Dye-sensitised Photocatalyst for Photocatalytic Whole Water Splitting to Produce Hydrogen in a Twin Photoreactor

Organic dye-sensitised SrTiO3:Rh and WO3 were served as H2 catalysts and O2 catalysts in a Z-scheme system to conduct photocatalytic pure water splitting. To enhance the light absorption capacity, the composites of organic dye (N3, N719, Z907, black dye, C101, and K19) and SrTiO3:Rh were synthesised via physical adsorption and then verified by the performance of photocatalytic hydrogen evolution. Among these dyes, N3-SrTiO3:Rh revealed visible light absorption and exhibited the best photocatalytic activity. Therefore, N3 dye was adopted, and silane coupling agents were used to form chemical bonding with SrTiO3:Rh. Furthermore, the photocatalytic pure water splitting of N3-SrTiO3:Rh was investigated in a single reactor, and a twin photoreactor with Fe2+ and Fe3+ ions served as the electron mediators, respectively. The highest quantum efficiency can reach 0.0259% in a twin reactor when compared with the single reactor (0.0052%) because of the improvement in the light absorption from N3 and inhibition of the backward reaction of water splitting. Consequently, organic dye-sensitised photocatalysts are highly effective and eco-friendly in conducting photocatalytic pure water splitting.

Electron Mediation and Photocurrent Enhancement in Dunalliela salina Driven Bio-Photo Electrochemical Cells

In recent years, finding alternatives for fossil fuels has become a major concern. One promising solution is microorganism-based bio-photo electrochemical cells (BPECs) that utilize photosynthetic solar energy conversion as an energy source while absorbing CO2 from the atmosphere. It was previously reported that in cyanobacterial-based BPECs, the major endogenous electron mediator that can transfer electrons from the thylakoid membrane photosynthetic complexes and external anodes is NADPH. However, the question of whether the same electron transfer mechanism is also valid for live eukaryotic microalgae, in which NADPH must cross both the chloroplast outer membrane and the cell wall to be secreted from the cell has remained elusive. In this work, we show that NADPH is also the major endogenous electron mediator in the microalgae Dunalliela salina (Ds). We show that the ability of Ds to tolerate high salinity enables the production of a photocurrent that is 5–6 times greater than previously reported for freshwater cyanobacterial-based BPECs in the presence or absence of exogenous electron mediators. Additionally, we show that the electron mediator Vitamin B1 can also function as an electron mediator enhancing photocurrent production. Finally, we show that the addition of both FeCN and NADP+ to Ds has a synergistic effect enhancing the photocurrent beyond the effect of adding each mediator separately.

Silver Nanomaterials as Electron Mediators in a Bio-Electronic Tongue Dedicated to the Analysis of Milks. The Role of the Aspect Ratio of Nanoparticles vs. Nanowires

The integration of silver nanomaterials as electron mediators in electrochemical biosensors can be crucial to improve the affinity with biomolecules and the electrochemical response. In this work, two voltammetric bioelectronics tongues (bioET) formed by biosensors based on the combination of enzymes with silver nanoparticles (AgNPs) (bioET-1) or silver nanowires (AgNWs) (bioET-2) have been developed and used to analyze milks. Each array was formed by four biosensors formed by enzymes (glucose oxidase, galactose oxidase, β-galactosidase and a blank), capable to detect compounds usually found in milks. Principal component analysis (PCA) has revealed the ability of both biosensor systems to discriminate between milk samples with different fat contents, but with some differences, attributed to the structure employed in the detection.

Indigofera Tinctoria Leaf Powder As A Promising Additive To Improve Indigo Fermentation Prepared With Sukumo (Composted Polygonum Tinctorium Leaves)

Being insoluble in the oxidize form, indigo dye must be solubilized by reduction for it to penetrate textile. One of the procedures is the reduction by natural bacterial fermentation. Sukumo, composted leaves of Polygonum tinctorium, is a natural source of indigo in Japan. Although sukumo has an intrinsic bacterial seed, the onset of indigo reduction with this material may vary greatly. Certain additives improve indigo fermentation. Here, we studied the effects of Indigofera tinctoria leaf powder (LP) on the initiation of indigo reduction, bacterial community, redox potential (ORP), and dyeing intensity in the initial stages and in aged fermentation fluids prepared with sukumo. I. tinctoria LP markedly decreased ORP at day 1 and stabilised it during early fermentation. These effects could be explained by the phytochemicals present in I. tinctoria LP that act as oxygen scavengers and electron mediators. Using next generation sequencing results, we observed differences in the bacterial community in sukumo fermentation treated with I. tinctoria LP, which was not influenced by the bacterial community in I. tinctoria LP per se. The concomitant decrease in Bacillaceae and increase in Proteinivoraceae at the onset of fermentation and the ratio of facultative to obligate anaerobes are vital to the for initiation and maintenance of indigo reduction. Hence, I. tinctoria LP improved early indigo reduction by decreasing the ORP and hasten the appropriate transitions in the bacterial community in sukumo fermentation.

Translational research of hemoglobin vesicles as a transfusion alternative

: Clinical situations arise in which blood for transfusion becomes scarce or unavailable. Considerable demand for a transfusion alternative persists because of various difficulties posed by blood donation and transfusion systems. Hemoglobin-vesicles (HbV) are artificial oxygen carriers being developed for use as a transfusion alternative. Just as biomembranes of red blood cells (RBCs) do, phospholipid vesicles (liposomes) for Hb encapsulation can protect the human body from toxic effects of molecular Hb. The main HbV component, Hb, is obtained from discarded human donated blood. Therefore, HbV can be categorized as a biologic agent targeting oxygen for peripheral tissues. The purification procedure strictly eliminates the possibility of viral contamination. It also removes all concomitant unstable enzymes present in RBC for utmost safety from infection. The deoxygenated HbVs, which are storable for over years at ambient temperature, can function as an alternative to blood transfusion for resuscitation from hemorrhagic shock and O2 therapeutics. Moreover, a recent study clarified beneficial effects for anti-oxidation and anti-inflammation by carbon monoxide (CO)-bound HbVs. Autoxidation of HbV (HbO2 → metHb + O2-.) is unavoidable after intravenous administration. Co-injection of methylene blue can extract the intraerythrocytic glycolytic electron energy effectively and reduce metHb. Other phenothiazine dyes can also function as electron mediators to improve the functional life span of HbV. This review paper summarizes recent progress of the research and development of HbV, aimed at clinical applications.