Recombinant laccase: II. Medical biosensor.

Langmuir-Blodgett (LB) technology was used to build a high-sensitivity enzyme-based biosensor for medical purposes. Recombinant fungal laccase from Rigidoporous lignosus, as previously described, was used to catalyze a widely used antidepressant in a micromolar range, namely, clomipramine. The topological properties of the laccase thin film were characterized via LB π-A isotherm and AFM (mean roughness 8.22 nm, compressibility coefficient 37.5 m/N). The sensitivity of the biosensor was investigated via UV spectroscopy, and linearity was found in the absorbance peak shift at 400 nm at drug concentration varying up to 20 uM. The enzyme kinetics was subsequently investigated with potentiometric and amperometric measurements, and we found electronic transfer of at least 1 electron, k(s) 0.57 s(-1), diffusion coefficient 3 × 10(-6) cm(2)/s, K(cat) 6825.92 min(-1), K(M) 4.1 uM, K(cat)/K(M) 2.8 × 10(7) mol(-1) s(-1), sensitivity of 440 nA/uM, maximum velocity 1706.48 nA/s, and response time less than 5 s. The amperometric and potentiometric measurements were repeated after a month, confirming the stability of the biosensor.

Langmuir-Blodgett nanotemplate and radiation resistance in protein crystals: state of the art.

A state-of-the-art review of the role of the Langmuir-Blodgett nanotemplate on protein crystal structures is here presented. Crystals grown by nanostructured template appear more radiation resistant than the classical ones, even in the presence of a third-generation highly focused beam at the European Synchrotron Radiation Facility. The electron density maps and the changes in parameters such as total diffractive power, B-factor, and pairwise R-factor have been discussed. Protein crystals, grown by the Langmuir-Blodgett nanotemplate-based method, proved to be more radiation resistant compared to crystals grown by the classical hanging drop method in terms of both global and specific damage.

Oxygen-bound Hell's gate globin I by classical versus LB nanotemplate method.

X-ray atomic structure of recombinant Hell's gate globin I (HGbI) from Methylacidophilum infernorum was calculated from the X-ray diffraction data of two different types of crystals: obtained by classical hanging drop and by LB nanotemplate method under the same crystallization conditions. After the accurate comparison of crystallographic parameters and electron density maps of two structures they appears to be quite similar, while the quality of the crystals grown by LB nanotemplate method was higher then of those grown by classical method. Indeed, the resolution of the LB crystal structure was 1.65 Å, while classical crystals showed only 3.2 Å resolution. Moreover, the reproducibility of this result in the case of LB crystals was much better-nine crystals from 10 gave the same structural results, while only two of 10 classical crystals were appropriate for the X-ray structure resolution.

Matrices for Sensors from Inorganic, Organic, and Biological Nanocomposites.

Matrices and sensors resulting from inorganic, organic and biological nanocomposites are presented in this overview. The term nanocomposite designates a solid combination of a matrix and of nanodimensional phases differing in properties from the matrix due to dissimilarities in structure and chemistry. The nanoocomposites chosen for a wide variety of health and environment sensors consist of Anodic Porous Allumina and P450scc, Carbon nanotubes and Conductive Polymers, Langmuir Blodgett Films of Lipases, Laccases, Cytochromes and Rhodopsins, Three-dimensional Nanoporous Materials and Nucleic Acid Programmable Protein Arrays.