Structurally Defined Water-Soluble Metallofullerene Derivatives towards Biomedical Applications.

Endohedral metallofullerenes (EMFs) are excellent carriers of rare-earth element (REE) ions in biomedical applications because they preclude the release of toxic metal ions. However, existing approaches to synthesize water-soluble EMF derivatives yield mixtures that inhibit precise drug design. Here we report the synthesis of metallobuckytrio (MBT), a three-buckyball system, as a modular platform to develop structurally defined water-soluble EMF derivatives with ligands by choice. Demonstrated with PEG ligands, the resulting water-soluble MBTs show superb biocompatibility. The Gd MBTs exhibit superior T1 relaxivity than typical Gd complexes, potentially superseding current clinical MRI contrast agents in both safety and efficiency. The Lu MBTs generated reactive oxygen species upon light irradiation, showing promise as photosensitizers. With their modular nature to incorporate other ligands, we anticipate the MBT platform to open new paths towards bio-specific REE drugs.

Mixed-Phase 2D-MoS2 as an Effective Photocatalyst for Selective Aerobic Oxidative Coupling of Amines under Visible-Light Irradiation.

Metal-semiconductor heterojunctions play a vital role in photocatalysis, yet their preparation can be exceedingly difficult. The heterojunction helps not only to separate the charges and inhibit recombination processes but also to transfer the photogenerated electron/hole to the reacting molecule. Here, we demonstrate 1T (metallic)-2H (semiconducting) phase boundaries intrinsic to individual sheets of chemically exfoliated 2D-MoS2 can serve as heterojunctions for enhanced photocatalysis in comparison to only semiconducting phase. Due to the abundance of heterojunctions in these multiphasic materials, chemically exfoliated 2D-MoS2 provides improved stability and transfer of photogenerated charges to the reactants, giving better yield. We demonstrate that this easy to synthesize material is an effective photocatalyst for the aerobic oxidative coupling of amines to imines under visible light irradiation. Given its broad applications, we believe mixed phase 2D-MoS2 can be of interest to several industrial synthetic applications related to semiconductor-based photocatalysis. As an added advantage, this heterogeneous photocatalyst can be recycled for several times up to five cycles without any significant loss in the activity.

Water-Soluble Fullerene Monoderivatives for Biomedical Applications.

Monoderivatives of fullerenes functionalized with hydrophilic groups make them water soluble, while preserving the hydrophobic fullerene cage. This class of molecules have intriguing biomedical applications, including drug delivery, photodynamic therapy (PDT), antiviral and antimicrobial activity and reactive oxygen species (ROS)-scavenging abilities. In this Concept we discuss the synthesis and biomedical applications of water-soluble fullerene monoderivatives and their biological behavior based on their structures.

Water-soluble endohedral metallofullerenes: new horizons for biomedical applications.

Endohedral metallofullerenes (EMFs) offer a safe avenue to manipulate metals important to biomedical applications such as MRI contrast, X-ray contrast, radiolabeling, radiotherapy, chemotherapy, and the control of inflammation by scavenging reactive oxygen species (ROS). Moreover, functionalizing the double bonds on the surface of EMFs modifies their solubility, supramolecular behaviour, binding, targeting characteristics, and physical properties. While most existing water-soluble derivatives possess a statistical mixture of appended functional groups, progress has been made in creating molecularly-precise derivatives with a defined number of surface functional groups, leading to potentially more nuanced control of their behaviour and properties. Further elucidation of the structure-function relationships of these materials is expected to enhance their utility in biomedical applications and possibly broaden their use in diverse areas of science and technology.

C60-ß-cyclodextrin conjugates for enhanced nucleus delivery of doxorubicin.

We demonstrate the use of water-soluble C60-ß-cyclodextrin conjugates to encapsulate and deliver doxorubicin to the cell nucleus. The behaviour of the fullerene aggregates inside cells is dictated by the functionalization of the C60 cage. While both the C60 conjugates are taken up by lysosomes upon cellular entry, only the one with a hydroxylated cage rapidly escaped the lysosome. The drug delivery system (DDS) with a hydroxylated C60 cage showed significantly enhanced doxorubicin delivery to the cell nucleus, whereas the DDS with a hydrophobic C60 cage was trapped in the lysosome for a longer time and showed significantly reduced doxorubicin delivery to the nucleus. This study opens new paths towards advanced fullerene-based DDSs for small molecule drugs.