High performance near-IR-active macro- and nano-Metal-Organic-Frameworks using organic dyes

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This research consists at designing nano-sized porous materials exhibiting multiple functions. First, these porous*materials are built with an inorganic part called node and a rigid organic unit. Together, they form a 3-dimensional*porous frame of various forms and cavity sizes. This material belongs to the family of coordination polymers, more specifically to*metal-organic-frameworks (MOFs). Thus, the voids*created by this assembly can be filled with molecules making them cargos. The*word coordination means that the link between the metal and organic parts is*a coordination bond, which is weaker than a covalent one. This relative*fragility can be used to trigger a breakdown of the framework, therefore a release*of the molecules inside the cargos (i.e. drug delivery). Second, the*specificity of the proposal is that the organic units are dyes absorbing and*emitting in the phototherapeutic window (650-850 nm) with an optimum position*at 800 nm where light penetrates best through skin (note that the near-IR*region is 780-2500 nm). In simple words, one can trigger a drug release from the*outside of the patient using a radiation of 650-850 nm range. Moreover, the emission*from the dye inside an organ can best escape at 800 nm and be detected outside*the patient by a near-IR detector. This process is called optical imaging.*Third, some dyes can absorb light and heat to up the point that the MOFs breaks down (because of the weakness of the coordination bond). Also the*increase in heat by itself can also cause dammage to the living cells. It is*called photothermal therapy. Fourth, oxygen is everywhere. These dyes also have*the capacity to absorb light and transfer its energy to oxygen by simple*contact or collision. Upon energy transfer, oxygen becomes singlet oxygen*(gained energy) and is very toxic to living cell. This process is called*photodynamic therapy. Interestingly, once the MOF is broken down, the dye is intact*and can still be photo-active for the generation of singlet oxygen. With the*appropriate dye or dyes, the construction of nano-MOFs (for medical*applications as this size is appropriate to penetrate the living cells) requires*only a few steps and will exhibit four target functions : imaging, drug delivery,*photothermal and photodynamic therapy. This is a new concept four in one, three of them are designed to*kill cancer cells. Because MOFs are easily modifyable at their surface,*recognition receptors (to recognize the cancer cells) and near-IR emissive dyes*can be anchored on.