Abstract: The invention relates to novel methods and compositions for the detection of analytes using the nuclear reorganization energy, &lgr;, of an electron transfer process.

Abstract: An apparatus and method of use for assaying cellular motility in response to a concentration gradient of a chemotactic agent. Generally, the apparatus includes a chamber having a region for receiving a biological sample containing cells of interest and, spaced apart from such region, another region for receiving a chemotactic agent. Between these regions, a concentration gradient of chemotactic agent is established. The apparatus further includes an optical system for detecting and mapping the positions of individual cells responsive to such concentration gradient. Means for processing and analyzing the collected data are also provided. Motility determinations may be made on purified or unpurified samples. Single-site assay devices and multi-site, high-throughput assay devices are disclosed.

Abstract: Receptor molecules are anchored on a solid or fluid flat substrate, these being able to selectively bind other atoms or molecules. The substrate surface is then ellipsometrically measured in that the change of the state of polarization, undergone by the linearly polarized light with the reflection on the substrate, is acquired. Subsequently, the substrate with the receptor molecules anchored thereon, for coupling the atoms or molecules to be determined, are exposed to the latter, after which an ellipsometrical measurement is again effected. The changes in the state of polarization are compared to values evaluated by way of reference samples, after which a qualitative and quantitative determination of the coupled atoms or molecules is effected.