Photosensitive diazotized poly(ethylene glycol) covalent capillary coatings for analysis of proteins by capillary electrophoresis

Abstract

A new method for the fabrication of covalently cross-linked capillary coatings of poly(ethylene glycol) (PEG) is described using diazotized PEG (diazo-PEG) as a new photosensitive coating agent. The film of diazo-PEG depends on ionic bonding and was first prepared on the inner surface of capillary by self-assembly, and ionic bonding was converted into covalent bonding after reaction of ultraviolet light with diazo groups through unique photochemical reaction. The covalently bonded coating impedance adsorption of protein on the central surface of capillary and hence the four proteins ribonuclease A, cytochrome c, bovine serum albumin, and lysosome can be baseline separated by using capillary electrophoresis (CE). The covalently cross-linked diazo-PEG capillary column coatings not only improved the CE separation performance for proteins compared to non-covalently cross-linked coatings or bare capillary but also showed a remarkable chemical solidity and repeatability. Because photosensitive diazo-PEG took the place of the highly noxious and silane moisture-sensitive coating reagents in the fabrication of covalent coating, this technique shows the advantage of being environment-friendly and having a high efficiency for CE to make the covalently bonded capillaries.

Recent advances in column coatings for capillary electrophoresis of proteins

“…Physically N,N-CE-UV Lysozyme, [35] C -coating reagent CE-UV Lysozyme, cytochrome C, bovine serum [52] M A N U S C R I P T …”

“…Excellent separations were obtained for acidic and basic proteins with these hydrophilic coatings. Another type of covalent capillary coating was based on the use of a photosensitive diazo polymer [51,52]. Firstly, the diazo polymer was electrostatically adsorbed to the negatively charged (pH > 3) [55] bare fused silica capillary surface.…”

“…The physically adsorbed layer was then exposed to UV light forming the covalently cross-linked diazo coating. This coating was chemically stable and showed good performance in CE separation of proteins [52]. Guttman and coworkers [54] developed a fully automated covalent linear polyacrylamide (LPA) coating and regeneration procedure for CE of proteins, based on the original Hjertén approach [33].…”

Recent advances in protein analysis by capillary and microchip electrophoresis

“…Recently, the same group reported a new method for fabrication of covalently cross-linked poly(ethylene glycol) (PEG) in a capillary. 47 The authors used a diazotized PEG (Diazo-PEG) as a new photosensitive coating agent. The Diazo-PEG provided higher and more stable EOF suppression than DR/PEG previously reported by the same group.…”

A covalent capillary coating of diazoresin and polyglycerol dendrimer for protein analysis using capillary electrophoresis

“…For these reasons, CE has aimed a relatively big potential, especially in the fields of biomedical engineering, food security, and environmental protection analysis. However, interactions with the capillary wall can present a challenge in the use of CE for alpha‐1‐acid glycoprotein, glycoproteins , and related biomolecules . The presence of such interactions may lead to unstable electroosmotic flow (EOF), long migration times, and peak broadening during the analysis procedure .…”