Novel Synthesis of Core-Shell Silica Nanoparticles for the Capture of Low Molecular Weight Proteins and Peptides

Abstract

Silica nanoparticles were functionalized with immobilized molecular bait, Cibacron Blue, and a porous polymeric bis-acrylamide shell. These nanoparticles represent a new alternative to capture low molecular weight (LMW) proteins/peptides, that might be potential biomarkers. Functionalized core-shell silica nanoparticles (FCSNP) presented a size distribution of 243.9 ± 11.6 nm and an estimated surface charge of −38.1 ± 0.9 mV. The successful attachment of compounds at every stage of synthesis was evidenced by ATR-FTIR. The capture of model peptides was determined by mass spectrometry, indicating that only the peptide with a long sequence of hydrophobic amino acids (alpha zein 34-mer) interacted with the molecular bait. FCSNP excluded the high molecular weight protein (HMW), BSA, and captured LMW proteins (myoglobin and aprotinin), as evidenced by SDS-PAGE. Functionalization of nanoparticles with Cibacron Blue was crucial to capture these molecules. FCSNP were stable after twelve months of storage and maintained a capacity of 3.1–3.4 µg/mg.

Bifunctional nickel–iminodiacetic acid-core–shell silica nanoparticles for the exclusion of high molecular weight proteins and purification of His-tagged recombinant proteins

“…This behaviour may be attributed to the hydrophilic nature of the organic compound attached to the core of nanoparticles, which form a dense layer that increases electrostatic repulsion at the surface and, therefore, increases particle size. 16,26 Finally, due to growth of the polymer chains 27,28 in shell formation, nanoparticles reached 479.6 AE 6.9 nm in size.…”

“…1(1). 16,31 In Fig. 1(2), new absorption peaks appeared at 1628 cm À1 , which correspond to C]C stretching vibrations 32 and another peak at around 1701 cm À1 associated to C]O groups of the monomer.…”

“…Phase 1-silica nanoparticles were obtained according to the modied Stöber method reported previously. 16 Briey, 40 mL of absolute ethanol, ammonium hydroxide (1.81 M) and tetraethyl orthosilicate (77 mM) were placed into a round-bottom and kept under stirring at room temperature for 24 h.…”

“…Silica nanoparticles with a uniform distribution were synthesized by the hydrolysis of TEOS with aqueous ammonia as reported previously. 16 The matrix silica nanoparticles were then functionalized with randomly distributed chemical groups for the addition of IDA by conjugation of imine groups of IDA to the epoxy groups of GLYMO 1 and formation of the polymeric shell by free radical polymerization of the monomer and bisacrylamide in presence of APS. 16 Synthesis of IDA-core-shell silica nanoparticles is shown in Scheme 1.…”

“…In this context, silica nanoparticles have appealing physical and chemical properties as a sorbent, due to its large surface area, low toxicity, high stability and particularly because it can be chemically modied with several compounds. 1,[16][17][18][19] The aim of this work was to synthetize functionalized core-shell silica nanoparticles with IDA and a polyacrylamide shell, thus only low molecular weight (LMW) His-tagged proteins that pass through the polymeric shell to interact with the immobilized metal ions, while other HMW host proteins with inherent histidine-rich region, are excluded.…”