Protein hydrogel-based microchips are being developed for high-throughput evaluation of the concentrations and activities of various proteins. To shorten the time of analysis, the reaction-diffusion kinetics on gel microchips should be accelerated. Here we present the results of the experimental and theoretical analysis of the reaction-diffusion kinetics enforced by mixing with peristaltic pump. The experiments were carried out on gel-based protein microchips with immobilized antibodies under the conditions utilized for on-chip immunoassay. The dependence of fluorescence signals at saturation and corresponding saturation times on the concentrations of immobilized antibodies and antigen in solution proved to be in good agreement with theoretical predictions. It is shown that the enhancement of transport with peristaltic pump results in more than five-fold acceleration of binding kinetics. Our results suggest useful criteria for the optimal conditions for assays on gel microchips to balance high sensitivity and rapid fluorescence saturation kinetics.

Semiempirical quantum chemical simulations have been undertaken to obtain the self-consistent atomic and electronic structure of the two basic electron defects in MgO crystals: F+ and F centres (one and two electrons trapped by an O vacancy, Va. The calculated absorption and luminescence energies agree well with the experimental data; the excited states of both defects are found to be essentially delocalised over nearest-neighbour cations. The activation energy for diffusion is found to increase monotonically in a series Va → F+ → F centre (2.50eV, 2.72 eV and 3.13 eV, respectively).
Materials Science and Engineering B Volume 37, Issues 1-3, February 1996, Pages 212-214

Actin filaments are certainly believed to function as an intracellular signalling system; however, this is not confirmed by direct evidence. We used a two-layer actomyosin gel with a concen tration gradient of the troponin-tropomyosin complex (TT-complex, Ca2+-sensitive system) between the two layers. To prepare one layer of the system, natural actomyosin (nАМ) rich in TT-complex was used. To prepare the second layer, we used desensitized actomyosin (dAM) without the complex. All experimental studies were made in medium with a low ionic strength. Two phenomena were ob served: (1) dAM blocks Ca2+-sensitivity of nAM when the dAM weight portion in the system (as well as in mixed nAM+dAM suspension) reaches 40% and more; further increase of the dAM portion does not affect the Ca2+-sensitivity; (2) it was electrophoretically shown that a rapid diffusion of the TT-complex from nAM gel into the dAM gel took place. The apparent diffusion coefficient for the TT-complex in dAM gel is about (1-4)·10-4 cm2/sec, i.e. three orders higher than the same values for pro tein diffusion in water.
32: 167-178