A P-61 Black Widow Inspired Palladium Biladiene Complex for Efficient Sensitization of Singlet Oxygen Using Visible Light

Photodynamic therapy (PDT) is a promising treatment option that ablates cancerous cells and tumors via photoinduced sensitization of singlet oxygen. Over the last few decades, much work has been devoted to the development of new photochemotherapeutic agents for PDT. A wide variety of macrocyclic tetrapyrrole based photosensitizers have been designed, synthesized and characterized as PDT agents. Many of these complexes have a variety of issues that pose a barrier to their use in humans, including biocompatibility, inherent toxicity, and synthetic hurdles. We have developed a non-traditional, non-cyclic, and non-aromatic tetrapyrrole ligand scaffold, called the biladiene (DMBil1), as an alternative to these traditional photosensitizer complexes. Upon insertion of a heavy atom such as Pd2+ center, Pd[DMBil1] generates singlet oxygen in substantial yields (ΦΔ = 0.54, λexc = 500 nm) when irradiated with visible light. To extend the absorption profile for Pd[DMBil1] deeper into the phototherapeutic window, the tetrapyrrole was conjugated with alkynyl phenyl groups at the 2- and 18-positions (Pd[DMBil2-PE]) resulting in a significant redshift while also increasing singlet oxygen generation (ΦΔ = 0.59, 600 nm). To further modify the dialkynyl-biladiene scaffold, we conjugated a 1,8-diethynylanthracene with to the Pd[DMBil1] tetrapyrrole in order to further extend the compound’s π-conjugation in a cyclic loop that spans the entire tetrapyrrole unit. This new compound (Pd[DMBil2-P61]) is structurally reminiscent of the P61 Black Widow aircraft and absorbs light into the phototherapeutic window (600–900 nm). In addition to detailing the solid-state structure and steady-state spectroscopic properties for this new biladiene, photochemical sensitization studies demonstrated that Pd[DMBil2-P61] can sensitize the formation of 1O2 with quantum yields of ΦΔ = 0.84 upon irradiation with light λ = 600 nm. These results distinguish the Pd[DMBil2-P61] platform as the most efficient biladiene-based singlet oxygen photosensitizer developed to date. When taken together, the improved absorption in the phototherapeutic window and high singlet oxygen sensitization efficiency of Pd[DMBil2-P61] mark this compound as a promising candidate for future study as an agent of photodynamic cancer therapy.

Chiroptical property enhancement of chiral Eu(III) complex upon association with DNA-CTMA

DNA-based materials have attracted much attention due to their unique photo-functional properties and potential applications in various fields such as luminescent and biological systems, nanodevices, etc. In this study, the photophysical properties of a chiral Eu(III) complex, namely (Eu(D-facam)3), within DNA films were extensively investigated. The enhancement of photoluminescence (more than 25-folds increase of luminescence quantum yield) and degree of circularly polarization in luminescence (glum = − 0.6) was observed upon interaction with DNA. Various photophysical analyses suggested that the emission enhancement was mainly due to an increase of the sensitization efficiency (high ηsens) from the ligands to Eu(III) and suppression of the vibrational deactivation upon immobilization onto the DNA molecule. From CD and VCD measurements, it was suggested that the coordination structure of Eu(D-facam)3 was affected by the interaction with DNA, suggesting that the structural change of Eu(D-facam)3 contributed to the improvement of its luminescent properties.

Development of a Simple Assay Method for Adenosine Deaminase via Enzymatic Formation of an Inosine-Tb3+ Complex

Adenosine deaminase (ADA), which catalyzes the irreversible deamination of adenosine to inosine, is related to various human diseases such as tuberculous peritonitis and leukemia. Therefore, the method used to detect ADA activity and screen the effectiveness of various inhibitor candidates has important implications for the diagnosis treatment for various human diseases. A simple and rapid assay method for ADA, based on the enzymatic formation of a luminescent lanthanide complex, is proposed in this study. Inosine, an enzymatic product of ADA with stronger sensitization efficiency for Tb3+ than adenosine, produced a strong luminescence by forming an inosine-Tb3+ complex, and it enabled the direct monitoring of ADA activity in real-time. By introducing only Tb3+ to adenosine and ADA in the buffer, the enhancement of luminescence enabled the detection of a low concentration of ADA (detection limit 1.6 U/L). Moreover, this method could accurately determine the inhibition efficiency (IC50) of the known ADA inhibitor, erhythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), and the inhibition of ADA could be confirmed by the naked eye. Considering its simplicity, this assay could be extended to the high-throughput screening of various ADA inhibitor candidates.

Strong upconversion emission in CsPbBr3 perovskite quantum dots through efficient BaYF5:Yb,Ln sensitization

An in situ growth method was proved to realize full sensitization efficiency of all-inorganic CsPbBr3 perovskite quantum dots from lanthanide-based upconversion nanoparticles, leading to intense emission intensity.

Conversion of blue light to near infrared emission by Y3Al5O12: Ce3+, Er3+, Ho3+

Ho[Formula: see text] single-doped, Ce[Formula: see text]/Ho[Formula: see text] co-doped and Ce[Formula: see text]/Er[Formula: see text]/Ho[Formula: see text] tri-doped Y3Al5O[Formula: see text] (YAG) near infrared (NIR) phosphors were prepared by coprecipitation-melted salt method. The 2090[Formula: see text]nm emission of Ho[Formula: see text] is improved by 2 times in Ce[Formula: see text]/Er[Formula: see text]/Ho[Formula: see text] tri-doped YAG phosphor and by 0.5 times in Ce[Formula: see text]/Ho[Formula: see text] co-doped YAG phosphor, compared with that in Ho[Formula: see text] single-doped YAG phosphor. The improved luminescence at 2090[Formula: see text]nm in Ce[Formula: see text]/Er[Formula: see text]/Ho[Formula: see text] tri-doped YAG phosphor is performed by the Ce[Formula: see text] indirect sensitization. It is estimated that the Ce[Formula: see text] indirect sensitization efficiency is about 64% in the Y[Formula: see text]Al5O[Formula: see text]:0.06Ce, 0.15Er, 0.14Ho sample.

Enhancing the sensitization efficiency of erbium doped organic complexes by heavy halogen substitution

Photosensitisation of IR luminescence from an organic erbium complex is much greater with Zn(Cl-FBTZ)2 than with Zn(FBTZ)2.