Impact of pre-concentration to covalently biofunctionalize suspended nanoparticles

Abstract

The effective biofunctionalization of nanoparticles is crucial for biomedical applications. In this study we investigated the covalent biofunctionalization of magnetic nanoparticles based on carbodiimide activation. An important aspect in the covalent biofunctionalization of nanoparticles has been neglected, namely pre-concentration. Exploiting the electrostatic attraction forces between a protein and the nanoparticle surface will favor the covalent immobilization. We showed that low ionic strength buffers with a pH slightly lower than the pI of the selected biomolecules is needed to increase the yield of covalent immobilization. Additionally, it is demonstrated that the covalently immobilized proteins are bioactive, relying on a sandwich assay using gold nanoparticles as reporter labels.

Affinity Comparison of p3 and p8 Peptide Displaying Bacteriophages Using Surface Plasmon Resonance

“…According to the SPR signal, the highest streptavidin density was realized in MES buffer with pH 6.0. This result is in accordance with the p I for both streptavidin (p I = 6.3) and biotin (p I = 3.5), making both molecules oppositely charged at pH 6.0, allowing them to diffuse closely to the surface which increases the chances for a binding event . Although these molecules should be even more oppositely charged at pH 5.2, a lower binding was observed.…”

Conjugation of insulin onto the sidewalls of single-walled carbon nanotubes through functionalization and diimide-activated amidation

“…25,26 The EDC/S-NHS activation method was preferred due to its high conversion efficiency and excellent biocompatibility, which minimizes any adverse effects on the bioactivity of target molecules. 27,28 The reaction pathway for the conjugation of insulin onto SWCNTs is shown in Figure 1.…”

“…In addition, the ionic strength of the buffer used during the conjugation of insulin onto the sidewalls of SWCNT may also have an effect on the amount of attached insulin, 28 where the adjustment of ionic strength could be performed by varying the pH of the buffer used in the amidation process.…”

Hyaluronic Acid Nanohydrogels as a Useful Tool for BSAO Immobilization in the Treatment of Melanoma Cancer Cells

“…To accomplish covalent enzyme immobilization on NHs, carbodiimide chemistry between HA‐CH free carboxylic group and protein lysine residues was used . NH‐BSAO was recovered by ultracentrifugation and, after dispersion in water, their dimensions increased up to 190 nm, because of the enzyme conjugation.…”