DFT study of amino-functionalized silica for ampicillin adsorption

E. NOSEDA GRAU; G. ROMAN; A. DIAZ COMPAÑY; S. SIMONETTI

Congreso; Quantum Thermodynamics of Non-Equilibrium Systems; 2020

Nanocarriers to transport substances are hopeful places to increase the beneficial treatment of medical drugs. Ampicillin is an extensive-spectrum penicillin derivative used to treat several diseases and infections. Due to its great utility and small cost, ampicillin can be a model for a better analysis of the adsorption processes of drugs in novel ceramic materials such as functionalized silica. The adsorption of ampicillin drug on SiO2(001) and SiO2(111) hydroxylated surfaces have been studied by DFT calculations that have become an important tool to understand the behavior of materials. In this work, the improvement on adsorption when the system is functionalized with amino groups, are analyzed. The changes on adsorption of the pH dependence-ampicillin species are studied. Ampicillin molecule approaches on both surfaces via N and O atoms, doing more stable on SiO2(001). The stability depends on the H-bonds formed and this is conformity with the higher silanol density of SiO2(001) surface. The stability of ampicillin on SiO2(111) is favored when the surface is amino functionalized and the major adsorption energy is observed in presence of the deprotonated specie at basic pH. The changes are mainly related to the modification on HOMO-LUMO distribution comparing with the neutral specie and in consequence, the new interactions with the amino functionalized surface that contribute with new states in the DOS Fermi region.