Биосенсоры на основе термисторов

Калориметрические преобразователи

Интереферометрические

Поляризационная интерферометрия. Other evanescent wave biosensors have been commercialised using waveguides where the propagation constant through the waveguide is changed by the absorption of molecules to the waveguide surface. One such example, Dual Polarisation Interferometry uses a buried waveguide as a reference against which the change in propagation constant is measured. Other configurations such as the Mach-Zehnder have reference arms lithographically defined on a substrate. Higher levels of integration can be achieved using resonator geometries where the resonant frequency of a ring resonator changes when molecules are absorbed.

Dual polarization interferometry (DPI) is an analytical technique that can probe molecular scale layers adsorbed to the surface of a waveguide by using the evanescent wave of a laser beam confined to the waveguide. It is typically used to measure the conformational change in proteins, or other biomolecules, as they function (referred to as the conformation activity relationship).

DPI focuses laser light into two waveguides. One of these functions as the "sensing" waveguide having an exposed surface while the second one functions to maintain a reference beam. A two-dimensional interference pattern is formed in the far field by combining the light passing through the two waveguides. The DPI technique rotates the polarization of the laser, to alternately excite two polarization modes of the waveguides. Measurement of the interferogram for both polarizations allows both the refractive index and the thickness of the adsorbed layer to be calculated. The polarization can be switched rapidly, allowing real-time measurements of chemical reactions taking place on a chip surface in a flow-through system. These measurements can be used to infer conformational information about the molecular interaction staking place, as the molecule size (from the layer thickness) and the fold density (from the RI) change. DPI is typically used to characterise biochemical interactions by quantifying any conformational change at the same time as measuring reaction rates, affinities and thermodynamics.

The technique is quantitative and real-time (10 Hz) with a dimensional resolution of 0.01 nm.

Начаты разработки новых поколений биодатчиков на базе аф­финных взаимодействий (биосродства) типа фермент-ингибитор, антитело-антиген, агонист (антагонист)- клеточный рецептор на основе полупроводниковых устройств-термисторов и пьезоэлектрического эффекта.

Термистор представляет собой полупроводниковый резистор, сопротивление которого изменяется с изменением температуры. Датчик представляет собой термистор, на поверхности которого находятся иммобилизо- ванные клетки или молекулы ферментов или антител. Он с высокой чувствительностью регистрирует изменения температуры, происходящие при протекании биохимических реакций с анализируемыми веществами.

Дата добавления: 2014-01-14