To provide a method for simply and precisely measuring cholesterol (LDL-C) in low-density lipoprotein in a sample without use of any surfactant having an alkylphenol structure, in terms of environmental friendliness. A method for measuring LDL-C in a sample, the method comprising: reacting the sample with (i) a combination of cholesterol ester hydrolase and cholesterol oxidase or (ii) a combination of cholesterol ester hydrolase, an oxidized coenzyme and cholesterol dehydrogenase, in an aqueous solvent which comprises: [a] one or more surfactants selected from the group consisting of a polyoxyethylene alkyl ether and a polyoxyethylene polyoxypropylene alkyl ether; and [b] a polyoxyethylene polyoxypropylene copolymer; and which does not comprise any surfactant having an alkylphenol structure; and measuring a substance formed or consumed in the reaction.

The invention provides compositions and systems that allow the sensitive determination of the level of creatinine in a particular solution. Through the optimisation of enzymatic methods to detect creatinine the real-time determination of creatinine levels and creatinine clearance rates are also provided, allowing the real-time monitoring of kidney function. This is considered to be useful both in the monitoring of live subjects, and in the monitoring of isolated organs, such as a kidney, intended for transplantation.

An ascorbic acid responsive electrode comprising an electrode, and a detection layer comprising a non-catalytic electron acceptor that receives an electron from ascorbic acid, an amino acid, and a saccharide and/or a soluble protein; wherein in the detection layer the electron acceptor is reduced by the ascorbic acid, and the reduced electron acceptor is oxidized at the electrode.

Described are methods for generating a reporter molecule in response to a target analyte in a cell-free system. A synthetic biological circuit is used to modify the level of the reporter molecule in response to the presence of the target analyte. The reporter molecule may be glucose or another molecule readily detected using a device such as glucose monitor or other portable sensor. Also provided are kits comprising a cell-free system with a synthetic biological circuit that generates or consumes a reporter molecule in response to a target analyte.

Devices and methods for sensing analytes in a solution sample are provided. The device includes a substrate, a conversion component configured to convert the analyte in the sample solution into a metabolite, and an aptamer sensor configured to measure a presence of the metabolite, the aptamer sensor located on the substrate.

Provided herein are methods of detecting or determining aging and/or oxidative damage in tissue, including placental tissue, skin, kidney and brain tissue. One embodiment provides a method for detecting or determining aging in body tissue, comprising measuring one or more markers of aldehyde oxidase 1 (AOX1) expression or activity in a biological sample, wherein the level of AOX1 expression or activity, or of the one or more markers, is indicative of aging in the tissue. Also provided herein are methods of treating a disease or condition associated with ageing or oxidative damage in one or more cells or tissues, comprising administering to a subject in need thereof an inhibitor of AOX1.

Provided is a compound having the structure:

(SIG)-(SI-MOD).sub.m

where SIG is a signaling molecule, SI is a self-immolative structure bound to SIG such that SIG has a reduced signal relative to the signal of SIG without SI, MOD is a moiety bound to SI that is subject to modification by an activator, and m is an integer from 1 to about 10. When MOD is modified by an activator, SI is destabilized and self-cleaved from SIG such that SIG generates an increased signal. Also provided are methods of determining whether a sample, such as a cell, comprises an activator, such as a nitroreducase, using the compound. Further provided are methods of determining whether a mammalian cell is hypoxic using the compound where nitroreductase is the activator. A method of detecting a microorganism that comprises a nitroreductase using the compound where nitroreductase is the activator is also provided.

A CMOS-based chip having multiple sensing modalities that are able independently to detect multiple metabolites present in a sample. In particular, the chip provides multiple sensing modalities capable of performing detection within the same physical test volume, i.e. the chip can simultaneously detect a plurality of chemical reactions occurring in the test volume, where each chemical reaction yields a result that is independently detectable. The chip may comprise an optical sensor (e.g. photodiode) and a chemical sensor (e.g. pH sensor, embodied as an ISFET). With this technique, multiple metabolites may be measured in real time using a small scale point-of-care device.

Provided is a compound having the structure:
(SIG)-(SI-MOD).sub.m
where SIG is a signaling molecule, SI is a self-immolative structure bound to SIG such that SIG has a reduced signal relative to the signal of SIG without SI, MOD is a moiety bound to SI that is subject to modification by an activator, and m is an integer from 1 to about 10. When MOD is modified by an activator, SI is destabilized and self-cleaved from SIG such that SIG generates an increased signal. Also provided are methods of determining whether a sample, such as a cell, comprises an activator, such as a nitroreducase, using the compound. Further provided are methods of determining whether a mammalian cell is hypoxic using the compound where nitroreductase is the activator. A method of detecting a microorganism that comprises a nitroreductase using the compound where nitroreductase is the activator is also provided.

Cancers of different cellular or tissue origins express different ENOX2 cancer isoforms or combinations of isoforms and shed these proteins into the circulation. Herein are disclosed methods both for cancer detection and diagnosis of particular origin, based on the patterns and molecular weights of the isoforms which allow the identification of the cell type and or tissue of origin of the neoplasm. Relative ENOX2 amounts are proportional to tumor burden and provide a reliable measure of response to therapy and disease progression. Also provided is the amino acid sequence to which the scFv antibodies bind as the molecular basis for the specificity of the test.