Synthesis and characterization of mesoporous silicas with dendritic and spongy-like structures: potential supports for human lactate dehydrogenase-based microreactors aimed at anticancer inhibitor screening

Mesoporous silica are versatile materials with wide-ranging potential. Notably, they excel as enzyme supports. This work examines the influence of three distinct siliceous mesoporous materials used as supports for the enzyme human lactate dehydrogenase (hLDH-A). Drugs with inhibition effects have recently shown favorable effects on diminishing the proliferation of cancerous cells. The ultimate goal of this research is to produce a stable and effective biocatalyst suitable for being employed in a microreactor for the screening of hLDH-A inhibitors. The synthesized mesoporous silica exhibited distinctive structural features, including a quasi-mesocellular network, bent-channels structure, and a dendritic geometry with radial symmetry, as evidenced by FESEM and HR-TEM. These materials were functionalized with amino and aldehyde groups to covalently immobilize hLDH-A. Characterization of both pristine and functionalized materials involved a comprehensive examination of their physico-chemical properties. The CO dosing revealed Brønsted acidity characteristic of mesoporous silica, while FT-IR spectroscopy and N2 physisorption at 77 K confirmed their successful functionalization. Enzyme immobilization on the functionalized supports, performed with stabilizing agents such as PEG (0.05 mg/ml) or trehalose (300 mM), produced promising results. The immobilization yield consistently exceeded 80 %, with retained activity reaching values as high as 15 %. The immobilization of the enzyme on mesoporous silica increased the stability of hLDH-A against alkaline and organic solutions. These findings hold significance for those exploring siliceous porous supports for enzyme immobilization, paving the way for the development of stable and active biocatalysts.