A biosensor for the detection of an analyte such as ascorbic acid is provided. Also provided is a device comprising the biosensor. In addition, methods of detecting analytes such as ascorbic acid in a sample, and methods of a point-of-care diagnosis of eye disease and eye injury are provided.

A self-contained anaerobic environment-generating culture device is provided. The culture device includes a first substrate having opposing inner and outer surfaces, a second substrate having opposing inner and outer surfaces, a growth region disposed between the inner surfaces of the first and second substrates, an effective amount of a substantially dry enzyme component of an enzyme-mediated oxygen depletion system, an effective amount of a substantially dry enzyme substrate component of the enzyme-mediated oxygen depletion system, and a dry, cold-water-soluble gelling agent disposed in the growth region. The enzyme and enzyme substrate components are disposed in coatings in the growth region. The first and second substrates are substantially nontransmissible to gaseous oxygen. Methods of making and using the culture device area also provided.

A biosensor for the detection of an analyte such as ascorbic acid is provided. Also provided is a device comprising the biosensor. In addition, methods of detecting analytes such as ascorbic acid in a sample, and methods of a point-of-care diagnosis of eye disease and eye injury are provided.

Provided are: a method for stabilizing an ascorbic acid oxidase; a method for preserving an ascorbic acid oxidase; and a stabilized composition of an ascorbic acid oxidase. A method for stabilizing an ascorbic acid oxidase and a method for preserving an ascorbic acid oxidase, each of the methods comprising allowing an ascorbic acid oxidase to coexist with nitrous acid or a salt thereof, or a nitrous acid ester in an aqueous medium; and a stabilized composition of an ascorbic acid oxidase, which comprises an ascorbic acid oxidase being allowed to coexist with nitrous acid or a salt thereof, or a nitrous acid ester in an aqueous medium. The method for stabilizing an ascorbic acid oxidase, the method for preserving an ascorbic acid oxidase, and the stabilized composition of an ascorbic acid oxidase according to the present invention are useful for clinical diagnosis and the like.

A reagent composition for use as a first reagent composition in a method of quantifying a small dense LDL cholesterol (sdLDL-C) in a sample, the method including causing the first reagent composition to react to the sample, and after the causing the first reagent composition to react to the sample, causing a second reagent composition for quantifying the sdLDL-C to react, thereby quantifying cholesterol in a remaining lipoprotein, the reagent composition includes a nonionic surfactant and has cholesterol esterase activity, cholesterol oxidase activity, and sphingomyelinase activity, and a contact angle between the reagent composition and a polyethylene terephthalate (PET) base material is equal to or more than 63.0 and equal to or less than 67.0.