UPLC-ESI-TOF-MS Analysis of the Effect of Dendrimers Core Lengths on Their Molecular Profiles and Purity

Abstract

The effect of core length of Polyamidoamine (PAMAM) dendrimers on their physicochemical properties and hence their purity was studied by ultraperformance liquid chromatography-electrospray ionization-time of flight-mass spectrometry (UPLC-ESI-TOF-MS). Seven consecutive generations Gn = (G0-6) of both Ethylenediamine core (C2) and Diaminobutane core (C4) dendrimers were tested. The separation and detection of each generation of dendrimers (covering a molar mass range of 517-58,076 Da and a radius range of 15-67 Å) were performed within 10 min. Increasing the length of the core by the C2H4 group significantly changed the morphological characteristics of the dendrimers. For example, the general morphology of C4 dendrimers becomes less compact than C2 dendrimers. This facilitates the influx of impurities from the inner nanocavities of these molecules, even at higher generations, during the UPLC run providing C4 dendrimers of higher purity than C2 dendrimers. These results reveal that the toxicity found by some researchers due to the application of dendrimers may be mostly due to leakage of the encapsulated starting materials, which can be eliminated by using optimized dendritic molecules.12