The formation of calcium carbonate (CaCO
) nanoparticles (NPs) in the presence of polystyrene sulfonate (PSS) as an additive was examined by time-resolved small-angle X-ray scattering (SAXS) in a ...flow system that mimics experimental conditions used at home facilities where the precipitation can be achieved in a beaker. The experiments were carried out at low concentrations to remain in the dilute regime. A model-independent analysis was performed using the Porod invariant which defines the scale factor, leaving only the distribution of radii as the adjustable parameter. The presence of the PSS additive strongly retards the precipitation of CaCO
NPs. The formation of NPs reaches a state of equilibrium after a few minutes. Here, it is shown that the concentration of precursors at a fixed PSS concentration plays a key role in determining the size of the NPs obtained. A full analysis of the SAXS patterns was carried out using the Hurd-Flower model to account for the weaker intensity decay than the classical Porod behaviour. The temporal evolution of the particle radii was determined. Wide-angle X-ray scattering experiments carried out simultaneously show that the particles formed have the structure of vaterite with growth consistent with the evolution of the Porod invariant.
The formation of calcium carbonate (CaCO3) nanoparticles (NPs) in the presence of polystyrene sulfonate (PSS) as an additive was examined by time‐resolved small‐angle X‐ray scattering (SAXS) in a ...flow system that mimics experimental conditions used at home facilities where the precipitation can be achieved in a beaker. The experiments were carried out at low concentrations to remain in the dilute regime. A model‐independent analysis was performed using the Porod invariant which defines the scale factor, leaving only the distribution of radii as the adjustable parameter. The presence of the PSS additive strongly retards the precipitation of CaCO3 NPs. The formation of NPs reaches a state of equilibrium after a few minutes. Here, it is shown that the concentration of precursors at a fixed PSS concentration plays a key role in determining the size of the NPs obtained. A full analysis of the SAXS patterns was carried out using the Hurd–Flower model to account for the weaker intensity decay than the classical Porod behaviour. The temporal evolution of the particle radii was determined. Wide‐angle X‐ray scattering experiments carried out simultaneously show that the particles formed have the structure of vaterite with growth consistent with the evolution of the Porod invariant.
The kinetics of precipitation of CaCO3 particles in the presence of polystyrene sulfonate was studied by small‐ and wide‐angle X‐ray scattering. Employment of the Porod invariant and the Hurd–Flower model provides essential information on the kinetics.
The future of photodynamic therapy (PDT) as a promising cancer treatment relies on the development of new selective and effective photosensitizers (PS) with improved photophysical and biochemical ...qualities. Herein, we present the synthetic procedure, photophysical properties and photosensitizing effects of novel glycosylated 4,5,6,7‐tetrahydropyrazolo1,5‐apyridine fused chlorin agents featuring either glucose, galactose, or N‐acetyl glucosamine. It is shown that both the proto‐ and Zn2+‐ion forms of the ring‐stabilized glycochlorins exhibit the required photophysical properties in terms of triplet excited states and singlet oxygen generation, the latter more than 50 % in organic solvents such as CHCl3. Employing the rat AY‐27 and human T24 cancer cell models, it was found that these are superior to the corresponding unglycosylated chlorin in biological activity, and moreover, the proto form is 2–3 times superior to the Zn‐stabilized variant. Provisional flow cytometry and cell localization studies of the proto‐form indicate both necrotic and apoptotic biological activity, and that the photosensitizer localizes in the mitochondria, cell membrane and lysosomes. However, the localization into the lysosomes is dominating and increases substantially with time. We anticipate the findings will aid in the development of photosensitizers for targeted cancer PDT.
Sweet as sugar: Herein, we report a structural, photobiological, and photophysical investigation of novel glycosylated chlorins. The cytotoxicity and photodynamic therapy (PDF) effects were studied in rat (AY‐27) and human (T24) cell lines. Additionally, the photophysical properties including excited triplet states were investigated using transient absorption spectroscopy. Results on steady‐state and transient singlet oxygen phosphorescence at 1275 nm are presented.
