A Pd-labile fluoroquinolone prodrug efficiently prevents biofilm formation on coated surfaces.

Surface-adhered bacteria on implants represent a major challenge for antibiotic treatment. We introduce hydrogel-coated surfaces loaded with tailored Pd-nanosheets which catalyze the release of antibiotics from inactive prodrugs. Masked and antibiotically inactive fluoroquinolone analogs were efficiently activated at the surface and prevented the formation of biofilms.

Bioorthogonal Catalysis by Encapsulated Nanoalloys: Overcoming Intracellular Deactivation.

Bioorthogonal metallocatalysis has opened up a xenobiotic route to perform nonenzymatic catalytic transformations in living settings. Despite their promising features, most metals are deactivated inside cells by a myriad of reactive biomolecules, including biogenic thiols, thereby limiting the catalytic functioning of these abiotic reagents. Here we report the development of cytocompatible alloyed nanoparticles with the capacity to elicit bioorthogonal depropargylations with high efficiency in biological media.

Truly-Biocompatible Gold Catalysis Enables Vivo-Orthogonal Intra-CNS Release of Anxiolytics.

Being recognized as the best-tolerated of all metals, the catalytic potential of gold (Au) has thus far been hindered by the ubiquitous presence of thiols in organisms. Herein we report the development of a truly-catalytic Au-polymer composite by assembling ultrasmall Au-nanoparticles at the protein-repelling outer layer of a co-polymer scaffold via electrostatic loading. Illustrating the in vivo-compatibility of the novel catalysts, we show their capacity to uncage the anxiolytic agent fluoxetine at the central nervous system (CNS) of developing zebrafish, influencing their swim pattern.

Truly-Biocompatible Gold Catalysis Enables Vivo-Orthogonal Intra-CNS Release of Anxiolytics.

Being recognized as the best-tolerated of all metals, the catalytic potential of gold (Au) has thus far been hindered by the ubiquitous presence of thiols in organisms. Herein we report the development of a truly-catalytic Au-polymer composite by assembling ultrasmall Au-nanoparticles at the protein-repelling outer layer of a co-polymer scaffold via electrostatic loading. Illustrating the in vivo-compatibility of the novel catalysts, we show their capacity to uncage the anxiolytic agent fluoxetine at the central nervous system (CNS) of developing zebrafish, influencing their swim pattern.

Transition metal catalysts for the bioorthogonal synthesis of bioactive agents.

The incorporation of abiotic transition metal catalysis into the chemical biology space has significantly expanded the tool kit of bioorthogonal chemistries accessible for cell culture and in vivo applications. A rich variety of homogeneous and heterogeneous catalysts has shown functional compatibility with physiological conditions and biostability in complex environs, enabling their exploitation as extracellular or intracellular factories of bioactive agents. Current trends in the field are focusing on investigating new metals and sophisticated catalytic devices and toward more applied activities, such as the integration of subcellular, cell- and site-targeting capabilities or the exploration of novel biomedical applications.

Upconverting Carbon Nanodots from Ethylenediaminetetraacetic Acid (EDTA) as Near-Infrared Activated Phototheranostic Agents.

This work describes the synthesis of nitrogen-doped carbon nanodots (CNDs) synthesized from ethylenediaminetetraacetic acid (EDTA) as a precursor and their application as luminescent agents with a dual-mode theranostic role as near-infrared (NIR) triggered imaging and photodynamic therapy agents. Interestingly, these fluorescent CNDs are more rapidly and selectively internalized by tumor cells and exhibit very limited cytotoxicity until remotely activated with a NIR illumination source. These CNDs are excellent candidates for phototheranostic purposes, for example, simultaneous imaging and therapy can be carried out on cancer cells by using their luminescent properties and the in situ generation of reactive oxidative species (ROS) upon excitation in the NIR range.

Luminescent mesoporous nanorods as photocatalytic enzyme-like peroxidase surrogates.

Herein we report on a novel inorganic peroxidase-mimicking nanocatalyst activated under blue LED photoirradiation. A novel flash-pyrolysis method has been developed for the generation of strong blue photoluminescence (PL) centers attributed to silicon and carbon-based sites within a mesoporous SBA-15 silica nanorod platform. The type of centers and their PL response can be controlled by varying the flash thermal treatment conditions.

Pumping Metallic Nanoparticles with Spatial Precision within Magnetic Mesoporous Platforms: 3D Characterization and Catalytic Application.

The present work shows an efficient strategy to assemble two types of functional nanoparticles onto mesoporous MCM-41 silica nanospheres with a high degree of spatial precision. In a first stage, magnetite nanoparticles are synthesized with a size larger than the support pores and grafted covalently through a peptide-like bonding onto their external surface. This endowed the silica nanoparticles with a strong superparamagnetic response, while preserving the highly ordered interior space for the encapsulation of other functional guest species.

Nitrogen-Induced Transformation of Vitamin C into Multifunctional Up-converting Carbon Nanodots in the Visible-NIR Range.

Water-soluble, biocompatible, and photoluminescent carbon nanodots have been obtained from the rationalized carbonization of vitamin C, a well-known antioxidant molecule in the presence of an amine co-reactant. Herein, we describe the positive influence of N-doping to induce a unique pH-dependent lifetime decay response that would be potentially attractive in biological backgrounds with intrinsic fluorescence fluctuations. In addition, the selectivity and sensitivity of the N-containing carbon nanoprobes towards the detection of copper ions at ppm levels is critically enhanced in comparison with the un-doped counterpart, especially in the near-infrared (NIR) range.

Titania-coated gold nanorods with expanded photocatalytic response. Enzyme-like glucose oxidation under near-infrared illumination.

Gold nanorods coated with a uniform titanium dioxide nanoshell have been prepared and used as glucose-oxidase surrogates. Remarkably, this core-shell photocatalytic nanostructure has been able to induce complete oxidation of glucose at near room temperature (32-34 °C) in a wide range of pH values with the aid of a near-infrared (NIR) irradiation source. In contrast, the uncoated gold nanorods exhibit negligible photo-oxidation response under identical experimental conditions thereby proving the photoactivity of the titania shell towards glucose oxidation.

Feroxyhyte nanoflakes coupled to up-converting carbon nanodots: a highly active, magnetically recoverable, Fenton-like photocatalyst in the visible-NIR range.

We demonstrate the enhanced photocatalytic response of a novel Fenton-like heterogeneous catalyst obtained through the assembly of superparamagnetic feroxyhyte nanoflakes synthesized by continuous gas-slug microfluidics and carbon nanodots obtained by pyrolysis from a natural organic source. The novel nanohybrids enable the utilization of the visible and near-infrared ranges due to the active role of the carbon nanodots as up-converting photo-sensitizers. This novel photocatalyst is magnetically recoverable and maintains an excellent response after multiple reutilization cycles.