Synthesis and Characterization of Highly Water-Soluble Dendrofulleropyrrolidine Bisadducts with DNA Binding Activity

Corannulene Amino Acid-Derived Water-Soluble Amphiphilic Buckybowls as Broad-Spectrum Membrane Targeting Antibacterial Agents

To date, the use of corannulene has been restricted in the area of material science, but its application in biomedical research has yet to be established due to its nonsolubility in an aqueous environment and synthetic infeasibility. Herein, we detail the development of a new family of highly curved π-conjugated corannulene-containing unnatural α-amino acid (CAA) derivatives to overcome this challenge. These CAAs have been extended as novel constituents for the synthesis of corannulene-containing water-soluble cationic peptides (CCPs), which display inhibitory activity against broad-spectrum pathogenic bacteria along with drug-resistant bacteria via a membrane-damaging mechanism. Importantly, several of the synthesized peptides were found to be appreciably nonhemolytic against hRBCs and noncytotoxic against mammalian 3T3 cells. In vivo efficacy studies of the potent and least cytotoxic peptide 6a demonstrated clearance of bacteria from the spleen, liver, lung, and blood of mice infected with S. aureus ATCC 25923.

Click synthesis of dendronized malonates for the preparation of amphiphilic dendro[60]fullerenes

Fullerene C60 and its malonate derivatives, produced via the Bingel-Hirsch reaction, have displayed promising properties against various diseases. These molecules have great therapeutic potential, but their broad use has been limited due to poor aqueous solubility and toxicity caused by accumulation. In this study, we synthesized new malonates and malonamides attached to first- and second-generation polyester dendrons using click chemistry (CuAAC). These dendrons were then linked at C60 through the Bingel-Hirsch reaction, resulting in an amphiphilic system that retains the hydrophobic nature of C60. The dendronized malonate derivatives showed good reaction yields for the Bingel-Hirsch mono-adducts and were easier to work with than the corresponding malonamides. However, the malonamide derivatives, which were obtained through a multistep reaction sequence, showed moderate yields in the Bingel-Hirsch reaction. Surprisingly, removing acetonide protecting groups from dendritic architectures was more challenging than anticipated, likely due to product decomposition. Only the corresponding free malonate derivatives 25 and 26 were obtained, but in a low yield due to decomposition under the reaction conditions. Meanwhile, it was not possible to obtain the corresponding malonamide derivatives 27 and 28. Currently, efforts are being made to improve the production of the desired molecules and to design new synthesis routes that allow direct access to the desired poly-hydroxylated derivatives. These derivatives will be evaluated as multitarget ligands against Alzheimer's disease, through their use as inhibitors of amyloid β-peptide aggregation, acetylcholinesterase modulators, and antioxidants.

Multivalent cationic dendrofullerenes for gene transfer: synthesis and DNA complexation

Non-viral nucleic acid vectors able to display high transfection efficiencies with low toxicity and overcoming the multiple biological barriers are needed to further develop the clinical applications of gene therapy. The synthesis of hexakis-adducts of [60]fullerene endowed with 12, 24 and 36 positive ammonium groups and a tridecafullerene appended with 120 positive charges has been performed. The delivery of a plasmid containing the green fluorescent protein (EGFP) gene into HEK293 (Human Embryonic Kidney) cells resulting in effective gene expression has demonstrated the efficacy of these compounds to form polyplexes with DNA. Particularly, giant tridecafullerene macromolecules have shown higher efficiency in the complexation and transfection of DNA. Thus, they can be considered as promising non-viral vectors for transfection purposes.

Triazine-Based Janus G-C Nucleobase as a Building Block for Self-Assembly, Peptide Nucleic Acids, and Smart Polymers

This communication reports on the utility of a triazine-based self-assembling system, reminiscent of a Janus G-C nucleobase, as a building block for developing (1) supramolecular polymers, (2) peptide nucleic acids (PNAs), and (3) smart polymers. The strategically positioned self-complementary triple H-bonding arrays DDA and AAD facilitate efficient self-assembly, leading to a linear supramolecular polymer.

Fullerene-ionic-liquid conjugates: a new class of hybrid materials with unprecedented properties

A modular approach has been followed for the synthesis of a series of fullerene-ionic-liquid (IL) hybrids in which the number of IL moieties (two or twelve), anion, and cation have been varied. The combination of C60 and IL give rise to new unique properties in the conjugates such as solubility in water, which was higher than 800 mg mL(-1) in several cases. In addition, one of the C60 -IL hybrids has been employed for the immobilization of palladium nanoparticles through ion exchange followed by reduction with sodium borohydride. Surprisingly, during the reduction several carbon nanostructures were formed that comprised nano-onions and nanocages with few-layer graphene sidewalls, which have been characterized by means of thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray analysis (SEM-EDAX), and high-resolution transmission electron microscopy (HRTEM). Finally, the material thus obtained was successfully applied as catalyst in Suzuki and Mizoroki-Heck reactions in a concentration of just 0.2 mol %. In the former process it was recyclable for five runs with no loss in activity.

[60]Fullerenyl amino acids and peptides: a review of their synthesis and applications

This review reports on the latest progress in the synthesis of fullerenyl amino acids and related derivatives, and categorises the molecules into functional types for different uses: these include directly attached fullerenyl amino acids, fullerenyl N- and C-capping amino acids, and those amino acids in which the [60]fullerene group is attached to the amino acid side chain.

Knitting the catalytic pattern of artificial photosynthesis to a hybrid graphene nanotexture

The artificial leaf project calls for new materials enabling multielectron catalysis with minimal overpotential, high turnover frequency, and long-term stability. Is graphene a better material than carbon nanotubes to enhance water oxidation catalysis for energy applications? Here we show that functionalized graphene with a tailored distribution of polycationic, quaternized, ammonium pendants provides an sp(2) carbon nanoplatform to anchor a totally inorganic tetraruthenate catalyst, mimicking the oxygen evolving center of natural PSII. The resulting hybrid material displays oxygen evolution at overpotential as low as 300 mV at neutral pH with negligible loss of performance after 4 h testing. This multilayer electroactive asset enhances the turnover frequency by 1 order of magnitude with respect to the isolated catalyst, and provides a definite up-grade of the carbon nanotube material, with a similar surface functionalization. Our innovation is based on a noninvasive, synthetic protocol for graphene functionalization that goes beyond the ill-defined oxidation-reduction methods, allowing a definite control of the surface properties.