Use of poly(vinyl alcohol)‐coated capillaries for separation of amino‐terminated polyamidoamine dendrimers

Abstract

Characterization of amino-terminated polyamidoamine dendrimers by CE suffers from a lack of resolution for higher generations and poor between-day reproducibility of retention times. Under optimal conditions of temperature, voltage, and sample amount, 0-5 generations of dendrimers could be resolved with a bare fused-silica capillary. However, reproducibility was poor due to potential interactions of the polycationic dendrimers with the uncoated quartz capillary wall. Use of a poly(vinyl alcohol)-coated capillary significantly decreased the migration times of the nanomolecules without compromising resolution. Dendrimer mixtures containing generations 0-5 are separated as discrete, nonoverlapping peaks in about 15 min. In addition, the between-day precision of retention times was dramatically improved without the need for internal standards or data normalization. Dendrimers of various generations and cores run on different days showed an RSD of retention times of less than 4%. The poly(vinyl alcohol) coating was very stable as shown by the excellent precision of migration times obtained on a capillary used for a month with more than 100 injections. Similar to PAGE, separation of polyamidoamine dendrimers on a bare fused-silica and poly(vinyl alcohol)-coated capillary showed an exponential relationship between migration times and calculated charge density of the nanomolecules.

CE of poly(amidoamine) succinamic acid dendrimers using a poly(vinyl alcohol)‐coated capillary

“…3 and Table 1 is that the migration times of PAMAM-SAH dendrimers decreases with the number of the dendrimer generation, which is opposed to the separation profiles of polycationic PAMAM dendrimers in other studies [28,31]. These experiments were repeated and, on each trial, highly reproducible results were obtained (e.g., the SDs of migration times for all generations were less than 0.23 min (Table 1)).…”

“…Since the use of a PVA-coated capillary achieved a reproducible separation for polycationic PAMAMs [31], we attempted to characterize polyanionic dendrimers using CE on a similar PVA-coated capillary. Figure 2a shows the separation of a generation 5 PAMAM-SAH dendrimer (G5.SAH).…”

“…In order to improve the separation reproducibility, the surface of the capillary was modified through silanization [26][27][28][29], dynamic polymer coating [35], or permanent polymer coating [31] to decrease the interaction of the polycationic dendrimers with the capillary surface. A recent report shows that separation of polycationic PAMAM dendrimers using a poly(vinyl alcohol) (PVA)-coated capillary can achieve excellent reproducibility [31].…”

Recent progress of polar stationary phases in CEC and capillary liquid chromatography

“…By taking the advantage of the hydrophilicity of PVA, Carter and Ajit Sharma 20 achieved the separation of polyamidoamine dendrimers based on the electrophoretic migration and the hydrogen bonding interaction on the PVA‐coated capillary. Comparing to the bare fused silica, the PVA‐coated capillary provided a stable surface with an optimum hydrophobic–hydrophilic balance for dendrimers separation without the need of any cumbersome washing procedures, buffer additives or data normalization.…”

Neutral Coatings for the Study of Polycation/Multicharged Anion Interactions by Capillary Electrophoresis: Application to Dendrigraft Poly-l-lysines with Negatively Multicharged Molecules

“…CE presents the advantage to require only minute amount of sample. As CE was successfully implemented to separate dendrimers of different generations ,, or to describe functionalized dendrimers, ,, it seems particularly attractive to investigate the interactions developed by dendritic structures.…”