Low band gap D-A conjugated PNs consisting of 2-ethylhexyl cyclopentadithiophene co-polymerized with 2,1,3-benzothiadiazole (for nano-PCPDTBT) or 2,1,3-benzoselenadiazole (for nano-PCPDTBSe) have been developed. The PNs are stable in aqueous media and showed no significant toxicity up to 1 mg · mL(-1) . Upon exposure to 808 nm light, the PNs generated temperatures above 50 °C. Photothermal ablation studies of the PNs with RKO and HCT116 colorectal cancer cells were performed. At concentrations above 100 µg · mL(-1) for nano-PCPDTBSe, cell viability was less than 20%, while at concentrations above 62 µg · mL(-1) for nano-PCPDTBT, cell viability was less than 10%. The results of this work demonstrate that low band gap D-A conjugated polymers 1) can be formed into nanoparticles that are stable in aqueous media; 2) are non-toxic until stimulated by IR light and 3) have a high photothermal efficiency.

Ag NP are effective photothermal agents. A secondary benefit is the differential response of breast cancer cells to Ag NP-induced hyperthermia, due to increased intracellular silver content, compared to non-tumorigenic breast epithelial cells.

The synthesis and characterization of a soluble high molecular weight copolymer based on 4,8-bis(1-pentylhexyloxy)benzo[1,2-b:4,5-b']dithiophene and 2,1,3-benzoxadiazole is presented. High efficiency organic photovoltaic (OPV) devices comprised of this polymer and phenyl-C(71) -butyric acid methyl ester (PC(71) BM) were fabricated by additive processing with 1-chloronapthalene (CN). When the active layer is cast from pristine chlorobenzene (CB), power conversion efficiencies (PCEs) average 1.41%. Our best condition-using 2% chloronapthalene as a solvent additive in CB-results in an average PCE of 5.65%, with a champion efficiency of 6.05%.

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Donor-acceptor conjugated polymer nanoparticles and nanofibers, based on Poly[4,4-bis(2-ethylhexyl)-cyclopenta[2,1-b;3,4-b']dithiophene-2,6-diyl-alt22,1,3-benzoselenadiazole-4,7-diyl] (PCPDTBSe), were synthesized using Pluronic F127 as a template. The nanomaterials were compared to previously reported PCPDTBSe nanoparticles, which were synthesized without the use of a template. Our goal was to improve on the aqueous stability and photothermal heating efficiency of the previously synthesized PCPDTBSe nanoparticles by decreasing their size and coating them with a biocompatible surfactant. The pluronic wrapped PCPDTBSe (PW-PCPDTBSe) nanoparticles (40-60 nm) showed excellent aqueous stability compared to the PW-PCPDTBSe nanofibers (d 5 20-60 nm, l 5 200-1000 nm) and previously synthesized PCPDTBSe nanoparticles (150 nm). Under stimulation from 800 nm near infrared light (3 W, 1 min), the PW-PCPDTBSe nanoparticles showed greater heat generation (DT 5 47 C) compared to bare PCPDTBSe nanoparticles and PW-PCPDTBSe nanofibers (DT 5 35 C for both). Cytotoxicity studies determined that both the PW-PCPDTBSe nanoparticles and PW-PCPDTBSe nanofibers displayed no significant toxicity toward either noncancerous small intestinal cells (FHs 74 Int) or colorectal cancer cells (CT26). Photothermal ablation studies confirmed that both the PW-PCPDTBSe nanoparticles and the PW-PCPDTBSe nanofibers can be used as localized photothermal agents to eradicate colorectal cancer cells due to their excellent ablation efficiency (>95% cell death at 15 mg/mL concentration).

The photothermal efficiency of two similar organic nanomaterials, poly(3,4-ethylenedioxythiophene):poly(4-styrene-sulfonate) (PEDOT:PSS) nanoparticles and poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes, are compared. The PEDOT:PSS nanoparticles ranged from 100-200 nm in diameter, while the PEDOT nanotubes ranged from 200-400 nm in diameter and 4-10 microm in length. By changing the aspect ratio of the PEDOT nanomaterials from a spherical to a tubular shape, interesting differences in the optical and electronic properties of the materials were realized. Because of this, the PEDOT nanotubes were shown to generate on average approximately to 10 degrees C better internal heating for similar concentrations compared to the PEDOT:PSS nanoparticles. Cytotoxicity studies of both nanomaterials showed no significant toxicity towards RKO or HCT116 colorectal cancer cells in the absence of NIR light. The NIR-mediated photothermal efficiency of the PEDOT:PSS nanoparticles and the PEDOT nanotubes were compared in-vitro. A cell viability assay was performed and at the highest concentration (0.1 mg/mL) of nanomaterial, cell survival was close to 20% for the PEDOT:PSS nanoparticles with both RKO and HCT116 cells. Consequently, cell survival for the PEDOT nanotubes was less than 5% for both RKO and HCT116 cells. An in-vitro three dimensional tumor model was assembled using collagen gel tissue phantoms. The depth of heat penetration from the PEDOT nanotubes into the tissue phantoms, along with cell viability of RKO and HCT116 cells was determined and quantified.

The results of this study support the premise that carbon nanotubes may be effectively utilised as highly localised photothermal agents with the potential for translation into the clinical treatment of bacterial infections of soft tissue.

Airbrush is a promising tool for large scale organic thin film deposition in photovoltaic devices fabrication. This paper reports a detailed study on solar cell performance using airbrush spray deposition for active layer composed with recently developed low band gap donor material poly[4,8-bis(1-pentylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-2,1,3-benzoxadiazole-4,7-diyl and [6,6]-phenyl-C61-butyric acid methyl ester. The effect of carrier solvent and substrate temperature on film morphology are studied; a formula in 1,2-dichlorobenzene sprayed at a substrate temperature of 80 °C is found to be the optimum condition that produces a peak power conversion efficiency of 5.8%.