Effects of carotenoids on the absorption and fluorescence spectral properties and fluorescence quenching of Chlorophyll a

Mimicking Thylakoid Membrane with Chlorophyll/TiO2/Lipid Co-Assembly for Light-Harvesting and Oxygen Releasing

There is a growing interest in the design and construction of artificial photosythetic materials for solar energy utilization and conversion. Inspired by the structure of thylakoid membrane, we present here a hybrid construct for light-harvesting and oxygen releasing. Our design conjugates chlorophyll to TiO₂ in a native-like membrane environment. The natural bilayer structure of lipids is utilized to localize the amphiphilic chlorophyll a and hydrophobic tetrabutyl titanate TBOT in the liposomal membrane during hydration process. The coassembled structure, which mimics the essential organization of the thylakoid membrane, is characterized using a combination of field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometer (EDS), Ramam spectra, pressure (π)-area (Α) isotherms, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) analysis. Our results demonstrate successful insertation of chlorophyll a in the membrane and confirm the in situ formation of TiO₂ nanoshell confined at the lipid bilayer/water interface. We further show that the hybrid liposomes exhibit unambiguous photoactivity in visible light-harvesting and oxygen release, likely resulting from a larger specific surface area of the TiO₂ shell, an efficient interfacial conjugation of the chlorophyll molecules with the thin TiO₂ layer. The density functional theory (DFT) calculations were in accordance with the eletron injection processes.We expect that the present work will open a new insight into interfacial recombination between light-harvesting pigments and their sensitized photocatalysis, and develop a new kind of artificial photosynthetic materials with zero-cost of environmental degradation and high efficiency for the photocatalytic O₂ production.

An investigation of copper chlorophyllin solution for low-cost optical devices calibration in chlorophyll measurement

Chlorophylls and turbidity are related parameters deemed important in predicting water quality, especially in the freshwater fisheries sector. In other hand, chlorophyll contents in vegetation are often used as a measure for estimating plant health. To ensure the chlorophyll content, appropriate analysis techniques are needed, which include, yet not limited to, dimethylsulfoxide (DMSO), acetone extraction analysis, and measuring turbidity using expensive equipment. Measurements using these methods are still not reliable, especially for smallholders. In addition, calibration of a digital camera for these purposes requires several efforts of preparing a series of chemical analyses and the qualities of newly developed cameras have increased. Thus, calibration needs to be taken into account for improving the accuracy in estimating chlorophyll contents. This study posits fundamental findings germane to the potential use of chlorophyllin for calibrating the optimal instrument, like consumer-grade cameras. Sodium copper chlorophyllin is commonly used as food additive and ingredients, and medical treatments. However, we can gain another benefit of chlorophyllin, particularly for developing low-cost optical instruments for estimating chlorophyll content through hydro-color-based with promising accuracy.