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The rational design and controlled synthesis of nanoarchitectures is an important strategy for understanding structure–activity relationships.

Herein, a yeast cell, with neither photosynthetic properties nor hydrogen production abilities, is endowed with efficient solar-to-chemical hydrogen production via in situ biosynthesized intracellular nanodots triggering enzyme-catalyzed reactions.

Here, we report a size-responsive and high-active hydrogenation living cell catalytic system (LCCS). The “gating” effect of the channels in the cell membrane endows the LCCSs with excellent size-responsivity for catalytic substrates.

Aerobic oxidation of benzylamine to imine by cooperative photocatalysis of DHNS–Nb2O5 and TEMPO is viable.

TEMPO+PF6− substantially accelerates the blue light-initiated aerobic oxidation of benzyl amines into imines over TiO2 microspheres.

Nb2O5 is a colourless metal oxide that is very promising in areas such as energy storage and optical glasses. These applications depend on the superior redox properties of Nb2O5 compared to those of other metal oxides, which in turn endow it with great potential in semiconductor photocatalysis. Herein, a hierarchical Nb2O5 was synthesized by the L-arginine-assisted hydrothermal method. Thereafter, visible light photocatalysis was bridged over hierarchical Nb2O5 with a common organic dye, namely alizarin red S (ARS), significantly renovating Nb2O5-based photocatalysis from ultraviolet (UV) into the green light region. The surface of hierarchical Nb2O5 was chemically modified with ARS to harvest 520 nm green light and facilitate the oxidation of organic sulfides with aerial O2. The O-atom transfer from O2 into sulfoxides with very high selectivity occurs via an intermediate of superoxide radical anions (O2˙−). Importantly, the electron transfer from activated ARS to sulfides is mediated by an electron transfer mediator, namely (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), to deter the attack of quenched ARS by reactive oxygen species (ROS). This study represents the first foray of dye-semiconductor assemblies based on a semiconductor other than TiO2 for the selective aerobic oxidation, affirming the generality of cooperative photocatalysis and implying the great potential of hierarchical Nb2O5 in platforming the visible-light-induced selective transformation of organic molecules.

Nanoparticles are produced by chemical methods which are usually environmentally hazardous because of the use of various perilous chemicals and harsh reaction conditions. Bio-mediated synthesis using microbes has been proved to be a promising substitute for traditional methods to synthesize nanoparticles. Herein, based on the principles of biomimetic mineralization, a bio-mediated strategy was proposed to synthesize biocompatible barium carbonate nanoparticles (nBaCO3) in living yeast cells according to the intracellular biochemical reactions using tactfully the interaction of endogenous CO32− and exogenous Ba2+ under normal growth conditions of the yeast cells. The intracellular nBaCO3 are well-dispersed and the diameter of the nanoparticles is successfully controlled at about 5 nm under mild conditions. The bio-mediated strategy to obtain nanomaterials can be universally applied to biosynthesize other kinds of components with good biocompatibility. This biosynthesis route for barium carbonate nanoparticles mediated by the cells not only presents a green and facile design to synthesize well-tailored nanomaterials using a biomineralization-inspired strategy but may also lead to new insights for nanotechnology.

Inspired by biomineralization, the first synthesis of size-tunable calcium carbonates from nanoparticles (YC-CaCO3 NPs) to nano/microspheres (YC-CaCO3 N/MSs) with a porous structure was accomplished using a facile method under the mediation of the secretion from yeast cells (YCs). The biomolecules derived from the secretion of YCs were used as conditioning and stabilizing agents to control the biosynthesis of the YC-CaCO3 materials. The morphology and crystal forms of YC-CaCO3 materials can be affected by the biomolecules from the secretion of YCs. With increasing concentrations of biomolecules, the morphologies of the obtained CaCO3 materials changed from nanoparticles to nano/microspheres with a porous structure, while the crystal forms transformed from amorphous to calcite. Functional investigations showed that YC-CaCO3 NSs with a porous structure effectively acted as anticancer drug carriers with accurate and selective drug release in tumor tissue, which suggests that they have great potential to function as a therapeutic delivery system. These application features are mainly attributed to the satisfactory biocompatibility and biodegradability, high drug-loading capacity, and pH-dependent sustained drug release performance of the porous YC-CaCO3 NSs. The biomimetic synthesis strategy of YC-CaCO3 materials mediated by YC secretion not only helps to shed light on the biomineralization mechanism in organisms, but may also lead to a new means of biosynthesizing organic–inorganic nanocomposites.

1D titanate (H2Ti3O7) nanotubes were prepared by a hydrothermal treatment of TiO2 under 10 M NaOH and ensuing acid exchange process. Here, it is discovered that H2Ti3O7 nanotubes can facilitate the merger of organic photocatalysis and TEMPO catalysis. Confined within H2Ti3O7 nanotubes, the organic photocatalyst erythrosin B (ErB) could drive the highly selective aerobic oxidation of sulfides under irradiation of green light-emitting diodes (LEDs), when 0.5 mol% of TEMPO was added as a co-catalyst. The turnover number (TON) for photocatalytic selective aerobic oxidation of thioanisole in terms of ErB is 2450, which is hitherto the best reported TON. Apart from confining the successful merger of ErB photocatalysis and TEMPO catalysis, H2Ti3O7 nanotubes not only activate O2 to generate superoxide anion radical (O2˙−), but also ensure high selectivity of sulfoxides with their abundant surface hydroxyl groups. This work represents a crucial step forward in selective oxidation reactions by materials design of dye-semiconductor assembly photocatalysts.

Selective conversion of carbon dioxide (CO2) to a reusable form of carbon via electrochemical reduction has attracted intensive interest for the storage of renewable energy. However, the achievement of efficient bulk monolithic electrocatalysts still remains a challenge. Herein, a facile oxidative etching of the Au20Cu80 alloy was developed for the synthesis of a monolithic nanoporous core–shell structured AuCu3@Au electrode, which showed a faradaic efficiency (FE) of 97.27% with a partial current density of 5.3 mA cm−2 at −0.6 V vs. RHE for the production of CO. The FE value is about 1.45 times higher than that over the Au nanocatalyst. Unlike single nanoporous Au, AuCu3@Au maintained an excellent performance in a broad potential window. Furthermore, a 23 cm long nanoporous AuCu3@Au bulk electrode with good ductility was prepared, over which the active current reached up to 37.2 mA with a current density of 10.78 mA cm−2 at −0.7 V vs. RHE, pushing the reduction of CO2 to industrialization. The unsaturated coordination environment with a coordination number of 8.2 over the shell gold and curved interface determined this high electrocatalytic performance. Density functional theory calculations suggested that the double-dentate adsorption structure in the AuCu3@Au catalyst effectively improves the stability of the *COOH intermediate. The density of states indicates that the introduction of Cu causes the d-band-centre of AuCu3@Au to move toward the Fermi level, directly bonding with *COOH. Therefore, the adsorption of *COOH on the surface of the AuCu3@Au catalyst is strengthened, facilitating the formation of CO. This work opens an avenue to achieve self-supported porous electrodes for various useful catalytic conversions.

A [4 + 2] annulation involving cascade Knoevenagel, aza-Wittig and dehydrofluorination reactions is developed for the synthesis of substituted quinolin-4-ols including analogs bearing CF2H, CF3, and C2F5 groups. This simple and highly efficient method is also applicable for the synthesis of substituted quinolines. A number of reported biologically active compounds can be readily prepared by this one-pot synthesis. Green chemistry metrics analysis of the new reaction processes provided favorable results.

Sulfidation of silver nanoparticles (Ag-NPs) readily occurs in both urban sewage systems and sulfur-rich natural environments with formation of silver sulfide nanoparticles (Ag2S-NPs). It is essential to understand the transformation and fate of Ag2S-NPs in order to fully evaluate environmental impact of Ag-NPs. The review focuses on the formation and transformation of Ag2S-NPs from both thermodynamic and kinetic perspectives, particularly (i) the formation mechanism of Ag2S in various environmental scenarios, (ii) redox transformation of Ag2S caused by oxidation of S(−II) and (iii) effects of environmental matrices on the formation and transformation processes. In most cases, sulfidation of Ag-NPs causes a dramatic decrease in their toxicity due to the extremely low solubility of Ag2S, potentially restraining their short-term environmental impact. However, the transformation of Ag2S-NPs with potential release of Ag+ and in situ formation of Ag0 and Ag0/Ag2S-NPs hetero-nanostructures may possibly increase the toxicity. Mechanistically-based kinetic modeling has been proposed here to quantitatively describe the rate and extent of the transformation of Ag2S-NPs, with such models of value, at least, in validating proposed transformation mechanisms of Ag2S-NPs and, at best, in predicting their transformation behaviors under realistic environmental conditions.

A new synthetic method for diastereoselective synthesis of tetrahydro-pyrrolo[1,2-d][1,4]benzodiazepines and tetrahydro-pyrrolo[1,2-d][1,4]diazepinones is developed which involves 1,3-dipolar cycloaddition, N-alkylation or N-acylation and Staudinger/aza-Wittig reactions. This one-pot and three-step synthesis of four components gave two different heterocyclic scaffolds. Green chemistry metrics analysis of the reaction process provided favorable results.

Hierarchical ellipsoid-shaped TiO2 porous nanostructures with a high specific surface area and abundant pores are fabricated by the hierarchical assembly of TiO2 nanoparticles via a simple one-pot hydrothermal process. The as-synthesized ellipsoid-shaped TiO2 exhibits significantly enhanced photocatalytic activity for MB degradation compared to P25 under ultraviolet light and sunlight irradiation, respectively.

High sequence homology among miRNA members challenges miRNA analysis. In this paper, we developed a simple and highly selective method based on a novel G-triplex molecular beacon (MBG3) and duplex-specific nuclease signal amplification (DSNSA) for miRNA detection. Herein, this MBG3 is a label-free molecular beacon with a special G-triplex probe. The excellent controllablity of the G-triplex probe allowed our MBG3 to have a short stem, which protected it from DSN digestion. Therefore, DSN cleavage induced false positive signals in most DSN signal amplification strategies have been minimised efficiently without special modifications. Importantly, the improved recognition ability of MBG3, together with the sensitive substrate selectivity of DSN, makes our novel method suitable for miRNA detection with high selectivity. The signal response of similar miRNA sequences with one-base difference has been reduced from 37% to 8% compared to the traditional linear ssDNA probe-DSN-based method.

Multicomponent reactions (MCRs) involving a minimum of three reactants or reaction centers are conducted in one pot and with a single operational step. This synthetic method has a good pot, atom and step economy in the preparation of diverse and complex molecular scaffolds. Consecutive MCRs, also known as sequential or multiple MCRs, by combining two or more MCRs, exhibit even higher synthetic efficiency, product structural diversity, and molecular complexity. This review article highlights the Ugi, Groebke-Blackburn-Bienaymé, Biginelli, Huisgen, Petasis, Gewald, and Asinger reaction-initiated consecutive MCRs.

A unique mineralized cell-based functional platform with biogenic intracellular hydroxyapatite nanoscaffolds (nHAP@yeasts) has been intelligently constructed using a biomimetic mineralization approach. Such a platform not only preserves the nature and functions of cells but also possesses intracellular nanoscaffolds, which endow the mineralized cells with novel functions in biological and nanotechnological applications. Benefiting from their unique organism shell and inorganic core, the nHAP@yeasts are biocompatible and have a large loading capacity for drugs. Such anaerobic microorganisms could be beneficial as drug carriers for the effective delivery and release of loaded drugs in tumors because they prefer to locate and grow in reduced oxygen surroundings. A functional investigation indicated that the nHAP@yeasts, functionalized with folic acid (nHAP@yeasts-FA) as cell-based carriers, showed dual responsive release profiles based on the FA dependency of tumors and the pH-sensitivity of the HAP nanoparticles, and they significantly inhibited tumor growth while displaying low toxicity. This study for the first time provides a bio-friendly strategy to biosynthesize a mineralized cell-based functional platform with biogenic intracellular nanominerals (carbonate, sulfides, selenides, metals, etc.) for biological and nanotechnological application.

A simple and bio-inspired strategy is reported for the first time to fabricate sea urchin-shaped hollow CaCO3 nanospheres (HCNSs) with a hierarchically porous hollow structure under the mediation of soybean trypsin inhibitor (STI). The hierarchically porous structure makes the HCNSs exhibit not only a high loading capacity but also a prolonged release time by the stepwise release of DOX from the mesoporous structure. Through in vitro experiments, we found that the entry of the hierarchical HCNSs into HeLa cells possibly involved an extracellular decomposition, due to the extracellular and intracellular acid microenvironment of solid tumor tissues, and a subsequent endocytosis pathway. In view of the pH-sensitive property as well as the hierarchically porous hollow structure, as well as the excellent biocompatibility and biodegradability of the as-prepared HCNSs, the hierarchically porous hollow CaCO3 could be a promising candidate as an anticancer drug carrier, and would be of great importance in practical and clinical use.

Seed-mediated synthesis of gold nanorods (AuNRs) has been widely used for diverse applications in the past decade. In this work, this synthetic process is demonstrated for multicolor biosensing for the first time. Our investigation reveals that ascorbic acid acts as a key factor to mediate the growth of AuNRs. This phenomenon is incorporated into the alkaline phosphatase (ALP)-enzyme-linked immunosorbent assay (ELISA) system based on the fact that ALP can catalyze the conversion of ascorbic acid-phosphate into ascorbic acid with high efficiency. This allows us to develop a multicolor ELISA approach for sensitive detection of disease biomarkers with the naked eye. We show the proof-of-concept multicolor ELISA for the detection of prostate-specific antigen (PSA) in human serum. The results show that different colors are presented in response to different concentrations of PSA, and a detection limit of 3 × 10(-15) g mL(-1) in human serum was achieved. The proposed multicolor ELISA could be a good supplement to conventional ELISA for POC diagnostics.

The development of multi-shelled hollow carbonate nanospheres (MHCN) for biomedical applications is challenging, and has not been reported. In this study, a facile approach is firstly reported to synthesize hierarchically porous MHCN with controllable shell numbers using a novel strategy called layer-by-layer thermal decomposition of organic acid salts and templates. The choice of organic acid salts as the reactants is innovative and crucial. The shell numbers of porous MHCN can be easily controlled and tuned through adjusting the adsorption temperature of organic acid salts and/or the adsorption ability of the template. The synthetic method can not only open a window to prepare the multi-shelled carbonates but also provide a new strategy to synthesise other multi-shelled inorganic salts. Notably, the hierarchically porous multi-shelled hollow structures empower the carbonates with not only a large specific surface area but also good porosity and permeability, showing great potential for future applications. Herein, our in vitro/vivo evaluations show that CaCO3 MHCN possess a high drug loading capacity and a sustained-release drug profile. It is highly expected that this novel synthetic strategy for MHCN and novel MHCN platform have the potential for biomedical applications in the near future.

The effectiveness of using ligand-assisted strategies to improve the performance of palladium-doped nanoscale zero-valent iron particles (Pd-nZVI) towards contaminant removal has been investigated previously, however, little attention has been given to either the thermodynamics and kinetics of the Pd-nZVI depassivation process or the effect of the presence of co-existent cations. Results of laboratory investigations using EDTA as the ligand of choice indicate that the presence of Ca(II) and Mg(II) ions can significantly improve the ligand-promoted dechlorination efficiency of polychlorinated biphenyls (PCB) with the effect of divalent cations on PCB removal being more significant at higher concentrations of EDTA. The improvement in particle reactivity in the presence of Ca(II) and Mg(II) could be attributed to moderate elimination of outer Fe oxide layers induced by the relatively slow release of free EDTA from Ca and Mg–EDTA complexes. The slow release of free EDTA prevented excessive initial loss of Fe oxide surface sites required for PCB sequestration and ensured that sufficient EDTA remained available for the later-time removal of Fe oxide layers that were continuously formed as Fe0 was oxidized. A mechanistically-based kinetic model for the ligand-promoted dissolution of Pd-nZVI has been developed with this model enabling quantitative understanding of the relatively complex interplay among Ca(II) and Mg(II) ions, EDTA and passivating Fe oxide layers during the contaminant degradation process.

Hierarchically structured m-BiVO4 crystals with twin-ball-like, cauliflower-like, pinwheel-like, columnar and spherical morphologies were synthesized by a facile one-pot method in the presence of soluble starch. The physicochemical properties of the material were characterized by means of XRD, SEM, HRTEM/SAED, UV-vis absorption and N2 adsorption techniques. The oriented aggregation mechanism may rationally explain the formation of the hierarchical structure. The assistance of the starch and the pH value of the precursor solution play pivotal roles in the formation of the hierarchical structures with different morphologies because the existing forms of bismuth and starch vary with the pH value of the precursor solution. The photocatalytic activities of the as-prepared BiVO4 samples were evaluated for the photodegradation of Rhodamine B (RhB) in aqueous solution under simulated sunlight irradiation. The highest photocatalytic activity of BiVO4 obtained at pH = 4 may result from several factors, such as the moderate BET surface area, the highest crystallinity, the lowest bandgap and the most exposed (040) face.

In this study, three types of hierarchical ZnO porous hollow spheres consisting of ZnO nanoparticles with controllable shell numbers were synthesized through different temperature gradient processes using a simplified hard template method. Compared with the traditional hard template method, we facilitated the experiment by the fabrication of zinc precursor-carbon microsphere composites during the formation of carbon microspheres. The shell numbers of the spheres could be controlled by varying the temperature gradient rate during the calcination procedure. Importantly, a different formation mechanism is proposed in this experiment. That is, the synthesis of hierarchical multi-shelled porous hollow spheres might be based on not only the inside-out Ostwald ripening process but also on an unusual temperature gradient crystallization mechanism. Further investigation also revealed that the samples exhibited a varied photocatalysis performance with the efficiency decreasing from the hierarchical triple-shelled porous hollow spheres to the single-shelled spheres progressively. What is more, these hierarchical hollow materials have a good recycle performance, which will be a great potential material in real applications. Our present work not only provides a method, but also, more importantly, provides a theoretical guide to fabricate the multi-shelled porous hollow materials with hierarchical structures, which can be used in many industrial applications.

CdS nanospheres with an average diameter of 40 nm, mesopores of 11.2 nm and a large specific surface area of 89.66 m2 g−1 are fabricated successfully via a facile method under mild conditions. The as-prepared CdS nanospheres exhibit good performance in the photocatalytic degradation and adsorption activity for organic dyes.

A simple and label-free DNA electrochemical impedance biosensor has been developed for the sequence-specific recognition of double-stranded DNA (ds-DNA). The probe triplex-forming oligonucleotide (TFO) is immobilized on the gold electrode through Au–S interaction. In the presence of the target ds-DNA, the probe TFO interacted with the bases in the major groove of the ds-DNA to form a rigid triplex structure via Hoogsteen hydrogen bonds, leading to an increase of the electron-transfer resistance. It is found that the change of impedance has a linear relationship with the concentration of the target in the range of 0.1–40 nmol L−1, and the detection limit is as low as 0.04 nmol L−1 (S/N = 3).

Chemically designed, hierarchical composite pore materials, with two or more different sized pores arranged regularly and high specific surface area, have attracted considerable attention because of possessing improved functions and applications in chemistry, pharmaceutics, environmental protection and so on. In this study, two biogenic materials, calcium carbonate (CaCO3), the most widely studied biomineral, and lentinan, showing prominent antitumor activity, are incorporated into the biomineralization process to produce CaCO3–lentinan microspheres with hierarchical composite pore structure by the hierarchical assembly of nanoparticles. The pore structure analysis indicated that a wormhole mesoporous structure was present in the framework of the CaCO3–lentinan microspheres and a microporous structure was present in the core part of the mesoporous walls, rendering an unusual hierarchical composite pore structure of CaCO3. The results revealed that the hierarchical composite pore structure could obviously reduce the release rate and prolong the release time of the anticancer drug, which led to minimization of poisonous side effects and decreased bodily injuries due to the stepwise release of the drug from mesoporous pores to micropores. The component CaCO3 with pH-sensitivity could controllably release DOX at the acidic tumour site, which minimizes the spread of toxic drugs around the normal tissues while maximizing tumor-directed drug delivery. In particular, the CaCO3–lentinan microspheres have ideal biocompatibility and biodegradability which are of critical importance for the clinical application. Further investigation also revealed the desirable properties of the CaCO3–lentinan microspheres for the removal of Congo red (CR) pollutant from waste water, with the maximum removal capacity of 213.2 mg g−1, which will be a great potential material in real applications.

Here, hierarchical hollow barium carbonate (BaCO3) with different sizes and morphologies can be obtained by a simple one-pot approach in the presence of soluble starch. Instead of dendritic crystals obtained without soluble starch, the morphology with hierarchical hollow BaCO3 superstructure can be systematically changed from shuttle-like to cauliflower-like with the reaction time. In addition, the highly effective additive also acts as a crystal size-controlled modifier over a range of concentrations. Detailed analysis of the crystal substructures with field-emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) disclose that the hierarchical hollow shuttle-like BaCO3 superstructures are firstly synthesized by self-assembly and Ostwald ripening process. Then, the fractal splitting mechanism is adopted to introduce the synthesis of the hierarchical hollow BaCO3 crystals with different morphologies at the different reaction time. Our present work not only provides a method to fabricate the different morphologies and sizes of BaCO3 particles with hollow superstructures, which can be used in many industrial applications, but also sheds light on the Ostwald ripening and the fractal splitting mechanism of biomimetic mineralization induced by organic additives.

Hydroxyapatite with a flower-like three dimensional architecture was successfully prepared through a facile transformation process of hedgehog-like aragonite precursors. Based on the time-dependent experiments, a possible mechanism was proposed. In addition, the hydroxyapatite assemblies exhibit unique selective adsorption activity for heavy metals.