Fast screening method for early diagnostic of gastric cancer based on utilization of a chitosan - S-doped graphene - based needle stochastic sensors.

Needle stochastic sensors were developed for the assay of carbohydrate antigen 19-9 (CA 19-9) and carcinoembryonic antigen (CEA) in different biological samples (e.g., whole blood, tissues, urine, and saliva).

Rhodamine B - as New Chromophore for the Determination of Melatonin in Biological, Food, and Pharmaceutical Samples.

Aim And Objective: Melatonin is an essential biomarker for sleep-related disorders. Reliable methods of analysis are needed for melatonin. Therefore, a new chromophore (Rhodamine B) was proposed for the assay of melatonin; this method succeeded to enlarge the working concentration range and to decrease the limit of determination comparing with the method that just used the native fluorescence of melatonin.