Supramolecular metallopolymer for hypoxia-activated ruthenium complexes delivery and smart chemo-photodynamic therapy

The Ru complexes have garnered a great deal of attention for antitumor phototherapy;however, achieving efficient cellular uptake and tumor-specific activation represents a major challenge. Herein, we synthesize a hypoxia-activated Ru complex(Ru ANM) and construct it into supramolecular polymers(Poly Ru ANM) through high binding affinity interaction. The amphiphilic supramolecular polymers possess self-assembly, resulting in the formation of diverse nanostructures exhibiting a range of morphologies by simply adjusting the host-guest ratio. As the polymer nanostructure size and morphology have been optimized, Poly Ru ANM prevents premature drug leakage and accumulates rapidly in the tumor cells. In the tumor hypoxia microenvironment, the polymer undergoes selective activation and disintegration, leading to the unlock of Ru complexes.Notably, the subsequent application of red light irradiation exacerbates the hypoxia and potentiates the liberation of the Ru complexes. This polymer design concept provides some novel insights into on-demand drug delivery and smart chemophotodynamic therapy.

Hydrogen self-supplying initiators excited by visible light for the fabrication of transparent films

Unimolecular Type Ⅱ radical photoinitiators(PIs) have received significant attention in photocuring owing to the fact that they improve the sustainability of the overall process compared with traditional Type Ⅱ radical photoinitiators. However, the photopolymerization efficiency of unimolecular Type Ⅱ radical photoinitiators is hindered by their short excitation wavelengths,poor photon capture abilities, and inefficient photobleaching performance. Herein, we report a coumarin-based self-sufficient initiator(C-NA), which is designed by integrating “hydrogen donor” and “hydrogen acceptor” into the coumarin framework and used for single-component visible light curing. C-NA exhibits a visible light absorbance and high molar extinction coefficient and is completely photobleached under the irradiation of 405 nm light-emitting diodes(LEDs). The formation of free radicals arises from the transfer of hydrogen from the diethylamino group to the coumarin framework, together with a highly efficient photodegradation process of C-NA. Finally, C-NA was successfully applied to prepare a transparent film material. Therefore,C-NA offers new insights into the design of promising unimolecular Type Ⅱ radical photoinitiators for photocuring.