Nanocomposite Organic Nanoparticule

Nanocarrier-mediated photodynamic therapy (PDT) is an effective tool for anti-tumour treatment due to the targeted and image-guided delivery of photosensitizers (PSs) to diseased tissues. These nanocarriers range from inorganic, ceramic, polymeric to biological nanoparticles (NPs). Such PS-grafted bicomponent nanocarriers have limitations like (i) difficulty in surface modification, (ii) lower loading percentages of the therapeutic agent, (iii) unstable physical encapsulation, etc. By any means, if we can prepare PSs directly as NPs then we can surpass the above drawbacks. Hence, we synthesised new two-photon fluorene–functionalised morpholine (Fluo–Mor)-based organic NPs that showed strong fluorescence and profound photodynamic therapy (PDT) activity only in acidic medium. Such a pH-responsive appearance of fluorescence enables Fluo–Mor NPs for the real time monitoring of photodynamic therapeutic activity selectively in low-pH organelles viz. lysosome. Cytotoxicity of Fluo–Mor NPs was monitored using time-dependent and dose-dependent cancer cell viability assay and confocal imaging.

Single component fluorescent organic polymeric nanoparticles (NPs) have been synthesized based on a star shaped 4-arm PEG containing coumarin chromophore for the concomitant employment of photo-dynamic therapy (PDT) and chemotherapy synergistically to wipe out tumour cells with a high efficiency. Polymeric NPs are emerging as the most promising nanoparticulates in the area of drug delivery systems due to their ability to overcome the disadvantages like premature and imprecise control over the drug release, lack of loading capacity etc. Among polymeric NPs, star shaped branched polymers have attracted great attention mainly due to their multiple functionalization properties. Hence, herein we have made use of a multi-arm PEG, functionalized with a targeting unit biotin and a coumarin fluorophore for site-specific and image guided synergic treatment of cancer cells. The anticancer drug chlorambucil is released by the coumarin chromophore in a photocontrolled manner. In addition to that, coumarin also generated singlet oxygen upon irradiation with UV/vis light (≥365 nm) with a moderate quantum yield of ∼0.37. In vitro application of thus prepared organic polymeric nanoparticles (PEG–Bio–Cou–Cbl) in the HeLa cell line shows a reduction of cell viability by up to ∼5% in the case of a combined treatment of PDT and chemotherapy whereas analogous organic polymeric NPs without the chemotherapeutic drug (PEG– Bio–Cou) result in ∼49% cell viability by means of PDT process only.