Polyamidoamine dendrimer-assisted 3-carboxybenzoboroxole-functionalized magnetic nanoparticles for highly efficient capture of trace cis-diol-containing biomacromolecules

Abstract

Boronate affinity materials have attracted more and more attention in recent years due to their highly selective capture of cis-diol-containing biomacromolecules. However, the use of single boronic acid ligands leads to conventional boronate affinity materials that can only provide a low binding affinity and binding capacity, making the extraction of trace cis-diol-containing biomacromolecules, such as glycoproteins, impossible or rather difficult. To this end, we developed polyamidoamine dendrimer-assisted boronic acid-functionalized magnetic nanoparticles (MNPs). We used a branched polyamidoamine dendrimer to amplify the number of boronic acid moieties as a scaffold. Meanwhile, 3-carboxybenzoboroxole was employed as an efficient affinity ligand, which exhibited high affinity and excellent water solubility toward cis-diol-containing biomacromolecules. Due to the combination of the dendrimer-assisted synergistic multivalent binding and 3-carboxybenzoboroxole, the boronate affinity materials exhibited high binding affinity toward glycoproteins, reaching dissociation constants of 10⁻⁷ M, which, for reported boronic acid-functionalized materials, is the highest except for boronate-affinity MIPs. This enabled the selective extraction of trace glycoproteins as low as 0.8 pg mL⁻¹. This feature favoured the selective enrichment of trace glycoproteins greatly from real samples. Meanwhile, the developed boronate affinity MNPs were tolerant of the interference of abundant sugars. In addition, the dendrimer-based boronate affinity MNPs exhibited high binding capacity and low binding pH (pH ≥ 5.0). With the selective enrichment of trace glycoproteins in human saliva, the feasibility for practical applications was demonstrated.