Stimuli-Responsive Water-Soluble Fullerene (C60) Polymeric Systems

Preparation of a thermo-responsive drug carrier consisting of a biocompatible triblock copolymer and fullerene

A triblock copolymer (PEG-b-PUEM-b-PMPC; EUM) comprising poly(ethylene glycol) (PEG), thermo-responsive poly(2-ureidoethyl methacrylate) (PUEM), and poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) blocks was synthesized via controlled radical polymerization. PEG and PMPC blocks exhibit hydrophilicity and biocompatibility. The PUEM block exhibits an upper critical solution temperature (UCST). PMPC can dissolve hydrophobic fullerenes in water to form a complex by grinding PMPC and fullerene powders. Fullerene-C₇₀ (C₇₀) and EUM were ground in a mortar and phosphate-buffered saline (PBS) was added to synthesize a water-soluble complex (C₇₀/EUM). C₇₀/EUM has a core-shell-corona structure, whose core is a complex of C₇₀ and PMPC, the shell is PUEM, and corona is PEG. The maximum C₇₀ concentration dissolved in PBS was 0.313 g L^-1 at an EUM concentration of 2 g L^-1. The C₇₀/EUM hydrodynamic radius (R_h) was 34 nm in PBS at 10 °C, which increased due to the PUEM block's UCST phase transition with increasing temperature, and R_h attained a constant value of 38 nm above 36 °C. An anticancer drug, doxorubicin, was encapsulated in the PUEM shell by hydrophobic interactions in C₇₀/EUM at room temperature, which can be released by heating. The generation of singlet oxygen (¹O₂) from C₇₀/EUM upon visible-light irradiation was confirmed using the singlet oxygen sensor green indicator. Water-soluble C₇₀/EUM may be used as a carrier that releases encapsulated drugs when heated and as a photosensitizer for photodynamic therapy.

Mussel-inspired preparation of C60 nanoparticles as photo-driven DNA cleavage reagents

Designing and constructing favorable water-dispersible fullerenes and their derivatives are of huge importance for biological applications addressing DNA-cleavage and photodynamic therapy (PDT).

Synthesis of a [60]fullerene-end-capped polyacetylene derivative – a “rod-sphere” molecule from a “coil-sphere” precursor

A hybrid material composed of a head-to-head substituted polyacetylene end-capped with [60]fullerene was synthesized through anionic polymerization precursor route.

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.

Structural and mechanical characteristics of polymersomes

Polymersomes self-assembled from amphiphilic macromolecules have attracted growing attention because of their multifunctionality and stability. By controlling the structural characteristics of polymersomes, including vesicle shape, size, and membrane thickness, their mechanical and transport properties as well as their fusion behavior can be manipulated. Numerous experimental techniques have been developed to explore polymersome characteristics; however, experimental microscopic observations and knowledge of vesicles are limited. Mesoscale simulations can complement experimental studies of the vesicular features at the microscopic level and thus provide a feasible method to better understand the relationship between the fundamental structures and physicochemical properties of polymersomes. Moreover, the predictive ability of the simulation approaches may greatly assist developments and future applications of polymersomes.

Graphitic nanoparticles from thermal dissociation of camphor as an effective filler in polymeric coatings

Formation of uniformly-sized water soluble graphitic carbon nanoparticles from the soot obtained by the incineration of camphor.

Photo-responsive carbon nanomaterials functionalized by azobenzene moieties: structures, properties and application

The ability to tune the microstructures, bandgap, conductance, chemical environment and thermal storage of carbon nanomaterials such as carbon nanotubes, graphene and fullerenes by optical modulation or response is important to design and fabricate advanced optoelectronic nanodevices. This review is focused on optical control and regulation of structures, properties, interface and interaction of a new generation of photo-responsive carbon nanomaterials/azobenzene moieties (Carbon-AZO) hybrids. The optical switching properties of Carbon-AZO hybrids resulting from the photo-isomerization between trans and cis isomers are highlighted and discussed in terms of photo-energy conversion devices including switches, sensors, detectors, fuels and storage. A wide range of advanced energy conversion devices using Carbon-AZO hybrids can be developed in the future by the optimization of the chemical structure, steric conformation, electrostatic environment and functionalization of specific molecules.