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[Display omitted] Copper-based Fenton-like agents have the ability to convert weakly oxidizing H 2 O 2 into highly oxidizing hydroxyl radicals (·OH) at tumor sites during chemodynamic therapy (CDT). In this study, the interfacial attraction properties between the negatively charged OCP− in sodium phosphathynolate (NaOCP) and the positively charged environment inside the lumen of halloysite nanotubes (HNTs) were utilized to synthesize Cu 3-x P nanoparticles in situ within the HNTs. The study investigated the chemical composition, morphology, and structure of Cu 3-x P@HNTs. The results indicated uniform distribution of Cu 3-x P particles measuring 3–5 nm within HNTs' lumen. Experiments conducted internally and externally to cells confirmed the catalytic capability of Cu 3-x P@HNTs to oxidize H 2 O 2 to ·OH. Furthermore, CP@H-CM was synthesized by enclosing Cu 3-x P@HNTs in a cancer cell membrane, which selectively targets cancer cells. The experiments revealed the cytotoxicity of CP@H-CM on 4T1 cells. Additionally, the antitumor efficacy of CP@H-CM was evaluated in vivo through tumor recurrence experiments in mice. Moreover, the efficacy of CP@H-CM in repressing tumor growth was enhanced by incorporating infrared laser, indicating a synergistic photodynamic treatment for breast cancer. This study presents an efficacious and viable therapeutic approach to inhibit postoperative tumor reappearance. The implications of this approach are promising, particularly in the domain of tumor treatment and metastasis. [ABSTRACT FROM AUTHOR]

As the key to manufacturing large scale integrated circuits, horizontally aligned semiconducting single-walled carbon nanotube (s-SWNT) arrays play a key role in the next-generation electronic device. Though various techniques have been developed, obtaining pure s-SWNT horizontal arrays is still the greatest challenge. Here, we propose an effective and facile method to produce s-SWNT arrays from a diverse perspective by implementing photochemical chlorination on the as-grown aligned SWNT arrays. The electrical measurements demonstrate a high fraction of s-SWNTs (>98.1%) after photochlorination, and its exceptional performance as a field-effect transistor with an on-off ratio up to 3730. Meanwhile, through the well-controlled mask-assisted photochlorination, a type of metallic-semiconducting SWNT intramolecular junction with rectifying diode and non-linear transport characteristics has also been successfully obtain. Our work provides a new method for the preparation of high-purity s-SWNT arrays and SWNT intramolecular junction, which has great significance for the carbon-based nano-electronic devices in applications. [Display omitted] • Transition from m-SWNT to s-SWNT. • Selective modification to s-SWNT. • Less damage and contamination to the samples. • Convenient and simple. • Area-selected method to fabricate SWNT intramolecular junction. [ABSTRACT FROM AUTHOR]

Mixed-matrix membranes (MMMs) as one of solid sorbents for carbon dioxide (CO 2) separation face the challenge of merging efficient separation with economical preparation process using scalable raw material. Halloysite nanotubes (Hal) with unique one-dimensional gas transmission channels have great prospect in MMMs for gas separation. However, the insufficient porosity of Hal has restricted further development of CO 2 separation performances. Herein, a facile and efficient modification approach was carried out, involving successive treatments of calcination and selective leaching. The resulting nanotubes with continuous channel systems (CA-Hal) are embedded in poly(ether- block -amide) for the preparation of mixed-matrix membranes with enhanced gas transport. The performances of MMMs with modified nanotubes as inorganic fillers obtained by different modification methods (calcination, selective leaching, and a combination of calcination and selective leaching) were specifically discussed. CA-Hal with the highest specific surface area and certain surface energy has an excellent potential as inorganic fillers, which can be uniformly dispersed in the polymer matrix to form interfacial channels, preventing the particle agglomeration and producing non-selective interfacial defects. The hierarchical porous structure of CA-Hal can serve as fast gas transport channels in MMMs for efficient CO 2 diffusion and enhanced separation. The MMMs containing 5 wt% CA-Hal have demonstrated excellent CO 2 permeability (179.5 Barrer), CO 2 diffusivity (17.56 10−7 cm2·S−1) and CO 2 /N 2 selectivity (98.7). In addition, the prepared MMMs exhibits improved mechanical properties compared with the pure membrane without inorganic fillers. Manipulating the porosity and surface properties of natural halloysite (HNTs) fillers with continuous channel systems via calcination and selective acid leaching in the pebax-based mixed-matrix membranes (MMMs) could establish fast gas transport pathways in MMMs for efficient CO 2 diffusion and enhanced separation. [Display omitted] • Modified halloysite nanotubes were embedded in Pebax to fabricated mixed matrix membrane. • Manipulating filler's porosity can provide unique pathways to boost CO 2 /N 2 separation. • Dispersion of modified halloysite with more defect sites in membranes promoted gas diffusion. • Pebax-incorporated modified halloysite showed highly efficient CO 2 /N 2 separation. [ABSTRACT FROM AUTHOR]

Experimental studies of shaping a CO2 laser beam with a reflective diffractive optical element have been performed. To increase the aperture of the initial beam, we used a collimator containing a system of two plane-convex spherical ZnSe lenses. For the focal line formed with the diffractive optical element in combination with the collimator, in addition to a 1.3-fold increase in the length, a decrease in the maximum beam power density was found to occur in the laser spot. It was demonstrated that under the laser action it is possible to generate in a two-phase steel sample regions of full hardening, selective hardening, and annealing, alongside the initial structure. The formation of such structures is due to the distribution pattern of temperature fields and a difference in the cooling rate across the volume of the heat affected zone.

Stapling of peptides by intramolecular crosslinking of two neighboring amino acid side chains offers an important tool to modulate the structure and properties of peptides. In comparison to the stapling of artificially engineered peptide substrates, methods for stapling native peptides are more desirable for easier accessibility and genetic encodability. However, the existing strategy for selectivity control in the stapling of native peptides is relatively limited: the site of anchoring is often dominated by Cys, and the means for achieving the position selectivity among the same type of residues at different locations is lacking. We have developed a simple and powerful strategy for stapling native peptides at lysine residues with formaldehyde by the cooperation of nearby tyrosine or arginine residues. The stapling reactions can proceed with high efficiency and residue selectivity under mild conditions, and generate linchpins with distinct physiochemical properties. The new method for peptide stapling enables unique control of position‐selectivity for substrates bearing multiple reaction sites by reactivity that can be readily built in the peptide sequence. [ABSTRACT FROM AUTHOR]

The potential of "customizable units" to generate structural diversity for biological screenings is highlighted in this proof‐of‐concept synthesis of new peptides related to the potent antitumoral Sansalvamide A. Using L‐4‐hydroxyproline (Hyp) as a customizable unit in a linear parent peptide, an improved procedure for selective peptide modification was developed. A divergent Hyp scission‐reductive amination process was carried out, affording five linear peptides with cationic residues, and notably, an N‐alkyl moiety that affected the conformation of the peptide. After two steps (saponification and macrocyclization), sixteen differently N1‐substituted linear and cyclic peptides were obtained. For the first time, the activity of the linear and cyclic compounds was compared. Not only some linear analogs but also cyclic compounds with scarcely studied cationic residues were active against MCF7 breast cancer line. Thus, the structural diversity generated from customizable units can be valuable in drug discovery. [ABSTRACT FROM AUTHOR]

A selectively modified porous metal/carbon nanocomposite was fabricated to enhance the enrichment of low-abundance phosphopeptides from biological samples. The carbon matrix derived from the metal-organic framework provides a suitable pore size to allow the diffusion of peptides, while the deliberately modified metal nanoparticles within the pores enhance their interaction with the phosphopeptides. This nanocomposite shows extremely high enrichment selectivity for phosphopeptides in the MALDI-TOF MS detection, even when the molar ratio of α-casein digests versus bovine serum albumin digests was up to about 1:20,000. By combining such nanocomposite with nano-LC-MS/MS, 4556 unique phosphopeptides were identified with high selectivity (95.2%) from HeLa cell extracts. Furthermore, phosphopeptides from prostate tissue digests were also determined. A total of 277 and 1242 phosphopeptides were identified from normal and tumor tissues of a patient with prostate cancer, respectively. This indicates that phosphorylation and prostate cancer can be related to each other. [ABSTRACT FROM AUTHOR]

• Plasmonic Pt-Au/BiVO 4 single-crystal photocatalyst was constructed. • It was synthesized using crystal-facet engineering and selective photodeposition. • The unique photocatalyst can promote consecutive separation of photocarriers. • They are resulted from orientation transfer of BiVO 4 , Z-scheme Au/BiVO 4 , and Au-Pt. Constructing Z-scheme photocatalysts is one of the most effective technologies to enhance the photocatalytic reduction or oxidation ability in artificial photosynthesis. For the BiVO 4 photocatalyst, it usually shows limited photocatalytic ability because of the severe bulk recombination of photogenerated carriers and the poor reduction reaction of photogenerated electrons. In this paper, a novel plasmonic Z-scheme Pt-Au/BiVO 4 single-crystal photocatalyst was constructed to solve the above issues. Here, Au nanoparticles are selectively deposited on the electron-rich (0 1 0) facet of BiVO 4 , while Pt nanoparticles are selectively modified on the Au surface. Photocatalytic results indicated that the resultant Pt-Au/BiVO 4 Z-scheme photocatalyst exhibits an obviously higher photocatalytic performance than pure BiVO 4 , Au/BiVO 4 , randomly deposited BiVO 4 (Pt-Au/BiVO 4 (R)) and conventional Pt-Au/BiVO 4. More importantly, compared with the well-known Pt/BiVO 4 (2.0 wt%), the Pt-Au/BiVO 4 not only exhibits a higher photocatalytic performance, but also loads a lower amount of high-cost Pt cocatalyst. The excellent photocatalytic activity of the plasmonic Z-scheme Pt-Au/BiVO 4 photocatalyst can be attributed to the synergistic effect of crystal-facet engineering and selective loading of Pt-Au, which results in the orientation transfer of photogenerated carriers in the single-crystal BiVO 4 , the enhanced reduction power of photogenerated electrons, and the rapid oxygen-reduction reaction on Pt cocatalyst. [ABSTRACT FROM AUTHOR]

The presence of nanoparticles lowers the levels of ultrasound (US) intensity needed to achieve the therapeutic effect and improves the contrast between healthy and pathological tissues. Here, we evaluate the role of two main mechanisms that contribute to the US-induced heating of aqueous suspensions of biodegradable nanoparticles (NPs) of mesoporous silicon prepared by electrochemical etching of heavily boron-doped crystalline silicon wafers in a hydrofluoric acid solution. The first mechanism is associated with an increase of the attenuation of US in the presence of NPs due to additional scattering and viscous dissipation, which was numerically simulated and compared to the experimental data. The second mechanism is caused by acoustic cavitation leading to intense bubble collapse and energy release in the vicinity of NPs. This effect is found to be pronounced for as-called Janus NPs produced via a nano-stopper technique, which allow us to prepare mesoporous NPs with hydrophobic inner pore walls and hydrophilic external surface. Such Janus-like NPs trap air inside the pores when dispersed in water. The precise measurement of the heating dynamics in situ enabled us to detect the excessive heat production by Janus-like NPs over their completely hydrophilic counterparts. The excessive heat is attributed to the high intensity cavitation in the suspension of Janus-like NPs. The present work elicits the potential of specifically designed Janus-like mesoporous silicon NPs in the field of nanotheranostics based on ultrasound radiation.

Two selenized chitooligosaccharide (O-Se-COS and N,O-Se-COS) with different sites modification were synthesized to alleviate liver injury in vivo. Comparing to traditional COS, both selenized COS exhibited enhanced reducibility as well as antioxidant capacity in vitro. Furthermore, O-Se-COS demonstrated superior efficacy in reducing intracellular reactive oxygen species (ROS) and mitochondrial damage compared to N,O-Se-COS as its enhanced cellular uptake by the positive/negative charge interactions. Two mechanisms were proposed to explained these results: one is to enhance the enzymatic activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), which effectively scavenge free radicals; the other is to down-regulate intracellular cytochrome P450 (CYP2E1) levels, inhibiting carbon tetrachloride (CCl 4)-induced peroxidation damage. In vivo studies further demonstrated the effective alleviation of CCl 4 -induced liver injury by selenized COS, with therapeutic efficacy observed in the following order: O-Se-COS > N,O-Se-COS > COS. Finally, hemolysis and histological tests confirmed the biosafety of both selenized COS. Taken together, these finding demonstrated that selenium has the potential to improve the biological activity of COS, and precise selenylation was more conducive to achieving the synergistic effect where 1 + 1>2. [Display omitted] • O-Se-COS is synthesized by the protection/de-protection strategy. • O-Se-COS enhance cells internalization by holding abundant amino groups. • Selenizing COS relieve oxidative damage by increasing the activity of SOD and GSH-Px. • Selenizing COS reduce liver inflammatory by decreasing the levels of CYP2E1 and IL-6. • Selenizing COS reduce the toxicity of inorganic selenium. [ABSTRACT FROM AUTHOR]

Chemical modifications to proteins have wide applications. They may be used in, for example, the production of biopharmaceuticals and fluorescent probes. Despite their importance, highly regioselective chemical protein modifications are often challenging to achieve. We have developed two highly selective methods for protein acylation using poly-His tags inserted either at the N-terminus or in combination with a specific Lys residue. For this, we used an N-terminal Gly-His 6 (Gly-His tag) or the sequence His m -Lys-His n (Lys-His tag), respectively. The Gly-His tag directed the acylation to the N-terminal N α -amine when reacted with 4-methoxyphenyl esters to yield stable conjugates. Next, the Lys-His tag was developed to allow modifications at the C-terminus or in loop regions of proteins. This gave a high selectivity of acylation of the designated Lys N ε -amine in the tag over native Lys residues in the protein under mild conditions. Here, we describe the synthesis of aromatic esters carrying different functionalities and reactivity tuning substituents on the phenol. The expression of poly-His tagged proteins, and the procedure for the highly selective peptide and protein acylations are detailed in this contribution. The versatility of these methods has been demonstrated by the attachment of different functionalities such as fluorophores, biotin, and azides to different proteins and an antibody., (Copyright © 2024. Published by Elsevier Inc.)

Amphiphilically modified kaolinite was produced by the modification of the octahedral surface of kaolinite with vinyltrimethoxysilane for use in the stabilization of Pickering emulsions. The covalent grafting of the hydrolysate of vinyltrimethoxysilane on the kaolinite octahedral surface resulted in kaolinite exhibiting dual-surface affinity. Further, the surface wettability of the modified kaolinite could be tuned by regulating the reaction temperature. Investigations of emulsions stabilized using the modified kaolinite samples indicated that the emulsion stability was significantly higher. In addition, the phenomenon of phase inversion could be controlled based on the wettability of the modified kaolinite. The highest stability of emulsion was observed when the emulsion droplet size was the lowest and the emulsion viscosity was the highest at the phase-inversion point. These findings should lead to the development of methods for preparing amphiphilic surface-active emulsifiers as well as the production of the desired types of emulsions at a given water/oil ratio. [ABSTRACT FROM AUTHOR]

Abstract: Amino‐γ‐lactam (Agl) bridged dipeptides, commonly known as Freidinger lactams, have been shown to constrain peptide backbone topology and stabilize type II′ β‐turns. The utility of these links as peptide constraints has inspired new approaches to their incorporation into complex peptides and peptoids, all of which require harsh reaction conditions or protecting groups that limit their use on unprotected peptides and proteins. Herein, we employ a mild and selective alkylation of selenomethionine in acidic aqueous solution, followed by immobilization of the alkylated peptide on to bulk reverse‐phase C18 silica and base‐induced lactamization in DMSO. The utilization of selenomethionine, which is readily introduced by synthesis or expression, and the mild conditions enable selective backbone engineering in complex peptide and protein systems. [ABSTRACT FROM AUTHOR]

The selective modification of sodium montmorillonite (Na+-Mt) surface with polyionene followed by poly (succinimde-co-aspartate) has been considered. Na+-Mt was allowed to react with well characterized polyionene in two fold excess. The resulting polyionene/Mt (IC) was further modified with poly (succinimide-co-aspartate) through an ion exchange process. The obtained polyaspartate/Mt (IPS) composite was characterized by elemental analysis, X-ray diffraction, FTIR spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and BET surface analyzer. The adsorption efficiency of IPS composite was investigated for the removal of Pb(II) and Cd(II) from aqueous solution under different experimental conditions including initial metal ions concentration, temperature and single and binary mixture systems of metal ions. The experimental data were analyzed by Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models. Langmuir model reveals that the monolayer adsorption capacity of IPS was 92.59 and 67.57 mg/g for Pb(II) and Cd(II), respectively. The modification of parent Na+-Mt enhanced their adsorption capacity by about 87.91 and 29.84% for Pb(II) and Cd(II), respectively, due to inclusion of extra active sites of polyaspartate. The mean sorption energy, E calculated from Dubinin–Radushkevich isotherm were 2.75 and 1.98 kJ/mol for the adsorption of Pb(II) and Cd(II), respectively, indicating physical adsorption process. Also, The thermodynamic parameters were calculated and indicated that the adsorption was spontaneous and exothermic process. The mechanism of cation exchange and complexation of metal ions was suggested. IPS composite has a considerable potential for the removal of heavy metal ions from aqueous solution and wastewater stream. [ABSTRACT FROM AUTHOR]

In this paper, we review the chemical strategies used for the modification of the inner surface of halloysite nanotubes (HNTs). The HNTs are nanotubular materials formed by rolling up the 1:1 aluminosilicate clays, where the composition is similar with kaolin. Owing to many virtues, including the high ratio of length to diameter, large cavity volume, desirable biocompatibility, and low cost, the HNTs have been applied to numerous promising domains. The modification of the outer surface is usually intended to decrease the HNT dispersal in aqueous media. Considering that the selective modification for the inner surface gives excellent prospects for hybrid HNT-based materials, herein, we explore the advances in the selective modification of the inner surface that expanded the applications of the HNTs. [ABSTRACT FROM AUTHOR]

The reaction between the antimalarial drug dihydroartemisinin (DHA) and hemoglobin A (HbA) was investigated in vitro. A fluorescein-tagged artemisinin analog reacted with HbA and fluorescent HbA-drug adducts could be visualized on SDS-PAGE to confirm stable covalent reaction adducts and necessity of the endoperoxide moiety and Fe(II). Mass spectrometric analyses revealed that DHA favourably alkylated protein part rather than heme and the modification site was identified to be at Tyr35 of the beta globin chain. [ABSTRACT FROM AUTHOR]

Two Janus-type catalysts were synthesized by selective modification and further functionalization with metal nanoparticles on one or both beads of snowman-like Janus particles. The catalytic performance of Janus-type catalysts both in homogeneous and interfacial reaction systems was systematically investigated using the reduction of nitro-compound as model reaction. The results showed that Janus-type catalysts have excellent catalytic activity in homogeneous reaction system and they are easy to recycle. Further, the Janus-type catalysts exhibited more efficient catalytic activity at emulsion interface than that of oil-water biphasic interface due to the exposed Au nanoparticles on snowman-like Janus particles offer high accessibility to reactants. [ABSTRACT FROM AUTHOR]

In this work, the exceptional strength-ductility synergy of a dual-phase high entropy alloy (HEA) is achieved by architecting complex microstructures. The HEA rolled at 700 °C shows the yield strength and tensile strength as high as 1580 MPa and 1854 MPa with ductility of ∼18.4%. Different flow stress regions (face-centered cubic (FCC) and body-centered cubic (BCC) phases) divided by complex microstructures lead to strong hetero-deformation-induced strain hardening. The dispersed micro-strain band and the precipitates buffering the dislocation in front of the heterogeneous phase boundary also help to improve the ductility. In addition, utilizing the sensitivity difference between FCC and BCC phases for dislocation accumulation, more dislocations are accumulated in FCC phase to reduce the mechanical incompatibility with BCC phase and fully release the strain hardening ability. The strategy of architecting complex microstructures and selectively modifying phases will be beneficial to the development of high-performance dual-phase alloys. [ABSTRACT FROM AUTHOR]

Inulins are a group of abundant, water-soluble, renewable polysaccharides, which exhibit attractive bioactivities and natural properties. Improvement such as chemical modification of inulin is often performed prior to further utilization. We hereby presented a method to modify inulin at its primary hydroxyls to synthesize amphiphilic aminated inulin via ‘click chemistry’ to facilitate its chemical manipulation. Additionally, its antibacterial property against Staphylococcus aureus ( S. aureus ) was also evaluated and the best inhibitory index against S. aureus was 58% at 1 mg/mL. As the amphiphilic aminated inulin is easy to prepare and exhibits improved bioactivity, this material may represent as an attractive new platform for chemical modifications of inulin. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous silicas with hexagonally arranged pore channels were synthesized in water–ethanol-ammonia solution using cetyltrimethylammonium bromide as template. Directed modification of silica surface with N-[N′-(N′-phenyl)-2-aminophenyl]-3-aminopropyl groups was realized by postsynthetic activation of halogenoalkylsilicas, which have surface uniformly or selectively distributed 3-chloropropyl groups, with 2-aminodiphenylamine in the liquid phase. Chemical composition of silica materials was estimated by IR spectroscopy and chemical analysis of the surface products of reactions. Characteristics of porous structure of MCM-41-type silicas were determined from X-ray and low-temperature nitrogen ad-desorption measurements. Release ability of synthesized silica carriers was established on encapsulation of 4-aminobenzoic acid in pore channels and subsequent delivery at pH=6.86 and pH=1.00. It was found that N-[N′-(N′-phenyl)-2-aminophenyl]-3-aminopropyl groups block pore entrances at neutral pH preventing 4-aminobenzoic acid release. At pH=1.00 repulsion of positively charged surface aromatic amino groups localized near pore orifices provides unhindered liberation of aromatic amino acid from mesoporous channels. [Copyright &y& Elsevier]

Highlights: [•] Selective ablation of SAM mPEG-sil via localized Joule heating in vacuum was optimized and performed for silicon nanobelt field-effect transistor (SNFET). [•] Unlike resistive device, the ablated region is located at the p− regions and shifts to the drain side of the SNFET as a result of impact ionization. [•] Fluorescence image of selective modification presents consistent results with the LFM images. [•] The sensing response rate for selectively modified SNFET is twice as fast as the non-selectively modified one. [ABSTRACT FROM AUTHOR]

Abstract: Inulin, a kind of abundant, water-soluble, renewable polysaccharide, is mainly extracted from such low-requirement crops as Jerusalem artichoke, chicory, and yacon. The objective of this study was to modify inulin at its primary hydroxyls to give 6-amino-6-deoxyinulin, allowing for the facile chemical manipulation of inulin to encourage the employment of this currently underutilized biodegradable and environmentally benign resource. Additionally, its antifungal properties against two strains of phytopathogens, Cladosporium cucumerinum (Ell.) et Arthur and Fusarium oxysporum sp. Cucumis sativus L., were also evaluated by hypha measurement in vitro and the inhibitory indices against these two fungi were 60.1% and 53.3% at 1000μg/mL, respectively. Because 6-amino-6-deoxyinulin is easy to prepare and exhibits improved potential activities, this material may represent an attractive new platform for chemical modifications of inulin. [Copyright &y& Elsevier]

Abstract: The selective modification of cyclodextrins remains a real challenge to obtain well-defined structures. The targeted cycloheptakis-(1→4)-2,6-di-O-hydroxypropyl-3-O-methyl-α-d-glucopyranosyl [per(2,6-di-O-hydroxypropyl-3-O-methyl)-β-CD] was obtained by a three-step procedure. The selective allylation of the hydroxyl functions at the positions 2 and 6 was used as a first step. This reaction was revisited then enlarged to α and γ-CDs to determine new conditions for a one-step synthesis in high yield. The per(2,6-di-O-allyl)-β-CD derivative was then reacted with iodomethane to provide per(2,6-di-O-allyl-3-O-methyl)-β-CD. Oxidative hydroboration of the allyl functions was then carried out in order to obtain a new CD derivative with seven primary hydroxyl functions on each side of the truncated cone, having a similar reactivity. [Copyright &y& Elsevier]

Abstract: The textural structure and the surface property of activated carbon were selectively modified by KMnO4 oxidation. The activated carbon treated by KMnO4 oxidation in an acidic solution showed greatly enhanced H2O2 production by hydroxylamine oxidation due to the creation of more surface quinoid species, and the yield of hydrogen peroxide approached 78% (0.66wt.%). Structure and surface analyses revealed that KMnO4 oxidation in the acidic solution produced more phenolic but less carboxylic groups on the activated carbon, confirming the crucial role of the quinoid groups. It was further proposed that the quinoid groups serving as electron acceptors and redox mediators involved in the formation of H2O2 through a redox cycle. [Copyright &y& Elsevier]

Natural glycoproteins are mixtures of multiple glycoforms possessing identical peptide backbones, but differing in composition of glycan parts. This microheterogeneity presents a serious challenge in pharmaceutical applications of glycoproteins, where well-characterized and reproducible structural characteristics are required. Due to the growing importance of biopharmaceutical glycoconjugates, a wide variety of practical approaches to the preparation of glycosylated proteins and oligopeptides have been developed in recent years, with emphasis on strategies for selective glycosylation. This review presents a concise summary of concepts and synthetic approaches currently employed in glycoprotein chemistry. [Copyright &y& Elsevier]

Mono-2-O-benzylated eicosa-O-methylcyclomaltoheptaose (-β-cyclodextrin) was prepared in one pot from cyclomaltoheptaose (β-cyclodextrin) in 33% isolated yield and quantitatively converted to mono-2-OH-free eicosa-O-methylcyclomaltoheptaose, which is the key compound for further modification. Transformation of this 2-OH group successfully gave several mono-2-O-modified eicosa-O-methylcyclomaltoheptaoses such as the acetate, the N,N-dimethylcarbamate, the N-n-butylcarbamate, the methanesulfonate, and the S-methyldithiocarbonate. [Copyright &y& Elsevier]

• Ag NPs were successfully loaded in the lumen of HNTs. • The MEF effect of the nanoprobe provided ultra-sensitive detection of TC. • The presence of Ag in the nanoprobe can also enhance the degradation of TC. The ultrasensitive detection and efficient degradation of tetracycline (TC) residues are important for improving food safety and protecting human health. In this paper, a smart silver-enhanced fluorescence platform for the ultrasensitive detection of TC was constructed via a simple and selective modification of the interior and external tubes of natural halloysite nanotubes. The thick pipe wall of this platform provides a natural defense and promotes metal-enhanced fluorescence effects, which subsequently accelerates the detection of TC. Moreover, the nanoplatform of the modified Ag nanoparticles can induce the separation of electrons and holes, thereby enhancing photocatalytic activity in TC degradation. This platform provides new opportunities for studying natural halloysite nanotubes and for simultaneously detecting and photodegrading other deleterious substances. [ABSTRACT FROM AUTHOR]

The current contrast agents utilized in ultrasound (US) imaging are based on microbubbles which suffer from a short lifetime in systemic circulation. The present study introduces a new type of contrast agent for US imaging based on bioresorbable Janus nanoparticles (NPs) that are able to generate microbubbles in situ under US radiation for extended time. The Janus NPs are based on porous silicon (PSi) that was modified via a nanostopper technique. The technique was exploited to prepare PSi NPs which had hydrophobic pore walls (inner face), while the external surfaces of the NPs (outer face) were hydrophilic. As a consequence, when dispersed in an aqueous solution, the Janus NPs contained a substantial amount of air trapped in their nanopores. The specific experimental setup was developed to prove that these nano air seeds were indeed acting as nuclei for microbubble growth during US radiation. Using the setup, the cavitation thresholds of the Janus NPs were compared to their completely hydrophilic counterparts by detecting the subharmonic signals from the microbubbles. These experiments and the numerical simulations of the bubble dynamics demonstrated that the Janus NPs generated microbubbles with a radii of 1.1 μm. Furthermore, the microbubbles generated by the NPs were detected with a conventional medical ultrasound imaging device. Long systemic circulation time was ensured by grafting the NPs with two different PEG polymers, which did not affect adversely the microbubble generation. The present findings represent an important landmark in the development of ultrasound contrast agents which possess the properties for both diagnostics and therapy.

A novel fluorescence probe based on modified halloysite nanotubes (HNTs) by using 1-pyrenylboronic acid selectively grafted onto the inner surface of lumen was successfully achieved. The solid-state nuclear magnetic resonance ((13)C and (11)B), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) confirmed that the boronic acid group only binds to alumina at the tube lumen and does not bind the tube's outer siloxane surface. The modified HNTs (HNTs-PY) inherit the spectroscopic properties relating to the pyrene units. Interestingly, the established Al-O-B linkage gives the H2O2-sensitivity to pyrene grafted tubes. HNTs-PY exhibits a highly specific "turn-off" response for hyperoxide over other reactive oxygen species (ROS) and oxidative ions owing to their chemoselective boronate-to-phenol switch. The "turn-off" response can even be tracked when the additional amount of H2O2 was limited to 1 × 10(-6) mol. Thus, the selective modification method under mild conditions for the design of novel organic-inorganic hybrid fluorescence probe may open up a broader application as well as for identification and diagnosis.