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Shikonin (Shik), a natural pigment, has received growing interest in various biomedical fields due to its anti-inflammatory, antitumor, antimicrobial, and antioxidant ability. However, some inherent characteristics of Shik, such as its virulence, low bioavailability, and poor solubility, have limited its biomedical applicability. Here, we reported a facile synthetic method to produce the Shik-iron (III) nanoparticles (Shik-Fe NPs), which could overcome these limitations of Shik. The synthesized Shik-Fe NPs possessed a uniform size range of 110 ± 10 nm, negative surface charges, good water dispersity, and high safety. Iron distributed uniformly inside Shik-Fe NPs, and iron constituted 20% of total mass in PEGylated Shik-Fe NPs. When interacting with activated macrophages, Shik-Fe NPs significantly reduced the level of cellular inflammatory factors, for example, iNOS, IL-1β, and TNF-α. Furthermore, the Shik-Fe NPs demonstrated synergistic anti-inflammation and anti-bacterial properties in vivo, since they could release Fe 3+ and Shik to eradicate bacteria ( Staphylococcus aureus and P. aeruginosa were used as model microbes here) during wound infections and provide full recovery for scald wounds. Collectively, the study established a dual-functional Shik-derived nanoplatform, which could be useful for the treatment of various inflammation-involved diseases.

A simple, environmentally friendly and cost-effective nonsurfactant template method was used to synthesize tannic-acid-templated mesoporous silica nanoparticles (TMSNs), and then dopamine functionalized TMSNs (Dop-TMSNs) which was synthesized by a facile and biomimetic coating strategy, was developed as a new sorbent for the removal of Cu 2+ from aqueous solution. The Dop-TMSNs were thoroughly characterized by SEM, TEM, BET, FT-IR and TGA, and the effects of contact time, initial pH, K + and Na + concentrations, co-existing polyvalent metal ions and adsorption-desorption cycle times on the sorption capacity of Dop-TMSNs were studied. It was demonstrated that the maximum adsorption capacity of Cu 2+ by Dop-TMSNs was 58.7 mg/g at pH 5.5, and the sorption reached equilibrium within 180 min. Moreover, the K + and Na + concentrations had a very slight influence on the sorption process and the adsorption capacity of the Dop-TMSNs still remained 89.2% after recycling for four times. All the results indicated that the Dop-TMSNs could be utilized as an excellent sorbent for the sequestration of Cu 2+ .

Inspired by biomineralization, design and preparation of biomimetic organic-inorganic composites have become a hot issue and a research frontier in many areas, including enzyme engineering. In this research, a unique and facile method for fabricating organic-inorganic hybrid beads is proposed. Modified alginate with a dual function of gelation and mineralization was synthesized for fabrication of hybrid carriers for enzyme immobilization. With the aid of EDC/NHS conjugation chemistry, the amine groups from diethylene triamine were grafted onto alginate in a controllable way. The resultant aminated alginate served manifold functions: forming a hydrogel via Ca(2+)-cross-linking, inducing the biomimetic silicification and manipulating the distribution of silica nanoparticles. Owing to the compact polymer network structure and the homogeneous silica nanoparticle dispersion, the as-prepared NH2-alginate/silica hybrid beads displayed superior swelling resistance and mechanical stability to pure alginate beads. The hybrid beads were subsequently utilized for encapsulation of yeast alcohol dehydrogenase (YADH). It was found that the thermal stability, pH tolerance and storage stability of the immobilized enzyme were all improved without significantly lowering the catalytic activity.

Protamine, a kind of cationic protein extracted from sperm nuclei, was employed for the first time in vitro to induce the formation of a titania/protamine nanoparticle composite from a water-stable titanium precursor, titanium(IV) bis(ammonium lactato) dihydroxide (Ti-BALDH). The resulting titania/protamine nanoparticle composite was extensively characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The titania/protamine nanoparticle composite was of amorphous structure, and exhibited a different morphology from those prepared by an alkali-catalyzed approach. The catalyzing and templating function of protamine involved in the synthesis of the nanoparticle composite is discussed, and a mechanism tentatively proposed. In addition, the effects of pH and temperature on the amount and size of as-prepared titania/protamine nanoparticle composite were systematically investigated.

Main observation and conclusion: Aqueous heterogeneous catalysis is a green, sustainable catalytic process that attracts increasing attention, but it often suffers from poor mass transfer, substrate adsorption and catalyst dispersion. Herein, we synthesized a type of amphiphilic core‐shell catalysts with a hydrophilic polydopamine (PDA) shell and a hydrophobic dendritic organosilica nanoparticle (DON) core for heterogeneous catalysis in water. The hydrophilic shell allowed the catalyst dispersing well in water, and the hydrophobic core facilitated the absorption of organic reactants. The hierarchical core‐shell structure facilitated rational arrangement of the location of catalytic species to match the reaction sequence. The obtained metal, enzyme and metal‐enzyme amphiphilic catalysts demonstrated improved stability, selectivity and activity in aqueous reactions, including Pd‐catalyzed cross‐couplings (Suzuki, Liebeskind‐Srogl, Heck and Sonogashira), enzymatic enantioselective reduction, chemoenzymatic cascade synthesis of chiral compounds and chemoenzymatic cascade degradation of organophosphates. The amphiphilic catalysts could be easily in situ recovered, and their high catalytic performance was sustained for five cycles. [ABSTRACT FROM AUTHOR]

Chemoenzymatic catalysts with hydrophobic nanopores were fabricated by co-immobilizing metal nanoparticles and enzymes into the dendritic organosilica nanoparticles. They demonstrated highly improved catalytic performance in chemoenzymatic asymmetric synthesis of chiral amines and alcohols. The hydrophobic microenvironment proved to be critical to enhanced stability, activity and cascade efficiency. [ABSTRACT FROM AUTHOR]

Simultaneous size control and surface functionalization of inorganic nanoparticles (NPs) are often desired for their efficient applications in (bio)catalysis, drug and/or DNA delivery, and photonics, etc. In this study, a novel strategy 'bioadhesion-assisted bio-inspired mineralization (BABM)' was put forward to prepare titania nanoparticles (TiNPs) with tunable particle size and multiple surface functionality. Specifically, the initial formation and subsequent growth of TiNPs were enabled by arginine via bio-inspired mineralization, while the mineralization process was terminated through the addition of the pre-polymerized dopa (oligodopa). By adjusting the addition time of oligodopa, the size of TiNPs could be facilely tailored from ca. 30-350 nm; meanwhile, the surface of TiNPs could be functionalized by oligodopa through metal-catechol coordination interaction (a typical bioadhesion phenomenon). In other words, oligodopa coating could not only exquisitely control the size of TiNPs, but also render TiNPs surface multifunctional groups for secondary treatment such as conjugating proteins through amine-catechol adduct formation. Hopefully, this BABM approach will construct a versatile platform for green and facile synthesis of inorganic NPs, in particular transition metal oxide NPs. [ABSTRACT FROM AUTHOR]

Abstract: This study demonstrates a novel biomimetic approach for the entrapment of yeast alcohol dehydrogenase (YADH) within titania nanoparticles to improve its stability. Protamine was as the template and catalyst for the condensation of titanium (IV) bis(ammonium lactato) dihydroxide (Ti-BALDH) into titania nanoparticles in which YADH was trapped. The as-prepared titania/protamine/YADH composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The mechanism of YADH encapsulation was tentatively proposed from a series of experimental results. The preliminary investigation showed that encapsulated YADH could retain most of its initial activity. Compared to free YADH, encapsulated YADH exhibited significantly improved thermal, pH and recycling stability. After 5 weeks storage, no substantial loss of catalytic activity for encapsulated YADH was observed. [Copyright &y& Elsevier]

A nano-form composite of MXenes (Ti3C2Tx, Tx = -O, -OH, -F) was synthesized through depositing bismuth-nanoparticle (BiNPs) onto Ti3C2Tx sheets. Because of the preventive effect of the two-dimensional layered structure of Ti3C2Tx, the nanoparticles of Bi were uniform and well attached on the Ti3C2Tx. The obtained BiNPs/Ti3C2Tx nano-composite was applied for sensors construction of electrochemical detecting of Pb2+ and Cd2+ heavy metal ions. The produced BiNPs@Ti3C2Tx-based sensor showed high effective surface area and excellent conductivity. Also, the BiNPs were efficient for anodic-stripping voltammetric to detect heavy metal ions. After conditions optimization, the BiNPs@Ti3C2Tx nano-sensor could detect Pb2+ and Cd2+ simultaneously and the detection limits were 10.8 nM for Pb2+ and 12.4 nM for Cd2+. The BiNPs@Ti3C2Tx was promising for detecting heavy metal ions due to their high surface area, fast electron-transfer ability, environmental friendliness, and facial preparation. [ABSTRACT FROM AUTHOR]

Manganese is a contaminant of concern for many drinking water utilities, and future regulation may be pending. An analysis of soluble manganese (Mn(II)) oxidation by ferrate (Fe(VI)) was executed at the bench-scale, in a laboratory matrix, both with and without the presence of natural organic matter (NOM) and at two different pH values, 6.2 and 7.5. In the matrix without NOM, the oxidation of Mn(II) by Fe(VI) followed a stoichiometry of 2 mol Fe(VI) to 3 mol Mn(II). The presence of NOM did not significantly affect the stoichiometry of the oxidation reaction, indicating relative selectivity of Fe(VI) for Mn(II). The size distribution of resulting particles included significant amounts of nanoparticles. Resulting manganese oxide particles were confirmed to be MnO 2 via X-ray photoelectron spectroscopy. The rate of the Mn(II) oxidation reaction was fast relative to typical time scales in drinking water treatment, with an estimated second order rate constant of approximately 1 × 10 4 M −1 s −1 at pH 9.2 and > 9 × 10 4 M −1 s −1 at pH 6.2. In general, ferrate is a potential option for Mn(II) oxidation in water treatment. [ABSTRACT FROM AUTHOR]

The as-prepared OpdA@Co/C@SiO 2 @Ni/C, a novel yolk − shell structured integrated nanocatalyst, has achieved a one-pot chemoenzymatic cascade degradation of organophosphates (OPs) to p -aminophenol (PAP). • The yolk-shell structured Co/C@SiO 2 @Ni/C showed excellent catalytic performance. • Co/C@SiO 2 @Ni/C exhibited good selectivity and adsorbability for His-rich proteins. • The integrated nanocatalyst can realize cascade degradation of organophosphates. • The integrated nanocatalyst provides a robust strategy for environmental remediation. The synthesis or decomposition of complex substances through the combination of metals and enzymes is desirable but still a huge challenge. A kind of yolk-shell structured Co/C@SiO 2 @Ni/C nanocomposites were prepared by the polyhedral ZIF-67@SiO 2 composite as a precursor through the extended stöber method and subsequent carbonization treatment. The SiO 2 as an intermediate protective layer stabilized the morphology and structure of the carbonized products. The metallic nickel nanoparticles were uniformly distributed on the surface of Co/C@SiO 2 @Ni/C for highly specific absorption of His-tagged organophosphohydrolase (OpdA) from cell lysates via affinity, and therefore an integrated nanocatalyst (INC) named OpdA@Co/C@SiO 2 @Ni/C was successfully prepared. The prepared INC was applied to achieve a one-pot chemoenzymatic cascade degradation of organophosphates (OPs) to p -aminophenol (PAP) within 30 min. In addition, the INC proved to be a simple and high-sensitivity nanocatalyst for the detection of methyl-parathion with a low limit of detection (0.30 μM). The INC exhibited improved pH stability, thermal stability, SDS resistance, and storage stability compared to that of free enzymes. When OpdA@Co/C@SiO 2 @Ni/C was reused for 7 cycles, the cascade degradation efficiency of methyl-parathion could retain more than 60 %. This study provides a strategy for constructing a multifunctional nanocatalyst, and further demonstrated its potential in biocatalysis, accurate detection of OPs and remediation of environmental pollution. [ABSTRACT FROM AUTHOR]

Urchin-like 3D Mn 3 O 4 -sensor was synthesized using a gentle method and used to detect the concentration of GSH in human serum samples. • A novel GSH biosensor based on urchin-like Mn 3 O 4 nanoparticles was fabricated. • The GSH biosensor exhibited perfect stability, sensitivity and selectivity. • The GSH biosensor showed good linear relationship, low LOD and rapid response. • This study extended the applications of GSH biosensor in catalysis and chem/biosensors. Urchin-like trimanganese tetroxide (Mn 3 O 4) particles were synthesized through a simple and gentle method, and characterized by XRD, XPS, FTIR, SEM, TEM, and UV–vis absorption. The intrinsic enzyme-like activity of urchin-like Mn 3 O 4 particles was evaluated by 3, 3′, 5, 5′-tetramethylbenzidine (TMB) in the absence of H 2 O 2. The optimization of experiment conditions of urchin-like Mn 3 O 4 particles on the oxidase-like activity was further investigated. It was exhibited that urchin-like Mn 3 O 4 particles were best-performing with a highly oxidase-like catalytic activity in the model reaction. Due to the selective inhibition of glutathione (GSH) on the high oxidase-like activity of urchin-like Mn 3 O 4 particles, a selective and sensitive colorimetric assay for GSH had been established. The method exhibited linear relationship over the GSH concentration range from 0.1 μM to 30 μM, with a low detection limit of 20.0 nM and a rapid response of less than 3 min. Based on high specificity of GSH inhibition, urchin-like Mn 3 O 4 particles could be used to detect GSH concentration in human serum samples. [ABSTRACT FROM AUTHOR]