Stability Modification of Dye-sensitized Solar Cells by Ruthenium Dyes Embedded on Eggshell Membranes

Dye-sensitized solar cells (DSSCs) have been one of the most promising technologies to convert sunlight into electricity repeatedly based on the mechanism that dyes inject/accept electron into the metal oxides/from redox mediator. Specifically, N719 ([RuL2(NCS)2], L: 4,4'-dicarboxy-2,2'-bipyridine), immobilized on TiO2 through the interaction between its ligands (-COO- and -NCS) and the oxygen on the TiO2 surface, has been used as a conventional DSSC dye with high voltage. Nevertheless, -NCS ligands have been removed from Ru2+ in N719 due to UV irradiation and exchanged with H2O or OH- in electrolyte, resulting in voltage drop. In this work, we developed the first DSSC using the N719-adsorbed Eggshell (ESM)-TiO2 composite to maintain the immobilization of N719 on TiO2 through electrostatic interaction between the protein of ESM and N719. The DSSC using the composite maintained the voltage even after 12 h light irradiation, although the voltage of DSSC without ESM dropped drastically. It means that the ESM contributed to stable photovoltaic performances of DSSCs through the protection of NCS ligands of N719.

Investigating structure-property relationships of biomineralized calcium phosphate compounds as fluorescent quenching-recovery platform

The structure-property relationship between biomineralized calcium phosphate compounds upon a fluorescent quenching-recovery platform and their distinct crystalline structure and surficial functional groups are investigated. A fluorescence-based sensing platform is shown to be viable for the sensing of 8-hydroxy-2-deoxy-guanosine in simulated systems.

Sonochemical synthesis of hydroxyapatite nanoflowers using creatine phosphate disodium salt as an organic phosphorus source and their application in protein adsorption

Hydroxyapatite nanosheets-assembled nanoflowers are sonochemically synthesized using creatine phosphate, which have excellent cytocompatibility and relatively high protein adsorption ability.

A fluorescence-quenching platform based on biomineralized hydroxyapatite from natural seashell and applied to cancer cell detection

As a typical biomineral, hydroxyapatite (HAp) is widely applied in bone implants and other related fields. However, the inherent nature of HAp can potentially be altered through restricting its fabrication conditions. Here, HAp fabricated by a hydrothermal treatment of pieces of natural seashell is demonstrated to have the capability of fluorescence quenching. To the best of the author's knowledge, this is the first time that this new property of HAp has been reported. Consequently, we assembled a fluorescence-quenching platform based on the biomineralized HAp substrate following a hydrothermal treatment and associated with a DNA molecular beacon and applied to cancer cell detection by the transformation from “OFF state” (fluorescence quenching) to “ON state” (fluorescence recovery). Herein, we found that the outer surface of HAp material after hydrothermal biomineralization for 5 days has considerable capability for both fluorescence quenching and recovery. These results may also have implications in the further detection of various targets such as cancer cells with other special surface antigens, significant biological small molecules or disease related microRNA, just by changing the sequence of the nucleic acid beacon according to the corresponding aptamer.

[Properties of modified amperometric biosensors based on methanol dehydrogenase and Methylobacterium nodulans cells]

The properties of amperometric biosensors based on methanol dehydrogenase (MDH), Methylobacterium nodulans cells, and the ferrocene-modified carbon paste electrode were investigated. It was shown that the addition ofhydroxyapatite (HA) to a carbon paste increased the sensitivity and operating stability of MDH biosensors. The linear range of the electrode was 0.0135-0.5 and 0.032-1.5 mM for methanol and formaldehyde, respectively. The detection limit of methanol and formaldehyde was 4.5 and 11.0 microM, respectively. The loss of activity of the electrode within 10 days of storage in the presence of 2.0 mM KCN did not exceed 12%. Cyanide (10 mM) completely inhibited the sensor responses to formaldehyde (1.0 mM), which allowed for the selective determination of methanol in the presence of formaldehyde. The biosensor based on cells exhibited lower stability and sensitivity toward methanol and formaldehyde; the sensitivity coefficients were 980 and 21 nA/mM, respectively.