Preparation of silica hydrogels using a synthetic peptide for application as carriers for controlled drug release and mesoporous oxides

Abstract

Solgel methods is a commonly used methods for encapsulation of enzyme and drug, but this method has two disadvantages of using acid or base as a catalyst and being difficult to control pore size of silica material. Even though synthesis under mild condition or silica with controlled pore size in the mesopore region have been reported, it is still difficult to achieve these two characteristics simultaneously. In this work, we chose 10-mer peptides of lysine (K), histidine (H), and block and alternate K and aspartic acid (D) as catalysts for silica mineralization, and silica gels were prepared using the synthetic peptides and a "leave to stand" synthesis method. The resulting silica hydrogels were lyophilized, and their surface areas and morphologies were characterized using the BrunauerEmmettTeller (BET) method and field-emission scanning electron microscopy (FE-SEM), respectively. Silica gels prepared by the "leave to stand" method with K 10 and H 10 exhibited a mesoporous structure with high surface area (576 and 451 m 2 g ¹1, respectively) and pore volume (0.35 and 0.30 cm 3 g ¹1 , respectively). SEM images confirmed the mesoporous structure of these gels. We encapsulated fluorescein sodium salt as a model drug within silica hydrogels using K 10 and H 10 as a catalyst. The silica hydrogel prepared using H 10 exhibited faster release of the drug (approximately 2.5-fold) than gels prepared using K 10 . These results demonstrate that by changing isoelectric point binding between the peptide and pore structure, the synthesized silica hydrogel-peptide composites can be designed to control the release rate of an encapsulated drug.

Composites of Polymer Hydrogels and Nanoparticulate Systems for Biomedical and Pharmaceutical Applications

“…In addition, due to their large specific surface area, controllable particle morphology and pore volume or interlayer space, excellent adsorption ability, ionic exchange capacity and outstanding adhesive ability, some silicon-based NPs, especially MSNs, MMT and LAP, have superb drug-carrying capability. They have been widely used to integrate into hydrogel drug delivery systems to increase drug-loading, manipulate drug pharmacological profiles, minimize drug degradation and decrease detrimental drug side effects [ 137 , 138 , 139 ]. We summarized the advances of nanocomposite hydrogels from hydrogels and silicon-based NPs for biomedical applications.…”

Efficient enzyme encapsulation inside sol-gel silica sheets prepared by poly-L-lysine as a catalyst

“…However, this method sometimes decreases the activity of encapsulated enzymes because the preparation of sol-gel silica gel needs an acid or a base as a catalyst. To avoid the reduction in the activity of the encapsulated enzymes, a method for preparing silica gel under mild conditions (e.g., ambient temperate and neutral pH) is needed [12,13].…”