Shaping Silver Nanoparticles' Size through the Carrier Composition: Synthesis and Antimicrobial Activity.

The increasing resistance of bacteria to conventional antibiotics represents a severe global emergency for human health. The broad-spectrum antibacterial activity of silver has been known for a long time, and silver at the nanoscale shows enhanced antibacterial activity. This has prompted research into the development of silver-based nanomaterials for applications in clinical settings.

Simple engineering of hybrid cellulose nanocrystal-gold nanoparticles results in a functional glyconanomaterial with biomolecular recognition properties.

Cellulose nanocrystal and gold nanoparticles are assembled, in a unique way, to yield a novel modular glyconanomaterial whose surface is then easily engineered with one or two different headgroups, by exploiting a robust click chemistry route. We demonstrate the potential of this approach by conjugating monosaccharide headgroups to the glyconanomaterial and show that the sugars retain their binding capability to C-type lectin receptors, as also directly visualized by cryo-TEM.

Ball milled glyco-graphene oxide conjugates markedly disrupted biofilms.

The engineering of the surface of nanomaterials with bioactive molecules allows controlling their biological identity thus accessing functional materials with tuned physicochemical and biological profiles suited for specific applications. Then, the manufacturing process, by which the nanomaterial surface is grafted, has a significant impact on their development and innovation. In this regard, we report herein the grafting of sugar headgroups on a graphene oxide (GO) surface by exploiting a green manufacturing process that relies on the use of vibrational ball mills, a grinding apparatus in which the energy is transferred to the reacting species through collision with agate spheres inside a closed and vibrating vessel.

Glyco-Coated CdSe/ZnS Quantum Dots as Nanoprobes for Carbonic Anhydrase IX Imaging in Cancer Cells.

The bioimaging of cancer cells by the specific targeting of overexpressed biomarkers is an approach that holds great promise in the identification of selective diagnostic tools. Tumor-associated human carbonic anhydrase (hCA) isoforms IX and XII have been considered so far as well-defined biomarkers, with their expression correlating with cancer progression and aggressiveness. Therefore, the availability of highly performant fluorescent tools tailored for their targeting and able to efficiently visualize such key targets is in high demand.

Novel Synthetic Approach to Heteroatom Doped Polycyclic Aromatic Hydrocarbons: Optimizing the Bottom-Up Approach to Atomically Precise Doped Nanographenes.

The success of the rational bottom-up approach to nanostructured carbon materials and the discovery of the importance of their doping with heteroatoms puts under the spotlight all synthetic organic approaches to polycyclic aromatic hydrocarbons. The construction of atomically precise heteroatom doped nanographenes has evidenced the importance of controlling its geometry and the position of the doping heteroatoms, since these parameters influence their chemical-physical properties and their applications. The growing interest towards this research topic is testified by the large number of works published in this area, which have transformed a once "fundamental research" into applied research at the cutting edge of technology.

Combining cross-coupling reaction and Knoevenagel condensation in the synthesis of glyco-BODIPY probes for DC-SIGN super-resolution bioimaging.

Lectins are involved in a wide range of carbohydrate mediated recognition processes. Therefore, the availability of highly performant fluorescent tools tailored for lectin targeting and able to efficiently track events related to such key targets is in high demand. We report here on the synthesis of the glyco-BODIPYs 1 and 2, based on the efficient combination of a Heck-like cross coupling and a Knoevenagel condensation, which revealed efficient in addressing lectins.

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY.

Mechanochemistry is an emerging and reliable alternative to conventional solution (batch) synthesis of complex molecules under green and solvent-free conditions. In this regard, we report here on the conjugation of a dextran polysaccharide with a fluorescent probe, a phenylboronic acid (PBA)-functionalized boron dipyrromethene (BODIPY) applying the ball milling approach. The ball milling formation of boron esters between PBA BODIPY and dextran proved to be more efficient in terms of reaction time, amount of reactants, and labelling degree compared to the corresponding solution-based synthetic route.

Multiwalled Carbon Nanotubes for Combination Therapy: a Biodistribution and Efficacy Pilot Study.

A drug delivery system (DDS) for combined therapy, based on a short oxidized multiwalled carbon nanotube, is reported. It was prepared exploiting a synthetic approach which allowed loading of two drugs, doxorubicin and metformin, the targeting agent biotin and a radiolabeling tag, to enable labeling with Ga-68 or Cu-64 in order to perform an extensive biodistribution study by PET/CT. The DDS biodistribution profile changes with different administration methods.

Combined therapies with nanostructured carbon materials: there is room still available at the bottom.

The progress of the chemistry of carbon nanotubes (CNT) and graphene derivatives [mainly graphene oxide (GO)] has produced a number of technologically advanced drug delivery systems (DDS) that have been used in the field of nanomedicine, mostly in studies related to oncology. However, such a demanding field of research requires continuous improvements in terms of efficiency, selectivity and versatility. The loading of two, or more, bioactive components on the same nanoparticle offers new possibilities for treating cancer, efficiently addressing issues related both to biodistribution and pharmacokinetics.

Nanostructured carbon materials decorated with organophosphorus moieties: synthesis and application.

A new synthetic approach for the production of carbon nanomaterials (CNM) decorated with organophosphorus moieties is presented. Three different triphenylphosphine oxide (TPPO) derivatives were used to decorate oxidized multiwalled carbon nanotubes (ox-MWCNTs) and graphene platelets (GPs). The TPPOs chosen bear functional groups able to react with the CNMs by Tour reaction (an amino group), nitrene cycloaddition (an azido group) or CuAAC reaction (one terminal C-C triple bond).

Multiwalled carbon nanotubes for drug delivery: Efficiency related to length and incubation time.

Batches of oxidized multiwalled carbon nanotubes differing in length were adopted to prepare two drug delivery systems (DDS) loaded with doxorubicin. The different internalization of the two batches, verified by atomic emission spectroscopy onto cell lysates, was also confirmed by the different toxicity of the same DDS loaded with doxorubicin. In vitro experiments evidenced, after 48h of incubation, the superior efficacy of the shortest nanotubes.

The "click-on-tube" approach for the production of efficient drug carriers based on oxidized multi-walled carbon nanotubes.

To demonstrate the potential of azido-substituted carbon nanotubes for application in nanomedicine, multiple-decorated oxidized multi-walled carbon nanotubes as drug delivery systems have been synthesized. These DDSs were able to carry doxorubicin inside breast MCF-7 cancer cell lines resulting in an enhanced cytotoxic effect with respect to the free drug. Decoration of the carbon nanotubes was accomplished through both covalent and non-covalent approaches: versatile click reactions and π-π interactions were exploited.

Separation of Enantiomers of a Phospholipid in Langmuir Monolayers by a New Selector.

Chiral discrimination in a racemic mixture of dipalmitoylphosphatidylcholine (DPPC) is induced by a new selector at the water-air interface: L-DPPC is segregated in the condensed phase of a Langmuir monolayer upon interactions with an enantiopure amphiphilic compound.

Urea vs. carbamate groups: a comparative study in a chiral C2 symmetric organogelator.

The effect of the replacement of molecular moieties (carbamates vs. urea) that drive self-assembly for two organogelators with an identical C(2) symmetric molecular structure is described. The main properties of the gels obtained from the urea-based organogelators are also discussed.

Azido-Substituted BODIPY Dyes for the Production of Fluorescent Carbon Nanotubes.

A series of azido-dyes were synthesized through Knoevenagel reactions of an azido-BODIPY with aromatic aldehydes. The nature of the substituents allowed the fine tuning of their spectroscopic properties. The dyes were used to decorate oxidized multiwalled carbon nanotubes (ox-MWCNTs), bearing terminal triple bond groups, by CuAAC reactions, affording fluorescent materials.

A Hetero-Bifunctional Spacer for the Smart Engineering of Carbon-Based Nanostructures.

Invited for this month's cover are collaborators from four different Italian research groups, three at the National Research Council (ICCOM, IFAC, and ISOF) and one at the University of Florence. The cover picture shows a representative cartoon of engineered 1D carbon nanomaterials and their effective surface decoration with (bio)molecules and fluorescent markers. Read the full text of the article at 10.

A Hetero-Bifunctional Spacer for the Smart Engineering of Carbon-Based Nanostructures.

Efforts have been made in recent years to develop novel functionalisation protocols aimed at imparting multimodality and improved properties to complex carbon-based nanostructures. The incorporation of cleavable bonds to the nanomaterial surface for the controlled release (or exchange) of specific molecules under appropriate chemical and biological settings is relatively unexplored. The design and synthesis of a hetero-bifunctional linker joining a "cleavable" disulfide moiety for the covalent anchoring of a wide range of thiol end-capped (bio)molecules and a "clickable" terminal acetylene group is described.

Ultrafast resonance energy transfer in the umbelliferone-alizarin bichromophore.

In this work we present the synthesis, time-resolved spectroscopic characterization and computational analysis of a bichromophore composed of two very well-known naturally occurring dyes: 7-hydroxycoumarin (umbelliferone) and 1,2-dihydroxyanthraquinone (alizarin). The umbelliferone donor (Dn) and alizarin acceptor (Ac) moieties are linked to a triazole ring viaσ bonds, providing a flexible structure. By measuring the fluorescence quantum yields and the ultrafast transient absorption spectra we demonstrate the high efficiency (∼85%) and the fast nature (∼1.

Low-generation dendrimers with a calixarene core and based on a chiral C(2)-symmetric pyrrolidine as iminosugar mimics.

The preparation of low-generation dendrimers based on a simple calix[4]arene scaffold by insertion of the iminosugar-analogue C(2)-symmetric 3,4-dihydroxypyrrolidine is described. This methodology allows a rapid incorporation of a considerable number of iminosugar-like moieties in a reduced volume and in a well-defined geometry. The inclusion of alkali-metal ions (sodium and potassium) in the polar cavity defined by the acetamide moieties at the lower rim of the calixarene was demonstrated, which allows also the rigidification of the dendrimer structure and the iminosugar presentation in the clusters.

"Click" on tubes: a versatile approach towards multimodal functionalization of SWCNTs.

Organic functionalization of carbon nanotube sidewalls is a tool of primary importance in material science and nanotechnology, equally from a fundamental and an applicative point of view. Here, an efficient and versatile approach for the organic/organometallic functionalization of single-walled carbon nanotubes (SWCNTs) capable of imparting multimodality to these fundamental nanostructures, is described. Our strategy takes advantage of well-established Cu-mediated acetylene-azide coupling (CuAAC) reactions applied to phenylazido-functionalized SWCNTs for their convenient homo-/heterodecoration with a number of organic/organometallic frameworks, or mixtures thereof, bearing terminal acetylene pendant arms.

A multichromophoric dendrimer: from synthesis to energy up-conversion in a rigid matrix.

A dendrimer with a [Ru(bpy)(3)](2+) (bpy = 2,2'-bipyridine) complex as a core and four diphenylanthracene units at the periphery was prepared from a scaffold based on a bipyridyl ligand bearing four terminal alkyne groups. Upon green light excitation, the dendrimer shows blue luminescence even in a rigid matrix at 77 K thanks to the dendritic multichromophoric structure.

Chirality driven self-assembly in a fluorescent organogel.

In this work, we present the characterization of an enantiomeric pair of fluorescent dye organogelators and the properties of their stable gel at low concentration in organic solvents. The gels of both enantiomers and of their mixtures were analyzed by differential scanning calorimetry, circular dichroism (CD), atomic force microscopy, UV-vis absorption, and fluorescence. The acquired data were supported by molecular modeling of the helical assembly of the gelators and by the simulation of their CD spectra by means of DeVoe method, and suggested the occurrence of an enantiomeric discrimination process during the formation of the gels.