Polydopamine as an adhesive coating for open tubular capillary electrochromatography

Abstract

Polydopamine (PolyD) coating was used as an adhesive layer in the preparation of biological stationary phases for open tubular capillary electrochromatography (OT-CEC). The influence of coating solution freshness, coating time, temperature and dopamine hydrochloride concentration on the PolyD layer formation was studied. The performance of the polyD coating was monitored by measuring the electro-osmotic flow in coated capillaries. Following polyD coating of the capillary, secondary layer material (e.g. cell membrane solutions, phospholipid mixtures or mitochondria) was inserted into the capillary for at least 1 h. The performance of these double-coated capillaries (a polyD layer+a biological material layer) was compared with capillaries containing the respective biological material directly attached to the capillary wall. The study reveals that the presence of polyD layer in fused silica capillaries improves the performance of lipid and membrane fragment coatings in capillaries. At the same time, the thickness of the polyD layer does not have marked impact on the secondary coatings. Analysis with test analytes demonstrated that double-coated capillaries can be applied to study membrane-drug interactions.

Deposition Mechanism and Properties of Thin Polydopamine Films for High Added Value Applications in Surface Science at the Nanoscale

“…Molecules containing amino and thiol groups bind covalently to polydopamine films in a one-step reaction [36,[87][88][89][90] Polymerization initiators can be bound to polydopamine films to perform RAFT [36,111,112] Antibacterial coatings Silver ions are reduced in contact with polydopamine and form silver nanoparticles. However, silver is leached in the bacterial suspension and a second reduction step of Ag + cations in Ag is not possible [83,99] Membranes for separations and fuel cells Modification of a polysulfone membrane to make it permselective [78] The permselectivity of polydopamine is pH dependent and also depends on the synthesis method [79,80] Improvement of methanol barrier in fuel cells [102] Films for sensing Highly selective sensing of an analyte can be obtained by imprinting the molecule of interest in the polydopamine film during its formation [104][105][106] Coating of particles for the production of hollow capsules…”

“…Such coated capillaries where non-adhesive for proteins allowing to increase the efficiency of their separation in capillary electrophoresis [89]. In a different manner, a polydopamine coating can be used as an adhesive layer for open tubular electrochromatography [90].…”

Applications of polydopamine modifications in capillary electrophoretic analysis

“…In addition, Martma et al. developed a biological stationary phase via physically adsorbing cell membrane solutions, phospholipid mixtures, or mitochondria onto the inner wall of PDA‐modified capillary column. Four anionic compounds (rutin, quercetin, caffeic acid, and salicylic acid) can be separated in lipid‐coated capillary, while only rutin and quercetin were separated in membrane fragments‐coated capillary.…”

Open tubular‐capillary electrochromatography: Developments and applications from 2013 to 2015

“…Polydopamine (PDA) is a cross‐linked homopolymer easily formed from the oxidative self‐polymerization of dopamine (3,4‐dihydroxyphenyl‐L‐alanine) and has been recognized for its excellent adhesive ability and ease of forming thin‐layer films on various types of surfaces . Because of these properties, PDA has been extensively used to prepare PDA‐modified composites, and has been used for OT‐CEC applications as a strongly hydrophilic static coating. In further developments, Xiao and coworkers employed PDA for protein separations, with ammonium persulfate used as an alternative oxidant to induce the self‐polymerization .…”