Changsha University of Science and Technology

Chinese Academy of Sciences

Zhong Cao

Zhongliang Xiao

Qin Zhu

Jinglin He

Zemeng Feng

Yulong Yin

Chen Liu

Yumin He

Li Zhou

Jiaxin Li

Saifei Feng

Huiying Hu

Donghong Yu

Chu Liu

Dan Li

Min Jin

Ling Zhang

Yuyang Zhang

Jia Yang

Ningtao Zhou

Yuyu Peng

Ling Tang

Lei Deng

Junyi He

A method for a selective detection of L-tryptophan (L-Trp) using formaldehyde as a medium is disclosed. The method includes preparation of a copper sulfide nanosheets-chitosan/acidified functionalized multi-wall carbon nanotubes (CuS NS—CS/F-MWCNTs) composite material, preparation of a composite film-modified electrode CuS NS—CS/F-MWCNTs/GCE, and a detection of the L-Trp. Since oxidation peaks of L-Trp and L-tyrosine (L-Tyr) overlap and are difficult to separate, the present invention provides a method for a highly selective detection of L-Trp through the Pictet-Spengler reaction of formaldehyde (HCHO) with L-Trp, in which the oxidation peak potential of L-Trp is shifted to 0.82 V and the oxidation peak potential of L-Tyr is 0.63 V, thereby effectively avoiding the interference of L-Tyr. The CuS NS—CS/F-MWCNTs/GCE is applied to detect L-Trp in the formaldehyde medium without any interference from L-Tyr or other amino acids with 50-fold concentrations.

Method for selective detection of L-tryptophan using formaldehyde as medium

A method and a sensor for detecting L-cystine are disclosed. The method is implemented by assembling a sodium 3,3′-dithiodipropane sulfonate (SPS) membrane on a surface of Au membrane layer of an Au electrode and using an extended gate of field effect transistor (FET) and in-situ signal amplification of the FET to detect L-cystine sensitively. The polyanion of the SPS membrane adsorbs and binds a positively charged target L-cystine through electrostatic interaction, thus forming an electric double layer structure to generate a membrane potential identifying a monovalent organic ammonium ion. The sensor includes the FET, wherein a gate-extended gold electrode is arranged on the FET, and the SPS membrane is assembled on the surface of the Au membrane layer of the gate-extended gold electrode. The sensor has an excellent Nernst response to L-cystine.

Method and sensor for detecting L-cystine

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.

Peptide aptamer for specific recognition of arginine and its application

A method and a sensor for detecting L-arginine are provided. The method includes synthesizing ferrocene-functionalized hexadecapeptide dithiocyclopentane (FC-P16 Peptide), preparing a polypeptide composite membrane-modified electrode (FC-P16 Peptide/AuE), detecting L-Arg and other steps. The results show that the polypeptide composite membrane-modified electrode (FC-P16 Peptide/AuE) exhibits excellent electrochemical response properties to L-Arg. In 10 mmol/L phosphate-buffered saline (PBS, pH=7.4), the DPV response peak current of the polypeptide composite membrane-modified electrode has an excellent linear relationship with the L-Arg concentration of 1.0&#xd7;10mol/L to 1.0&#xd7;10mol/L, with a detection limit of 1.0&#xd7;10mol/L. With prominent reproducibility, repeatability and selectivity, the modified electrode has potential application in life science and nutritional health.

Method and sensor for detecting L-arginine

A method and a sensor for detecting L-cysteine based on a 3,3'-dithiobis (1-propanesulfonate)-mercury composite membrane are provided. The method includes: implanting a p-well and an N-type substrate on field effect transistor substrate, constructing a source electrode and a drain electrode at the p-well, constructing a silicon dioxide layer on the substrate, plating an aluminum-copper alloy layer, a chromium-palladium alloy layer, and a gold film layer on a polysilicon gate substrate, constructing a silicon nitride layer on the substrate and the silicon dioxide layer; extending a gate part; preparing an ethanol solution of disodium 3,3&#x2032;-dithiobis (1-propanesulfonate), cleaning and soaking gate gold electrode in the solution, followed by soaking in an ethanol solution of mercuric nitrate, and then washing the gate gold electrode; connecting electrode interfaces, inserting the electrode into PBS, and connecting power interfaces to a stabilized voltage supply, connecting a signal output interface to a multimeter.

Method and sensor for detecting l-cysteine based on 3,3'-dithiobis (1-propanesulfonate)-mercury composite membrane

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Zhong Cao