A method for the in situ derivatization of at least one biogenic amine, precursor, or metabolite thereof in an isolated aqueous sample includes the steps of: (i) contacting the sample with a propionic anhydride/acetonitrile solution in the presence of a phosphate buffer having a pH in the range of 7.0 to 9.0 and allowing the conversion of amine and/or hydroxyl moieties of the biogenic amine, precursor, or metabolite thereof to form a propionyl derivative of the biogenic amine; followed by (ii) adding to the reaction mixture obtained in step (i) a carbodiimide compound and an electrophilic amine-containing compound, and allowing the carbodiimide-mediated derivatization of carboxylic acid moieties of the biogenic amine, precursor, or metabolite thereof.

A sensor can selectively detect quantum signatures in charge transfer processes via a tunneling current. In one aspect, the sensor can include a metal electrode having a first surface and a second surface. The sensor can also include an insulator film having a first thickness, a first surface area and a first surface chemistry. The insulator film can be coupled to the metal electrode via the first surface. The sensor can also include a functionalization film having a second thickness, a second surface area and a second surface chemistry. The functionalization film can be coupled to the metal electrode via the second surface. The insulator film and the functionalization film are configured to separate the metal electrode from an electrochemical solution comprising the analyte.

A peptide aptamer for specific recognition of arginine and its application are provided. The sequence of the peptide aptamer is shown in SEQ ID No. 1. The peptide aptamer is modified by a group that improves stability, or by a fluorescent group, an isotope and an electrochemical group that provide a detection signal, or by an affinity ligand and a mercapto. According to the computer-aided molecular docking simulation prediction, the peptide aptamer that can specifically bind to L-arginine is screened, which is verified by an isothermal titration calorimeter. The peptide aptamer has the advantages of good stability, strong binding ability, high specificity and low production cost.

An amino acid-specific binder selectively binds to a binding amino acid. A binder complex selectively identifies the binding amino acid and includes an adjunct attached to the amino acid-specific binder. The adjunct includes a taggant, protein, substrate, or chemical modifier. Selectively identifying an N-terminal amino acid includes anchoring a C-terminal end; contacting an N-terminal amino acid of the anchored analyte with the binder complex; selectively binding when the N-terminal amino acid includes the binding amino acid; producing, by the taggant of the tagged complex, a taggant signal; detecting the taggant signal; and identifying the N-terminal amino acid based on the taggant signal.

The disclosure generally relates to the detection of symmetrical dimethylarginine (SDMA). More particularly, the disclosure relates to the detection of SDMA using a solid phase. The disclosure provides devices, reagents, kits and methods for detecting symmetrical dimethyl arginine (SDMA) in sample, such as a biological sample from an animal. The method includes detecting the presence or amount of SDMA in the sample by using an immunoassay format, such as a competitive immunoassay. The assay includes the use of antibodies to SDMA that are specific for SDMA and that have less affinity for other arginine derivatives.

The present invention belongs to the technical field of analysis and detection and provides a method for detecting a selenoamino acid in a selenoprotein. The detection method includes: (1): mixing 10-30 mg of a selenoprotein sample with hydrochloric acid, and hydrolyzing with microwaves at 140-170° C. for 10-40 min to obtain a hydrolysate; (2): adjusting pH of the hydrolysate to 6-8 to obtain a pretreated solution; and, (3): detecting a selenoamino acid in the pretreated solution with high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS) to obtain a content of the selenoamino acid. The method is simple in operation and provides an accurate and reliable result, and also reduces time and cost.

An improved chemical probe for the detection of the amino acid citrulline combines: 1) a reactive head formed of 1,3-dicarbonyl moiety that reacts with a citrulline side chain in an improved manner compared to currently used 1,2-dicarbonyl moieties; and 2) a modular action of the probe where citrulline side chains are labeled first using reactive heads described above, and attachment of a read-out subunit or tag, be it a fluorophore, a nanoparticle, or an antigen is performed separately. The modular nature of the chemical probe increases the sensitivity of the probes due to their smaller size. Additionally, the chemical probes of the present disclosure allow the same sample to be analyzed using a variety of read-out methods.

Disclosed are devices, systems and methods for minimally-invasive and continuous analyte monitoring for closed-loop applications, such as drug delivery. In some aspects, a multi-modal microneedle sensing platform for continuous minimally-invasive orthogonal electrochemical monitoring of levodopa (L-Dopa) is disclosed, which uses parallel simultaneous independent enzymatic-amperometric and non-enzymatic voltammetric detection of L-Dopa using different microneedles on the same sensor array patch.

A biomarker panel for discriminating lung cancer comprises the biomarkers valine, lysoPhosphatidylcholine acyl C18:2 (Lyso PC a18:2), decadienyl-L-carnitine (C10:2) phosphatidylcholine, acyl-alkyl C36:0 (PC aa C36:0), phosphatidylcholine diacyl C30:2 (PC aa C30:2), spermine, and diacetylspermine.

Method of detecting Symmetrical dimethyl arginine (SDMA) in biological samples. SDMA analogs for generating anti-SDMA antibodies having little or no cross-reactivity with asymmetrical dimethyl arginine, arginine, and monomethylarginine. The analogs have a protected or free thiol (—SH) group or hydroxyl (—OH) group that allow them to be linked to a suitable conjugation target which can be, for example, a protein containing molecule of a label. The anti-SDMA antibodies can be used in diagnostic immunoassay for the diagnosis of SDMA associated disorders and/or diseases.