Rapid Capillary Zone Electrophoresis of Recombinant Erythropoietin by the Use of Dynamic Double Layer Coating

A comprehensive review of capillary electrophoresis-based techniques for erythropoietin isoforms analysis

Different CE techniques have been used to analyze erythropoietin. These techniques have been shown to be effective in differentiating and quantifying erythropoietin isoforms, including natural and recombinant origins. This review provides a comprehensive overview of various capillary electrophoresis-based techniques used for the analysis of erythropoietin isoforms. The importance of erythropoietin in clinical practice and the necessity for the accurate analysis of its isoforms are first discussed. Various techniques that have been used for erythropoietin isoform analysis are then described. The main body of the review focuses on the different capillary electrophoresis-based methods that have been developed for erythropoietin isoform analysis, including capillary zone electrophoresis and capillary isoelectric focusing. The advantages and drawbacks of each method as well as their applications are discussed. Suggestions into the future directions of the area are also described.

Label-free identification of Erythropoietin isoforms by surface enhanced Raman spectroscopy

We present a sensitive label-free surface enhanced Raman spectroscopy (SERS) method for the discrimination between the recombinant and endogenous human Erythropoietin (EPO) isoforms. The proposed methodology comprises a lectin-functionalised extractor chip for the extraction of the recombinant human EPO (rhuEPO) and the endogenous EPO (enEPO) from blood plasma. The disulfide bond molecular structure of the purified isoforms was modified to chemisorb the biomolecules onto a SERS substrate in a unified orientation, thus maximizing the reproducibility and sensitivity of the SERS measurements. The acquired SERS spectra of the EPO isoforms showed diagnostic Raman bands that allowed for the discrimination between rhuEPO and enEPO. The method was also used for the SERS quantification of rhuEPO and enEPO down to 0.1 pM and 0.5 pM, respectively. The SERS determination of the protein isoforms was cross validated against ELISA. The new SERS method has strong potential for the rapid screening of rhuEPO doping in athletes and for the therapeutic drug monitoring of rhuEPO treatment in cancer patients.