Intelligent phototriggered nanoparticles induce a domino effect for multimodal tumor therapy.

Rationale: Integration of several monotherapies into a single nanosystem can produce remarkable synergistic antitumor effects compared with separate delivery of combination therapies. We developed near-infrared (NIR) light-triggered nanoparticles that induce a domino effect for multimodal tumor therapy. Methods: The designed intelligent phototriggered nanoparticles (IPNs) were composed of a copper sulfide-loaded upconversion nanoparticle core, a thermosensitive and photosensitive enaminitrile molecule (EM) organogel shell loaded with anticancer drugs, and a cancer cell membrane coating. Irradiation with an NIR laser activated a domino effect beginning with photothermal generation by copper sulfide for photothermal therapy that also resulted in phase transformation of the EM gel to release the anticancer drug. Meanwhile, the NIR light energy was converted to ultraviolet light by the upconversion core to excite the EM, which generated reactive oxygen species for photodynamic therapy. Results: IPNs achieved excellent antitumor effects in vitro and in vivo with little systemic toxicity, indicating that IPNs could serve as a safe and high-performance instrument for synergetic antitumor therapy. Conclusion: This intelligent drug delivery system induced a chain reaction generating multiple antitumor therapies after a single stimulus.

Donor acceptor fluorophores: synthesis, optical properties, TD-DFT and cytotoxicity studies.

Donor-π-acceptor (D-π-A) fluorophores consisting of a donor unit, a π linker, and an acceptor moiety have attracted attention in the last decade. In this study, we report the synthesis, characterization, optical properties, TD-DFT, and cytotoxicity studies of 17 near infrared (NIR) D-π-A analogs which have not been reported so far to the best of our knowledge. These fluorophores have chloroacrylic acid as the acceptor unit and various donor units such as indole, benzothiazole, benzo[e]indole, and quinoline. The fluorophores showed strong absorption in the NIR (700-970 nm) region due to their enhanced intramolecular charge transfer (ICT) between chloroacrylic acid and the donor moieties connected with the Vilsmeier-Haack linker. The emission wavelength maxima of the fluorophores were in between 798 and 870 nm. Compound 20 with a 4-quinoline donor moiety showed an emission wavelength above 1000 nm in the NIR II window. The synthesized fluorophores were characterized by 1H NMR and 13C NMR, and their optical properties were studied. Time dependent density functional theory (TD-DFT) calculations showed that the charge transfer occurs from the donor groups (indole, benzothiazole, benzo[e]indole, and quinoline) to the acceptor chloroacrylic acid moiety. Fluorophores with [HOMO] to [LUMO+1] transitions were shown to possess a charge separation character. The cytotoxicity of selected fluorophores, 4, 7, 10 and 12 was investigated against breast cancer cell lines and they showed better activity than the anti-cancer agent docetaxel.

Photodegradation of fluazaindolizine in water under simulated sunlight irradiation: Identification of transformation products and elucidation of transformation mechanism.

The photodegradation of fluazaindolizine in water was investigated under simulated sunlight irradiation. The effects of solution pH, humic acids (HA), nitrates (NO3-) and Fe(III) ions on photolysis of fluazaindolizine were studied. The results indicated that pH did not significantly affect its photodegradation. At low concentration (up to 5 mg/L), HA slightly facilitated the photodegradation of fluazaindolizine, while at high concentration (10-20 mg/L), HA inhibited its photodegradation. The presence of NO3- (0-10 mg/L) and Fe(III) (0-5 mg/L) noticeably accelerated the photodegradation of fluazaindolizine. Moreover, eleven direct transformation products (TPs) were isolated and identified by liquid chromatography quadrupole time-of-flight mass spectrometry. Density functional theory (DFT) calculation was utilized to characterize molecular property of fluazaindolizine and predict the potentiality of the possible photodegradation reaction. Ultimately, a possible transformation mechanism was proposed based on the identified TPs, degradation profiles and DFT calculation. The predominant photoproduct came from ring opening of imidazole-ring and dechlorination. Other TPs resulted from a series of photochemical reactions involving hydroxyl substitution, ring-opening, cleavage, oxidation and decarboxylation. These results were important in elucidating environmental fate of fluazaindolizine in aquatic system and further environmental risk assessment.