We will develop novel, simple, inexpensive clinical chemistry sensing materials which can be used as visual color test strips to sensitively and selectively report on the concentration and identity of important analytes such as Pb2+, K+, Hg2+, pH, Ca2+, etc. We will develop inexpensive clinical test strips which can be immersed in bodily fluids to accurately determine analytes at the patient bedside. We will also develop arrays of these chemical sensing materials which will be attached to fiber optic bundles to be used as multichannel optrodes to simultaneously monitor numerous analytes. These sensing materials are based on the intelligent polymerized crystalline colloidal array technology we recently developed. This innovative sensing motif utilizes a mesoscopically periodic array of colloidal particles polymerized into an acrylamide hydrogel. This array diffracts light in the visible spectral region due to the periodic array of colloidal particles. This material also contains chelating agents tailored for the analytes of interest. When an analyte binds, its charge is immobilized within the acrylamide hydrogel. The resulting Donnan potential causes an osmotic pressure, which swells the hydrogel array in proportion to the concentration of analyte bound. This results in shifts in the diffracted wavelength and in the perceived color changes. The change in the wavelength diffracted reports on the identity and concentration of the target analyte. This motif is highly flexible and can be modified to sense a broad variety and concentration of biologically relevant analytes.
