Boronic Acid Functionalized Nanosilica for Binding Guest Molecules

Abstract

Dendritic fibrous nanosilica (DFNS) has very high surface area and well-defined nanochannels; therefore, it is very useful as supporting material for numerous applications including catalysis, sensing, and bioseparation. Due to the highly restricted space, addition of molecular ligands to DFNS is very challenging. This work studies how ligand conjugation in nanoscale pores in DFNS can be achieved through copper-catalyzed click reaction, using an optional, in situ synthesized, temperature-responsive polymer intermediate. A clickable boronic acid is used as a model to investigate the ligand immobilization and the molecular binding characteristics of the functionalized DFNS. The morphology, composition, nanoscale pores, and specific surface area of the boronic acid functionalized nanosilica were characterized by electron microscopy, thermogravimetric and elemental analysis, Fourier transform infrared spectroscopy, and nitrogen adsorption–desorption measurements. The numbers of boronic acid molecules on the modified DFNS with and without the polymer were determined to be 0.08 and 0.68 mmol of ligand/g of DFNS, respectively. We also studied the binding of small cis -diol molecules in the nanoscale pores of DFNS. The boronic acid modified DFNS with the polymer intermediate exhibits higher binding capacity for Alizarin Red S and nicotinamide adenine dinucleotide than the polymer-free DFNS. The two types of boronic acid modified DFNS can bind small cis -diol molecules in the presence of large glycoproteins, due in large part to the effect of size exclusion provided by the nanochannels in the DFNS.

Sustained release of alpha‐methylacyl‐CoA racemase (AMACR) antibody‐conjugated and free doxorubicin from silica nanoparticles for prostate cancer cell growth inhibition

“…After grafting amino groups onto the MCM‐41 silica nanoparticles to form MCM‐N, distinct FTIR bands for amino groups were observed, which disappeared when the amino groups were tethered to phenylboronic acid groups to form MCM‐B. An amide bond was expected to be formed between the amino groups of MCM‐N and the display of peaks for CO and CN stretching at ~1654 and ~1627 cm −1 confirmed the formation of MCM‐B nanoparticles 51,53 …”

“…Amide bond formation of 4-carboxy phenylboronic acid with MCM-N and carbonyl at 1627 and 1654 cm À1 , respectively, confirm the formation of MCM-B. 53,54 The signals corresponding to the C O and C N stretches of the formed APTES linkages between the silica and the phenylboronic acid functionality in compound silica at 1654 cm À1 may be merged with the band of surface hydroxyl groups of silica and Si O Si band, respectively. 50,55 The characteristic peaks of both dextran and MCM-B are seen in Figure 2A where the spectrum for the dextran-capped MCM-B-D is shown.…”

“…An amide bond was expected to be formed between the amino groups of MCM-N and the display of peaks for C O and C N stretching at $1654 and $1627 cm À1 confirmed the formation of MCM-B nanoparticles. 51,53 The FE-SEM micrographs (Figure 5) showed that the silica nanoparticles were spherical in shape. However, the MCM-B-D nanoparticles were agglomerated due to the gelling effects of the dextran used to cap the nanoparticles.…”

Phenylboronic acid-derived nanovectors for gene/drug delivery by targeting cell surface glycans

“…The tumor microenvironment acts as a reduced buffer, donating electrons, while boron (in BA) itself acts as a Lewis acid; hence BA-containing nanoparticles act as Lewis acids, causing a shift in the boronic acid structure to the anionic tetrahedral type. 60,61 BA-based nanoparticles with a specific morphology influence the release of the drug/gene from the nanoparticle into the cytosol 62,63 (Fig. 1).…”

Preparation of Dendritic Mesoporous Silica Nanomaterials Loaded with Toosendanin-Fumaracetin and its Anti-Peripheral Pain Study

“…However, the clinical application of CMSN is limited, partly due to its potential cytotoxicity. Dendritic mesoporous silica nanomaterials (DMSN) is a novel porous material with three-dimensional open dendritic framework structure [16,17]. The central radiative pore structure possessed by DMSN is favorable for the delivery of drug components along the major radiative pore channels and has mild properties such as better biocompatibility and low toxicity,which have attracted considerable attention for its application in the field of drug delivery and biomedicine.Thus,this nanomaterial is a novel and promising carrier platform for clinical applications [18].…”