A potentiometric protein sensor built with surface molecular imprinting method

Surface molecular imprinting, as compared to molecular imprinted bulk polymers, has the advantages of higher re-occupation percentage of the reception sites, fast response, integration of sensing element and transducer, etc. In this study, a potentiometric protein sensor was developed based on the surface molecular imprinting technique. Using the self-assembled monolayers of alkanethiol with hydroxyl terminal groups as the matrix material, and target protein molecules as the template, the sensing layer was created on the surface of the gold-coated silicon chip-an electrochemical transducer. Potentiometric measurement demonstrated that the sensor could selectively detect myoglobin or hemoglobin molecules, either with or without the presence of other protein molecules in the same solution.

ARTICLE

Biochemical impact of a soccer match — analysis of oxidative stress and muscle damage markers throughout recovery

Background
Exercise is a prone condition to enhanced oxidative stress and damage and the specific activity pattern of a soccer match may favour additional pro-oxidant redox alterations. To date, no studies have reported the impact of a soccer match on oxidative stress and muscle damage markers.

Aim
To analyse the effect of a competitive soccer match on plasma levels of oxidative stress and muscle damage markers, and to relate these findings with lower limb functional data.

Methods
Blood samples, leg muscle strength, sprint ability and delayed-onset muscle soreness (DOMS) were obtained in 16 soccer players before, at 30 min, 24, 48 and 72 h after a soccer match. Plasma creatine kinase (CK), myoglobin (Mb), malondialdehyde (MDA), sulfhydryl (–SH) groups, total antioxidant status (TAS), uric acid (UA) and blood leukocyte counts were determined.

Results
A soccer match elevated plasma Mb following 30 min and creatine kinase (CK) levels throughout the 72 h-recovery period. MDA increased throughout the recovery period and –SH decreased until 48 h post-match. TAS increased at 30 min and UA increased throughout the 72 h recovery. Blood neutrophils increased at 30 min whereas lymphocytes decreased and returned to baseline from 24 to 72 h. DOMS was higher than baseline until 72 h. Lower limb strength and sprint ability were lower than baseline until 72 h recovery.

Conclusion
The present data suggest that a soccer match increases the levels of oxidative stress and muscle damage throughout the 72 h-recovery period. The extent to which the redox alterations are associated with the recovery of muscle function should be further analysed.

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Toward Quantitative Simulations of Carbon Monoxide Escape Pathways in Myoglobin

Straightforward molecular dynamics trajectories have been computed to explore the diffusion of carbon monoxide through myoglobin. The classical equations of motion were integrated for 2 ns and the resulting pathways analyzed. Two types of runs were examined. Type i: myoglobin and a ligand embedded in a periodic box with 9996 water molecules; the water molecules are rigid but the bonds of the protein are flexible. Type ii:myoglobin with a solvation shell (153 water molecules) in which all bond lengths are fixed. In trajectories of type i, the diffusing ligand visits a significant part of the protein matrix and was not constrained to the proximity of the heme pocket before escaping. The maximum time of the trajectories was 2 ns. It was shorter if the ligand escaped earlier. Two ligands (from a total of 88) escape to the solvent from nonclassical gates (non-E-helix gates). In trajectories of type ii, the overall fluctuations of the protein are smaller and the ligand explores significantly smaller internal space. The escape rate from type ii trajectories (11 of 400) is comparable to type i and is not dramatically different from experiment (1 of 100). Interestingly, the two simulations with comparable rates sampled different pathways. In trajectories of type ii, we observe escapes from the classical gate (His 64) and from the Xe4 cavity. Further studies (that are underway) are required to define the escape pathways and the overall rate.

What is Myoglobin?

Myoglobin is a cytoplasmic hemoprotein that is restricted to cardiomyocytes and oxidative skeletal muscle fibers. Myoglobin is a well-characterized protein and numerous studies have established that it has an essential role in facilitated oxygen transport in striated muscles. Recent strategies, using gene disruption technologies, have produced mice that lack myoglobin. These myoglobin deficient mice have a binary phenotype and a subpopulation of these mutant mice is viable and fertile. Characterization of the viable myoglobin null mice has uncovered a number of molecular and cellular adaptive mechanisms that function to promote oxygen delivery in the mutant striated muscle cell. Moreover, cellular and physiological studies, using the myoglobin deficient mouse model, support the conclusion that the functions of myoglobin include: facilitated oxygen transport, the storage of oxygen and a scavenger of nitric oxide or reactive oxygen species. Collectively, the use of genetic mouse models will further enhance our understanding of myoglobin function in normal and pathological muscle lineages.

Third generation biosensor based on myoglobin-TiO2/MWCNTs modified glassy carbon electrode

TiO2 nanoparticles were homogeneously coated on multi-walled carbon nanotubes by hydrothermal deposition, this nanocomposite may be a promising material for myoglobin immobilization in view of its high biocompatibility and large surface. The glassy carbon electrode modified with Mb-TiO2/MWCNTs films exhibited a pair of well defined, stable and nearly reversible cycle voltammetric peaks. The electron transfer between Mb and electrode surface, Ks of 3.08 s−1, was greatly facilitated in the TiO2/MWCNTs film. The electrocatalytic reductions of hydrogen peroxide were studied, the apparent Michaelis–Menten constant is calculated to be 83.10 μmol/L, which shows a large catalytic activity of Mb in the TiO2/MWCNTs film to H2O2.


ARTICLE

A potentiometric protein sensor built with surface molecular imprinting method

Surface molecular imprinting, as compared to molecular imprinted bulk polymers, has the advantages of higher re-occupation percentage of the reception sites, fast response, integration of sensing element and transducer, etc. In this study, a potentiometric protein sensor was developed based on the surface molecular imprinting technique. Using the self-assembled monolayers of alkanethiol with hydroxyl terminal groups as the matrix material, and target protein molecules as the template, the sensing layer was created on the surface of the gold-coated silicon chip-an electrochemical transducer. Potentiometric measurement demonstrated that the sensor could selectively detect myoglobin or hemoglobin molecules, either with or without the presence of other protein molecules in the same solution.

ARTICLE