To satisfy the dual requirements of the fluent transportation in blood and the affinity to the target tissues of vascular diseases, hypocrellin derivatives with optimized amphiphilicity are expected. In this work, 3-amino-1-propanesulfonic acid and 4-amino-1-butanesulfonic acid substituted hypocrellin B, named compounds 1 and 2, were designed, synthesized in high yields and characterized. Besides greatly strengthened red absorption, the maximum solubility of compound 2 in phosphate buffered saline (PBS) is 4.2 mg/mL which is just enough to prepare an aqueous solution for intravenous injection in clinically acceptable concentration, while the partition coefficient between n-octanol and PBS, 5.6, benefits the cell-uptake and biological activity as well. Furthermore, EPR measurements reveal that the photosensitization activities of the two compounds to generate semiquinone anion radicals, superoxide anion radicals and singlet oxygen are a little bit higher than those of taurine substituted hypocrellin B (THB), but the photodynamic activities to human lung cancer A549 cells are several times that of THB, mainly due to increases in lipophilicity and cell-uptake.
LIU XinXIE JieZHANG LuYongCHEN HongXiaGUYingZHAO JingQuan
Different paste has been used for preparing porous TiO2 thin film by screen-printing technique, the main component of it comes from commercial TiO2 P25 power. The dye-sensitized solar cell based on this TiO2 thin film without further chemical treatments exhibits high overall conversion efficiency of 5.81%―6.70%, even with low TiO2 content and thin film thickness. The experimental repeatability is nice and the properties of the films are uniform.
Nanocrystalline TiO2 thin film electrodes have been prepared from mixed pastes of tetrabutyl titanate and nanocrystalline TiO2 particles by common pressure hydro- thermal method at low temperature. The tetrabutyl titanate was hydrolyzed and crystallized into anatase TiO2 to inter- connect nanocrystalline TiO2 particles and adhere them to conductive substrates, obtaining highly porous and me- chanically stable TiO2 nanocrystalline film. The conversion efficiencies of the dye-sensitized solar cells based on prepared electrodes on conductive glass substrates and flexible sub- strates were 4.8% and 1.9% under illumination of 100 mW/cm2, respectively.
LI ChengyuLIN YuanLI XuepingWANG ZhengpingMA YutaoZHOU XiaowenFENG ShujingXIAO Xurui
Nanocrystalline TiO2 thin films were successfully prepared by a new “water-cooked” method on both conductive glass substrates and flexible substrates at low temperature. Dye-sensitized solar cells based on these films have exhibited high overall light-to-electricity conversion efficiencies of 4.67 % and 1.94 % on conductive glass substrate and flexible substrate, respectively, under the illumination at 100 mW/cm2.
H+ concentration induced-monomerization or trimerization of photosystem I (PSI) in cyanobacteria has never been directly observed. In this work, taking characteristic spectra for the trimers and monomers as the indicators, it was experimentally demonstrated that H+ could induce the oligomeric changes of PSI reaction centers in the intact Spirulina platensis cells and also in the isolated thylakoid membrane complexes. Especially, the higher concentration of H+ would induce the monomerization while the lower the trimerization, suggesting the electrostatic interaction should be mainly responsible for changes in the oligomeric state of PSI in Spirulina platensis.
