Multifunctional Janus Nanoparticles Enabling Sequential Spatio-Selective Biofunctionalization for Novel Therapeutic Applications:
Cancer is the second most common cause of death in the US; however, the mortality rate can be often greatly reduced by early diagnosis and therapy. One of our goals is to utilize the MRI-contrast agent-based anisotropic nanoparticles as platforms for spatio-selective growth of two-photon excitation-based photodynamic therapy (PDT) photosensitizers (PSs) incorporated in photosensitizer-based thin films followed by decoration of the other half of the nanoparticles with biofunctionalities or drugs carriers. While the MRI contrast agent core enables monitoring changes in tumor diffusion, the targeting ligands leads to selective binding to tumor cells and the PS-generated singlet oxygen results in regional necrosis. This approach enables simultaneous cancer imaging, detection, and therapy with a single nanoparticle and addresses the current issues in PDT such as light penetration depth, aggregation and targeting.
The synthesis and characterization of organometallic and coordination compounds of transition metals (mainly Platinum and Gold) and their study of biological and luminescent properties based on advances in fundamental sciences:
I) Design and study of the properties of organoplatinum complexes and potential applications: The goal of this research line is focused on the preparation and structural characterization of novel organoplatinum compounds by using of platinum(II) electron-rich derivatives as starting materials. The optical properties (absorption and emission) of these new organoplatinum complexes are investigated. In some cases these complexes reveal biological application such as bio-imaging. Therefore, in this manner more stable and biologically compatible organoplatinum complexes can be selected in order to reach the biological aims better. Besides biological activity, possible mechanisms of action will be considered by means of studying coordination of platinum to the DNA, the analysis of their anticancer activity. A further topic is kinetic and mechanistic studies (by UV-vis or NMR spectroscopies) on the activation of various C-X bonds with these organoplatinum complexes.
II) Gold complexes: chemical biology: This research is a platform for synthesis and characterization of the new gold(I) compounds (especially gold(I)-thiolate complexes) and significant potential of these complexes as anti-cancer or anti-microbial. This area includes computer-aided drug design. Also, some of these gold complexes have ability to form heterometallic complexes by another metal such as platinum. These heterometallic complexes may be promising candidates with improved luminescence and antitumor properties with respect to their monometallic precursors.
Spatially-Resolved Nature-Inspired Functional Materials to Solve Catalyst-Catalyst Incompatibility:
To achieve efficient catalytic reactions, chemists have sought multi-step tandem processes using multi-catalytic homogeneous systems. However, catalyst deactivation from catalyst-catalyst incompatibility is a major problem. As exemplified by many catalytic enzyme assemblies, catalyst site-isolation is a powerful strategy for performing tandem catalytic reactions. One of our aims is to obtain biomimetic materials by exploiting porous nanomaterials thin films to create useful site-isolated multi-functional catalysts that are inherently inaccessible in analogous homogeneous systems and, indeed, unprecedented in catalysis.
We are working on solutions based on high-precision nanofabrication techniques e.g. molecular epitaxy to the catalyst-catalyst incompatibility problem by spatially fixing the incompatible catalysts in nano-scale proximity. We aim to demonstrate the applicability of our approach as a powerful tool to the current catalytic challenges, especially in the area of energy sustainability in particular photocatalytic hydroformylation–hydrogenation and hydrocarbon elongation, as well as the area of radiochemistry (Positron Emission Tomography) for biomedical imaging.
Ultrastable Functional Materials as Catalysts for Tandem Small Molecule Activation:
Preparation of ultrastable functional catalytic thin films based on the utilization of transition metal oxoclusters as secondary building units (SBUs) is one of our interests. The approach enables the formation of non-pillared paddlewheel-based topologies in an epitaxial fashion for the first time leading to novel applications such as catalysis under non-ambient conditions e.g. acidic/basic pHs or high temperatures that are not tolerated by other materials. As such, a tandem nature-inspired pH switchable hydrogen storage using carbon dioxide to formic acid followed by formic acid hydrogenation to methanol is one of our interests:
In addition, the resulting unique node structures within the thin films allows for single-site metalation of nodes leading to well-defined single-site catalytic centers for tandem reactions in the synthesis of biologically interesting compounds and small molecule activation.