Communications separating the PPV-rich parts and the pyridine-rich segments. This will be explained in more detail elsewhere.The significant red emission at high voltages is probably associated with the higher efficiency for light emission in pyridine-rich segments. As demonstrated by OnodaI7] the EL efficiency for light emission from PPyV is rather high (7 N 0.5 YO ) and it is further enhanced due to the presence of the junctionsr7 in PPV/PPyV. At the present time, we cannot exclude alternative explanations associated with the formation of exciton or impurity bands in the x-x* forbidden gap of PPV upon substitution of the pyridine moieties in the copolymer. ExperimentalThe 2,6-pyridyl-dimethylene-bis-(tetramethylene sulfonium chloride) monomer was prepared by adding tetrahydrothiophene (THT) (15 ml) to 2,6bis(chloromethy1)-pyridine (5 g) in methanol (150 ml). The reaction mixture was kept at 50°C for 4 days and was then concentrated to gelation. The hissulfonium salt was precipitated by addition of ice cold acetone (250 ml) and was isolated. The 1,4-phenylenedimethylene-bis-(tetramethylene sulfonium chloride) was prepared according to the literature procedure. The copolymerization was typically carried out as follows. A mixture of 20 YO (molar) of 2,6pyridyl-dimethylene-bis-(tetramethylene sulfonium chloride) (1.49 g) and 1,4phenylene dimethylene-bis-(tetramethylene sulfonium chloride) (5.96 g) in water (200 ml) was prepared. Polymerization was initiated under nitrogen at 0-2°C by addition of a stoichiometric quantity of 1 N NaOH in water (21.2 ml) under constant vigorous stirring for 1 h. The mixture was neutralized with 1 N HCl(9.4 ml) corresponding to 54.2 % conversion of the monomers to the copolyelectrolyte. The copolyelectrolyte solution was homogenized and dialyzed (Mw cut-off 12000) at 4°C for ten days.Films for the various measurements were prepared by casting the dialyzed copolyelectrolyte on relevant substrates by spin coating. The polyelectrolyte was then converted to the final copolymer, co(2,6PyV-PV) by heating in vacuum, 10-6torr, at 280°C for 12 h. Film thicknesses were determined by X-ray reflectivity at grazing angle using a 12 kW Rigaku rotating anode and found to be approximately 1000 A. Absorption spectra were measured on a HP 8452 diode array spectrometer. PL spectra were recorded on Perkin Elmer Luminescence Spectrometer LS 50. EL spectra were recorded using an Oriel monochromator and the light intensity was quantified with a photo-multiplier (products from Research Inc. model no. R955).

Photodynamic therapy (PDT) is traditionally ineffective for deeply embedded tumors due to the poor penetration depth of the excitation light. Chemiluminescence resonance energy transfer (CRET) has emerged as a promising mode of PDT without external light. To date, related research has frequently used endogenous hydrogen peroxide (H 2 O 2 ) and oxygen (O 2 ) inside the solid tumor microenvironment to trigger CRET-mediated PDT. Unfortunately, this significantly restricts treatment efficacy and the development of further biomedical applications because of the limited amounts of endogenous H 2 O 2 and O 2 . Herein, a nanohybrid (mSiO 2 /CaO 2 /CPPO/Ce6: mSCCC) nanoparticle (NP) is designed to achieve synergistic CRET-mediated PDT and calcium (Ca 2+ )-overload-mediated therapy. The calcium peroxide (CaO 2 ) formed inside mesoporous SiO 2 (mSC) with the inclusion of the chemiluminescent agent (CPPO) and photosensitizer (Ce6) self-supplies H 2 O 2 , O 2 , and Ca 2+ allowing for the subsequent treatments. The Ce6 in mSCCC NPs is excited by chemical energy in situ following the supply of H 2 O 2 and O 2 to produce singlet oxygen ( 1 O 2 ). The nanohybrid NPs are coated with stearic acid to avoid decomposition during blood circulation through contact with aqueous environment. This nanohybrid shows promising performance in the generation of 1 O 2 for external light-free PDT and the release of Ca 2+ ions for Ca 2+ -overloaded therapy against orthotopic hepatocellular carcinoma.

Photodynamic Therapies In article 2201613 by Chia‐Hao Su, Chen‐Sheng Yeh, and co‐workers, the concept of self‐supplying H2O2 and O2 is presented by an all‐in‐one nanoreactor to process H2O2 and O2 generation, chemiluminescence resonance energy transfer (CRET) activated by the generated H2O2, and energy‐transfer to excite photosensitizer resulting in singlet oxygen formation. This allows the conduction of an external light‐fee CRET‐mediated photodynamic therapy, ushering in a new era in light‐based therapeutic interventions.