title: Paper bioassay based on ceria nanoparticles as colorimetric probes.
abstract: We report the first use of redox nanoparticles of cerium oxide as colorimetric probes in bioanalysis. The method is based on changes in the physicochemical properties of ceria nanoparticles, used here as chromogenic indicators, in response to the analyte. We show that these particles can be fully integrated in a paper-based bioassay. To construct the sensor, ceria nanoparticles and glucose oxidase were coimmobilized onto filter paper using a silanization procedure. In the presence of glucose, the enzymatically generated hydrogen peroxide induces a visual color change of the ceria nanoparticles immobilized onto the bioactive sensing paper, from white-yellowish to dark orange, in a concentration-dependent manner. A detection limit of 0.5 mM glucose with a linear range up to 100 mM and a reproducibility of 4.3% for n = 11 ceria paper strips were obtained. The assay is fully reversible and can be reused for at least 10 consecutive measurement cycles, without significant loss of activity. Another unique feature is that it does not require external reagents, as all the sensing components are fixed onto the paper platform. The bioassay can be stored for at least 79 days at room temperature while maintaining the same analytical performance. An example of analytical application was demonstrated for the detection of glucose in human serum. The results demonstrate the potential of this type of nanoparticles as novel components in the development of robust colorimetric bioassays.
authors.affiliation: Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, New York 13699-5810, USA.
authors.forename: Maryna
authors.initials: M
authors.lastname: Ornatska
authors.forename: Erica
authors.initials: E
authors.lastname: Sharpe
authors.forename: Daniel
authors.initials: D
authors.lastname: Andreescu
authors.forename: Silvana
authors.initials: S
authors.lastname: Andreescu
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D001786:Blood Glucose / Q000032:analysis*; D002563:Cerium / Q000737:chemistry*; D003124:Colorimetry / Q000379:methods*; D005949:Glucose Oxidase / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D013696:Temperature
chemical_list: D001786:Blood Glucose; D002563:Cerium; C030583:ceric oxide; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase