Human serum albumin nanoparticles loaded with phthalocyanine dyes for potential use in photodynamic therapy of atherosclerotic plaques

Diseases caused by obstruction or rupture of vulnerable plaques in the arterial walls such as cardiovascular infarction or stroke are the leading cause of death in the world. In the present work, we developed human serum albuminnanoparticles loaded by physisorption with zinc phthalocyanine, TT1, mainly used for industrial application as near-infrared photosensitizer and compared these to HSA NPsloaded with the well-known silicone phthalocyanine (Pc4). The use of NIR light allows for better tissue penetration, while the use of nanoparticles permitshigh local concentrations. The particles were characterized and tested for toxicity and stability as well as for their potential use as a contrast agent and NIR photosensitizer for photodynamic therapy in cardiovascular disease. We focused on the distribution of the nanoparticles in RAW264.7macrophage cells and atherosclerotic mice. The nanoparticles had an average size of 120 nm according todynamic light scattering, good loading capacity for zinc phthalocyanine,and satisfying stability in 50% (v/v) fetal bovine serum for 8 hours and in an aqueous environment at 4°C for 4–6 weeks. Under light irradiation we found a high production of singlet oxygen and the products showed no dark toxicity in vitro with macrophages(the target cells in vulnerable plaques),but at a low μg/mL nanoparticleconcentration killed efficiently the macrophagesupon LED illumination. Injection of the contrast agentin atherosclerotic mice led to a visible fluorescence signal of zinc phthalocyaninein the atherosclerotic plaque at 30 minutes and in the lungs with afast clearance of the nanoparticles. Zinc phthalocyanine loaded human serum albumin nanoparticles present an interesting candidate for the visualization and potentially photodynamictreatment of macrophages in atherosclerotic plaquesThe research leading to these results has received funding from FP7-NMP CosmoPHOS-Nano under grant agreement No. 310337. Additional funding was received by the Spanish groups from MINECO (CTQ2017-85393-P) and ERA-NET/MINECO EuroNanoMed2017-191 / PCIN-2017-04

New cyclopentadithiophene (CDT) linked porphyrin donors with different end-capping acceptors for efficient small molecule organic solar cells

The synthesis of two new A-π-D-π-A molecules bearing a Zn-porphyrin core donor linked through cyclopenta[2,1-b:3,4- b’]dithiophene bridges to the electron-acceptor rhodanine (SA1) or dicyanovinylene (SA2) groups is described. The optical and electrochemical properties of these compounds are investigated. The horizontal conjugation of cyclopentadithiophene between the porphyrin core and the end-capping acceptor not only effectively increases the light harvesting between the Soret and Q bands of the porphyrin unit, but also optimizes the molecular packing through linear -conjugated backbones. Compounds SA1 and SA2 are employed as donors along with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an acceptor in organic bulk heterojunction organic solar cells. After optimizing the processing of the active layer (a solvent additive and subsequent solvent vapor annealing), overall power conversion efficiencies of 6.94% and 8.19% (with low energy loss of 0.55 eV) are obtained for the organic solar cells. The use of a solvent additive and subsequent solvent vapor annealing provide enhanced nanoscale morphology and the bi-continuous interpenetrating networks in the active layer required for efficient exciton dissociation into free charge carriers and their subsequent transportation towards electrodes. This change let to higher PCE values when compared to devices based on as-cast active layers

Use of Thienylenevinylene and Ethynyl Molecular Bridges in Organic Dyes for Dye-Sensitized Solar Cells: Implizations for Device Performance

The synthesis, full characterization, and use of a series of organic dyes with thienylenevinylene and ethynyl bridges as light-harvesting chromophores in TiO2-based photoelectrochemical dye-sensitized solar cells are described. A maximum light-to-energy conversion efficiency of η=5.47 % under standard conditions is obtained for the organic dye denoted as FL16, which consists of an N,N-bis(4-hexyloxyphenyl)aniline donor moiety, an ethynylthieno[3,2-b]thiophene π bridge, and a 2-cyanoacrylic acid acceptor group. The device properties are investigated by charge extraction and transient photovoltage measuremen

High Photo-Current in Solution Processed Organic Solar Cells Based on Porphyrin Core A-π-D-π-A as Electron Donor Material

Two new conjugated acceptor-donor-acceptor (A-p-D-p-A) molecules with a porphyrin core linked by ethynylene bridges to two thiophene (1a) or thienylenevinylenethiophene (1b) units and both capped by N-ethylrhodanine have been synthesized. These compounds were used as the main electron donor moieties for bulk heterojunction small molecule organic solar cells (BHJ-SMOSC). The optimized devices, with PC71BM as the main electron acceptor molecule, show remarkable short circuit currents, up to 13.2 mA/cm2, an open circuit voltage of around 0.85 V, and power conversion efficiencies up to 4.3% under 100 W/cm2. The External Quantum Efficiency (EQE), Atomic Force Microscopy (AFM), hole mobility, Photo-Induced Charge Extraction (PICE) and Photo-Induced Transient Photo-Voltage (PIT-PV) were analyzed in devices based on 1a and 1b in order to account for differences in the final performance of the two molecules. The PIT-PV decays showed slower recombination kinetics for devices fabricated with 1b. Moreover, the EQE was greater for 1b and this is ascribed to the better nanomorphology, which allows better charge collection before carrier recombination takes place