genotoxicity. Here, to elucidate the biological meaning of Oxa in DNA strands, several kinds of Oxa-containing oligodeoxynucleotides (Oxa-ODNs) were synthesized and applied to biophysical and biochemical characterization. CD and NMR analyses revealed that the conformations of all the Oxa-containing duplexes are basically B-type without causing any severe distortion in the whole DNA structure. It was also determined that restriction endonucleases recognize and cleave the specific base-sequence even when Gua was substituted by Oxa in the sequence. When Oxa-ODN was testified as substrates for other DNA-relevant enzymes, the enzymatic functions were not largely affected by Oxa.

Quantitative separation of target DNA molecules was performed by DNA-arrayed silica capillary column on the basis of base pairing interaction of nucleic acids. We prepared DNA-arrayed silica capillary column by conjugating 5'-amniohexyl oligonucleotide (probe) on inner surface of the capillary column pre-treated with 3-aminopropyltriethoxysilane (APS) and disuccinimidyl glutarate (DSG) cross-linker. Sufficient resolution was observed by controlling of target-DNAs concentration, salt gradients, and temperature gradients. Finally, we succeeded to separate two different DNA targets even with same melting temperature according to their own concentrations. These results would be useful for developing quantitative analysis of cDNA, which is related to mRNA levels in biological sample.

Oligodeoxynucleotide probes tethered with amine linkers are commonly used for development of DNA based biosensor tools for studying gene expression and biological assays. However, the current preparation methods for synthesizing amine tethered probes often show defects during acid deprotection and during hydrophobic purification with the amine linker protecting groups. Here, we developed a prospective preparation method of using modified H-phosphonate chemistry to prepare amine tethered oligonucleotide probes. The present developed method will be helpful for preparing efficient amine tethered oligodeoxynucleotide probes that can be used in DNA biosensor applications.