Enhancing electron transfer of a semiconducting polymer for type I photodynamic and photothermal synergistic therapy.

Tumor hypoxia is responsible for the reduced therapeutic efficacy of type II photodynamic therapy (PDT) because of the dependence of cellular oxygen during 1O2 generation. Type I PDT may be a better strategy to overcome the disadvantages of hypoxia for enhanced theranostics. Herein, a new semiconducting polymer PDPP was synthesized and encapsulated with hydrophilic PEG-PDPA to enhance the electron transfer for type I PDT. PDPP NPs show a high superoxide radical generation ability with DHR123 as a probe. In vitro MTT assay indicates PDPP NPs with considerably high phototoxicity on human cervical cancer cells (HeLa) with a low half-maximal inhibitory concentration (IC50) of 6.1 µg/ml. Furthermore, an in vivo study demonstrates that PDPP NPs can lead to complete tumor suppression with the help of laser, compared with the control and dark groups. The biosafety is confirmed by the H&E analysis of the normal tissues (the heart, liver, spleen, lungs, and kidney). The results provide a strategy to design nanosystems for type I PDT and PTT synergistic therapy.

Research on SVR Water Quality Prediction Model Based on Improved Sparrow Search Algorithm.

Multiparameter water quality trend prediction technique is one of the important tools for water environment management and regulation. This study proposes a new water quality prediction model with better prediction performance, which is combined with improved sparrow search algorithm (ISSA) and support vector regression (SVR) machine. For the problems of low population diversity and easily falling into local optimum of sparrow search algorithm (SSA), ISSA is proposed to increase the initial population diversity by introducing Skew-Tent mapping and to help the algorithm jump out of local optimum by using the adaptive elimination mechanism. The optimal values of the penalty factor C and kernel function parameter g of the SVR model are selected using ISSA to make the model have better prediction accuracy and generalization performance. The performance of the ISSA-SVR water quality prediction model is compared with BP neural network, SVR model, and other hybrid models by conducting water quality prediction experiments with actual breeding-water quality data. The experimental results showed that the prediction accuracy of the ISSA-SVR model was significantly higher than that of other models, reaching 99.2%; the mean square deviation (MSE) was 0.013, which was 79.37% lower than that of the SVR model and 75% lower than that of SSA-SVR model, and the coefficient of determination (R 2) was 0.98, which was 5.38% higher than that of the SVR model and 7.57% higher than that of the SSA-SVR model, indicating that the ISSA-SVR water quality prediction model has some engineering application value in the field of water body management.

An Alternating Copolymer Derived from Indolo[3,2-b]carbazole and 4,7-Di(thieno[3,2-b]thien-2-yl)-2,1,3-benzothiadiazole for Photovoltaic Cells.

An alternating narrow bandgap conjugated copolymer (PICZ-DTBT, E(g) = 1.83 eV) derived from 5,11-di(9-heptadecanyl)indolo[3,2-b]carbazole and 4,7-di(thieno[3,2-b]thien-2-yl)-2,1,3-benzothiadiazole (DTBT), was prepared by the palladium-catalyzed Suzuki coupling reaction. The resultant polymer absorbs light from 350-690 nm, exhibits two absorbance peaks at around 420 and 570 nm and has good solution processibility and thermal stability. The highest occupied molecular orbital (HOMO) energy level and lowest unoccupied molecular orbital (LUMO) level of the copolymer determined by cyclic voltammetry were about -5.18 and -3.35 eV, respectively. Prototype bulk heterojunction photovoltaic cells from solid-state composite films based on PICZ-DTBT and [6,6]-phenyl-C(71) butyric acid methyl ester (PC(71) BM), show power conversion efficiencies up to 2.4% under 80 mW · cm(-2) illumination (AM1.5) with an open-circuit voltage of V(oc) = 0.75 V, a short current density of J(sc) = 6.02 mA · cm(-2) , and a fill factor of 42%. This indicates that the copolymer PICZ-DTBT is a viable electron donor material for polymeric solar cells.