Microcapsule-Based Signal Amplification Method for Biomolecules

The direct signal amplification of target molecules could be an effective means of increasing the sensitivity and reducing the size of biosensors. The purpose of this study was to propose a novel signal amplification method suitable for the detection of biomolecules using microcapsules that can quickly respond to concentration variation. This microcapsule-based amplification method consists of two elements—microcapsules and a well-array. The microcapsules consist of (i) an inner shell fabricated through layer-by-layer assembly, (ii) a lipid bilayer, and (iii) loaded target molecules. In this method, the inner surface of the well-array was modified using TiO2 as a photocatalyst. The diameter and thickness of the fabricated micro-capsules for biomarker loading were shown to be 2.7 μm and 78 nm, respectively. An ultraviolet (UV) irradiation time of 5 min was needed when the change in optical density reached 90% saturation of the optical density change. Dye molecules were incorporated into the microcapsules and were subsequently released, and the concentration of the released solution changed in proportion with the encapsulated dye concentration. This demonstrates the proof of concept for this novel signal amplification method based on microcapsules.

Electrochromic Property of Sputtered Amorphous NiO Films

Nickel oxide (NiO) thin films were deposited on ITO/glass substrates by radio frequency magnetron sputtering. The electrochromic property of NiO films was investigated using cyclic voltammograms (CV), performed on NiO films immersed in an electrolyte of 1 M LiClO4in propylene carbonate (PC). Optical, electrochemical and structural properties of the films, as a function of coloration–bleaching cycle, were characterized using an UV-Vis-NIR spectrophotometer, cyclic voltammetry (CV), X-ray diffraction(XRD) and a field emission scanning electron microscope (FE-SEM). The optimal electrochromic NiO film, with a thickness of 180 nm, exhibits a maximum transmittance variation (ΔT%) of 53.97 %, an optical density change (ΔOD) of 0.66, an intercalation charge (Q) of 14.65 mC/cm2, and a coloration efficiency (η) of 44.85 cm2/C between the colored and bleached states at a wavelength (λ) of 550 nm.

Isotopic Effect on the Kinetic of Thermal Denaturation of Ceruloplasmin

The kinetics of thermal denaturation of ceruloplasmin in water and in water with different percentage of D20 in the temperature range 25 - 85 °C, following the optical density change of the 610 nm charge transfer band of the protein has been investigated. A temperature Tt ≃ 65 °C above which an irreversible denaturation process of the protein active site takes place has been found. The kinetics of the denaturation process of the protein are fitted by two first order reactions, which have been assigned to a different thermal denaturation behaviour of the two Cu2+ type I sites existing in the protein. Addition of D2O to the protein solution affects the two kinetics in a different way, i.e. the rate of one of them is increased whilst that of the other is decreased. The different effect of D2O on the kinetics of disruption of the two copper sites is discussed in terms of different location and degree of hydrophobicity of the two Cu2+ type I sites.