Electron capture dissociation, electron detachment dissociation, and collision-induced dissociation of polyamidoamine (PAMAM) dendrimer ions with amino, amidoethanol, and sodium carboxylate surface groups

Abstract

Here, we investigate the effect of the structure (generation) and nature of the surface groups of different polyamidoamine (PAMAM) dendrimers on electron-mediated dissociation, either electron capture dissociation (ECD) or electron detachment dissociation (EDD), and compare the fragmentation with that observed in collision-induced dissociation (CID). ECD and EDD of the PAMAM dendrimers resulted in simple mass spectra, which are straightforward to interpret, whereas CID produced complex mass spectra. The results show that electron-mediated dissociation (ECD and EDD) of PAMAM dendrimers does not depend on the nature of the surface group but tends to occur within the innermost generations. CID of the PAMAM dendrimers showed a strong dependence on the nature of the surface group and occurred mostly in the outer generation. The results demonstrate the potential utility of ECD and EDD as a tool for the structural analysis of PAMAM dendrimers.

MALDI In-Source Decay Mass Spectrometry of Polyamidoamine Dendrimers

“…For all the matrices, S/E-type fragmentations at tertiary amine sites prevailed, accounting for more than 80 % of all fragmentations. Formation of abundant S-and E-fragments agrees with previous ECD results [19,20], suggesting that S/Etype cleavages are products of a radical-induced pathway occurring via homolytic bond cleavage. Radical-induced homolytic bond cleavages were also observed previously in ECD and activated electron photo-detachment experiments for other synthetic polymers [22,23].…”

“…In parallel with their growing applications, the demand for a suitable characterization method is also increasing. Consequently, many tandem MS techniques such as collision-induced dissociation (CID), ECD, and electron detachment dissociation (EDD) have been successfully examined for analyzing PAMAM dendrimer structure [19][20][21]. In this application note, we demonstrate that MALDI-ISD MS provides a simple and inexpensive means to characterize dendritic polymers, yielding rich structural information without tandem MS techniques.…”

“…To assign MALDI-ISD spectra, we employed the fragment notations that we previously proposed for PAMAM dendrimers (see Scheme 1c) [19][20][21]. In brief, we used the form G n (l), where n is the generation number of the cleavage site and l is the fragmentation type (a/x, b/y, c/z, S in/out , or E in/out ).…”

“…PAMAM dendrimers are a class of synthetic polymers with a dendritic architecture consisting of an alkyl-diamine core and tertiary amine branches with a repeating amide functionality. In addition, PAMAM dendrimers inherently possess a high degree of monodispersity [18][19][20][21]. The dendritic structure and various surface functionalities of PAMAM dendrimers have many important applications in materials science and biotechnology, including drug delivery and biomedical imaging.…”

Bioengineering Strategies for Designing Targeted Cancer Therapies

“…Various surface functional groups may be used to modify the surface charge of the dendrimer. Figure used with permission from (Kaczorowska and Cooper, 2008). …”