Gold nanoparticle–mesoporous silica sheet composites with enhanced antibody adsorption capacity

Abstract

A notably high-capacity antibody adsorbent was prepared using dispersed gold nanoparticles immobilised on a mesoporous silica sheet. The mesoporous silica sheet (MPS sheet) was prepared via a dual-templating method using tetraethoxysilane and 3-aminopropyltriethoxysilane as the silica framework materials. Gold nanoparticles were loaded onto the amino-functionalised surface of the MPS sheet via deposition–precipitation using HAuCl₄ as the Au colloid precursor and then crystallised via calcination. The properties of the gold nanoparticle–silica composite and the dispersion of the nanoparticles were characterised using transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. The surface characteristics of gold nanoparticle composite materials calcined at different temperatures were also evaluated using Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetry data. The silica–gold nanoparticle composite sheet crystallised at 550 °C (sheet-Au-550) was mesoporous in character (pore diameter = 3.8 nm) with a BET surface area of 258.0 m² g⁻¹. With respect to antibody adsorption, the sheet materials had a relatively higher capacity than the typical cylindrical mesoporous silica, and sheet-Au-550 exhibited a strong performance (maximum adsorption quantity Q_Max = 0.26 mg IgG per mg carrier). In addition, the IgG adsorption equilibrium for sheet-Au-550 fits the Langmuir isotherm model better than the Freundlich plot model. These results will be very useful for the design of adsorption materials for biomolecules, such as antibodies.