Magnetic nanoparticles with dendrimer-assisted boronate avidity for the selective enrichment of trace glycoproteins

Abstract

Boronic acid-functionalized materials have been the subject of increasing attention in recent years due to their capability in the facile selective extraction of glycoproteins. However, boronic acids are associated with weak binding affinity, and it is thereby difficult for boronate affinity materials to extract glycoproteins of low concentration. Here we present for the first time a boronate avidity material, dendrimeric boronic acid-functionalized magnetic nanoparticles, with significantly enhanced binding strength towards glycoproteins. Due to the dendrimer-assisted multivalent synergistic binding, the boronate avidity material exhibited dissociation constants of 10 À5 to 10 À6 M towards glycoproteins, which are 3-4 orders of magnitude higher than the affinities of single boronic acid binding. Such an avidity enabled the selective extraction of trace glycoproteins; an extractable concentration as low as 2 Â 10 À14 M was demonstrated. Meanwhile, the boronate avidity material was tolerant of the interference of abundant competing sugars. Moreover, the dendrimeric boronic acid-functionalized magnetic nanoparticles exhibited two additional advantages: high binding capacity and fast binding/ desorption speed. Due to these favourable features, the selective enrichment of trace glycoproteins by the boronate avidity material became not only possible but also efficient. Efficient enrichment of trace glycoproteins from human saliva was demonstrated. The dendrimer-assisted synergistic binding strategy is also applicable to other types of boronic acid-functionalized materials and other types of functionalized materials.

A high boronate avidity monolithic capillary for the selective enrichment of trace glycoproteins

“…The K d value of the PDMC column for HRP was lower than that of PAMAM dendrimer-amplifed boronate avidity MNPs ((1.0 ± 0.1) × 10 −6 M)) [53] by only 1 order of magnitude. However, the K d value of the PDMC column for TRF was lower than that of PAMAM dendrimer-amplifed boronate avidity MNPs ((2.7 ± 0.0) × 10 −5 M)) [53] by 2 orders of magnitude.…”

“…Determination of dissociation constant (K d ) was carried out according to a previously reported method [48,53]. The monolithic column (250 m I.D.)…”

“…Finally, the components bound on the column were eluted by 110 L of 100 mM HAc (pH 2.7) solution. Dissociation constant (K d ) and apparent maximum binding capacity (Q max ) were calculated according to the following Scatchard equation [48,53]:…”

“…Furthermore, a recent study revealed that the binding strength of molecular interactions, including boronate affinity interaction, can be apparently enhanced by nanoscale spatial confinement [52]. On the other hand, synergistic effect of simultaneous multiple binding has proved to be an effective strategy for enhancing the binding strength of boronic acid-functionalized materials [53]. Through amplification of the number of boronic acid moieties using highly branched poly(amidoamine) (PAMAM) dendrimers, dendrimeric boronic acid-functionalized magnetic nanoparticles (MNPs) exhibited significantly enhanced binding strength toward glycoproteins, with K d values within of 10 −5 -10 −6 M. For convenience to differentiate affinity due to synergistic multiple binding from that due to single binding, the former is referred to as avidity while the latter is still remained as affinity.…”

Preparation of Molecularly Imprinted Polymers Functionalized with Core–shell Magnetic Nanoparticles for the Recognition of Glycoprotein

“…This reversible binding has made boronic acids excellent affinity ligands for creating functionalized materials [4][5][6].…”