Embodiments described herein relate to devices, and methods for quantifying thiol content in a sample containing a mixture of proteins or protein isoforms. The method includes conjugating a portion of the sample with free thiol detection binders, separating the contents in the portion of the sample into separated protein isoforms, detecting fluorescence signals associated with each separated protein isoform, and quantifying, based on the fluorescence signals, a relative amount of free thiol associated with each separated protein isoform. In some instances, the method includes quantifying the amount of each separated protein isoform based on absorbance signals associated with each separated protein isoform. In some instances, the fluorescence and/or absorbance signals associated with protein isoforms conjugated with detection binders can be compared with the corresponding signals associated with unconjugated protein isoforms. In some instances, the method further includes applying a reducing agent and quantifying total-thiol content in the sample.

The present invention relates to a dynamic chemical network that mimics the transfer of information and ultimately produces a chemical response, for example a readable signal. More specifically, the invention discloses a dynamic system able to selectively sense a biologically-relevant analyte, such as cysteine, in its reduced or its oxidized form (cystine) in aqueous media and in a biofluid (such as urine) for diagnostic application. Due to this property, said dynamic system is useful for the detection of cysteine or its derivatives in biological fluids such as urine.

The invention relates to diagnostic methods for assessing the need of a subject for treatment with an anti-oxidant, or alternatively, for determining the utilization efficiency and ultimate effectiveness of anti-oxidant therapy in subjects having been treated with antioxidants. More specifically, the methods of the present invention are particularly useful in prophylactic assessment of individuals at risk for developing diseases or conditions in which oxidative stress plays a role, such that an appropriate therapeutic regimen can be prescribed for that individual, thus leading to alternative therapies and/or life style changes. The invention further relates to methods for assessing the need for, the utilization efficiency and the effectiveness of therapy in subjects having received therapy with specific antioxidant and immune enhancing formulations. Kits are also provided for measuring the levels of markers of oxidative stress and immune cell numbers.

Herein is disclosed a method for detecting a material comprising a thiol group (e.g. homocysteine, cysteine, glutathione) in a sample, the method comprising: providing an electrode comprising a carbon material; contacting said electrode with said sample in the presence of catechol or more generally a precursor of ortho-quinone; performing cyclic or square wave voltammetry to convert catechol to ortho-quinone and wherein said ortho-quinone reacts with the material comprising a thiol group to form an electrochemical reaction product.

The present disclosure relates to a composition for screening an intestinal environment-improving material and a screening method using the composition, and according to the composition and the method of the present disclosure, it is possible to provide an effective analysis method for screening a microbiota-improving candidate material in a personalized manner by providing a method for verifying personalized probiotics, prebiotics, foods, health functional foods and drugs under in vitro conditions based on microbiota and microbiota metabolites.

The present invention relates to compositions and methods for determining the absolute configuration of D/L-cysteine and/or the enantiomeric composition of cysteine and/or the concentration of total cysteine in a sample. Uses of the composition and method are also described.

MCE assays and reagents to assess purity and to identify impurities in protein drug product samples are provided. Methods for analyzing analytes in a protein drug sample are provided.

The present invention relates to a method of improving the quality of therapeutic cells by real-time glutathione monitoring.

The present invention provides a method for monitoring esophageal adenocarcinoma (EAC) disease progression in a subject, the method comprising: obtaining a biological sample from the subject; measuring with a quantitative analytical method at least one metabolite; determining a metabolomic biosignature of EAC disease progression based on a comparison of quantitative data for the at least one metabolite to corresponding data obtained for at least one reference sample; and identifying active EAC disease progression in the subject if the quantity of the at least one metabolite in the sample from the subject is greater than that found in the at least one reference sample.

The present invention provides a method of measuring the quality of therapeutic cells through real-time glutathione monitoring.