Abstract: A novel method is disclosed wherein polymerized crystalline colloidal array (PCCA) chemical sensing materials are used to detect the presence of certain chemical species in high ionic strength solutions, such as bodily fluids. The PCCA sensors consist of a mesoscopically periodic array of colloidal particles polymerized into a hydrogel. The array of colloidal particles diffracts light in the visible spectral region due to the periodic spacing of the particles. The PCCA materials also contain molecular recognition components that bind to the chemical species being detected. The binding or the chelation of the chemical species of interest results in a Donnan potential that swells the hydrogel and in turn red shifts the diffracted light proportionately to the concentration of the chemical species. However, no significant red shift response may occur for PCCA chemical sensors in high ionic strength solutions containing chemical species of interest.

Abstract: A novel method is disclosed wherein polymerized crystalline colloidal array (PCCA) chemical sensing materials are used to detect the presence of certain chemical species in high ionic strength solutions, such as bodily fluids. The PCCA sensors consist of a mesoscopically periodic array of colloidal particles polymerized into a hydrogel. The array of colloidal particles diffracts light in the visible spectral region due to the periodic spacing of the particles. The PCCA materials also contain molecular recognition components that bind to the chemical species being detected. The binding or the chelation of the chemical species of interest results in a Donnan potential that swells the hydrogel and in turn red shifts the diffracted light proportionately to the concentration of the chemical species. However, no significant red shift response may occur for PCCA chemical sensors in high ionic strength solutions containing chemical species of interest.

Abstract: A novel colorimetric reagent is disclosed which can be used to sense a wide variety of analytes. The novel colorimetric reagent of the present invention is based in part on sensor devices composed of a crystalline colloidal array (CCA) polymerized in a hydrogel, in that the colorimetric reagent is obtained by preparing fragments from the polymerized crystalline colloidal array (PCCA) which are dispersed, for example, in a medium, such a solvent, or in the atmosphere. The hydrogels are characterized as being capable of shrinking and swelling in response to specific stimuli applied thereto. As the hydrogels shrink or swell, the lattice structure of the CCA embedded therein changes, thereby changing the wavelength of light diffracted by the CCA. When the PCCA fragments are in a dispersion in a medium, the diffraction from the dispersion is used to determine the concentration of analyte. The diffraction of the dispersed fragments results in essentially a powder pattern for the diffraction.