A bioconjugated design for amino acid-modified mesoporous silicas as effective adsorbents for toxic chemicals

Enantioselective effect of cysteine functionalized mesoporous silica nanoparticles in U87 MG and GM08680 human cells and Staphylococcus aureus bacteria

Chirality is a fundamental phenomenon in biological systems, since most of the biomolecules and biological components and species are chiral and therefore recognize and respond differently depending on the enantiomer present. With increasing research into the use of nanomaterials for biomedical purposes, it is essential to understand the role that chirality of nanoparticles plays at the cellular level. Here, the chiral cysteine functionalization of mesoporous silica nanoparticles has been shown to broadly affect its interaction with U87 MG human glioblastoma cell, healthy human fibroblast (GM08680) and methicillin-resistant S. aureus bacteria. We believe that this research is important to further advancement of nano-biotechnology.

Investigating Microcystin-LR adsorption mechanisms on mesoporous carbon, mesoporous silica, and their amino-functionalized form: Surface chemistry, pore structures, and molecular characteristics

Microcystin-LR (MC-LR) is the most common cyanotoxin released from algal-blooms. The study investigated the MC-LR adsorption mechanisms by comparing adsorption performance of protonated mesoporous carbon/silica (MC-H, MS-H) and their amino-functionalized forms (MC-NH₂ and MS-NH₂) considering surface chemistry and pore characteristics. The maximum MC-LR adsorption capacity (Langmuir model) of MC-H (37.87 mg/g) was the highest followed by MC-NH₂ (29.25 mg/g) and MS-NH₂ (23.03 mg/g), because pore structure is partly damaged during amino-functionalization. However, MC-NH₂ (k₂ = 0.042 g/mg/min) reacted faster with MC-LR than MC-H during early-stage adsorption due to enhancing electrostatic interactions. Intra-particle diffusion model fit indicated K_p,1 of MC-H (2.11 mg/g/min^1/2) was greater than MC-NH₂ due to its greater surface area and pore volume. Also, large mesopore diameters are favorable to MC-LR adsorption by pore diffusion. The effect of adsorbate molecular size on adsorption trend against MC-H, MC-NH₂ and MS-NH₂ was determined by kinetic experiments using two dyes, reactive blue and acid orange: MS-NH₂ achieved the highest adsorption for both dyes due to the large number of amino groups on its surface (41.2 NH₂/nm²). Overall, it was demonstrated that adsorption of MC-LR on mesoporous materials is governed by (meso-)pore diffusion and π - π (and hydrophobic) interactions induced by carbon materials; in addition, positively-charged grafted amino groups enhance initial MC-LR adsorption rate.