Influence of Block Ratio on Thermal, Optical, and Photovoltaic Properties of Poly(3-hexylthiophene)-b-poly(3-butylthiophene)-b-poly(3-octylthiophene).

Efforts to improve the solar power conversion efficiencies of binary bulk heterojunction-type organic photovoltaic devices using an active layer consisting of a poly-(3-alkylthiophene) (P3AT) homopolymer and a suitable fullerene derivative face barriers caused by the intrinsic properties of homopolymers. To overcome such barriers, researchers might be able to chemically tailor homopolymers by means of monomer ratio-balanced block copolymerization to obtain preferable properties. Triblock copolymers consisting of three components-3-hexylthiophene (HT), 3-butylthiophene (BT), and 3-octylthiophene (OT)-were synthesized via Grignard metathesis (GRIM) polymerization. The component ratios of the synthesized block copolymers were virtually the same as the feeding ratios of the monomers, a fact which was verified using 1H-NMR spectra. All the copolymers exhibited comparable crystalline and melting temperatures, which increased when one type of monomer became dominant. In addition, their power conversion efficiencies and photoluminescence properties were governed by the major components of the copolymers. Interestingly, the HT component-dominated block copolymer indicated the highest power conversion efficiency, comparable to that of its homopolymer, although its molecular weight was significantly shorter.

PEGylated-Paclitaxel and Dihydroartemisinin Nanoparticles for Simultaneously Delivering Paclitaxel and Dihydroartemisinin to Colorectal Cancer.

PURPOSE: Development of a nanoplatform constructed by the PEG-dual drug conjugation for co-delivery of paclitaxel (PTX) and Dihydroartemisinin (DHA) to the tumor. METHODS: PEG was conjugated with PTX and DHA to form PTX-PEG-DHA complex as a nanocarrier. The PTX and DHA were co-encapsulated in PTX-PEG-DHA nanoparticles (PD@PPD NPs) by the emulsion evaporation method. The physicochemical properties of PD@PPD Nps were characterized, including size, zeta potential, and morphology. The drug loading capacity and entrapment efficiency, in vitro drug release at different pH conditions were also evaluated. For in vitro assessment, the effects of the NPs on HT-29 colorectal cancer cells, including intracellular uptake, cytotoxicity, and Bcl-2 protein expression were assessed. The in vivo distribution of the NPs was investigated by labelling the NPs with Cyanine 5.5 fluorophore. Finally, the antitumor efficacy of the NPs was evaluated in HT-29 tumor-bearing mice. RESULTS: The nanoparticles were formed at small size (~114 nm) and narrow distribution. The combination of PTX and DHA in the DHA-PEG-PTX nanosystems (PD@PPD) showed remarkably increased apoptosis in colorectal adenocarcinoma HT-29 cells, as compared to free drug treatment. More importantly, the PD@PPD nanoparticles exhibited significantly higher accumulation in the tumor site owing to the enhanced permeability and retention (EPR) effect, effectively restrained the tumor growth in vivo at low-dose of PTX while reducing the systemic toxicity. CONCLUSIONS: The combination of PTX and DHA in a PEG-conjugated dual-drug co-delivery system can minimize the severe side effect associated with the high-dose of PTX while enhancing the antitumor efficacy.