Adsorption of immunomodulatory proteins on silica nanoparticles

GIORGI, EXEQUIEL DAVID; DESIMONE, MARTÍN FEDERICO; DE MARZI, MAURICIO CESAR

Mar del Plata (Bs. As.)

Congreso; REUNIÓN ANUAL DE SOCIEDADES DE BIOCIENCIA 2019; 2019

SAIC-SAFE-SAB

Nanoparticles (NPs) are excellent platforms for protein immobilization due to their highsurface/volume ratio and they are under study as immunomodulation tools. Our objectiveis to analyze the adsorption of different proteins on silica NPs and evaluate their physicochemical properties and stability.Silica NPs (SiNPs) were synthesized according to the Stöber method. A portion of theseNPs were grafted with APTES to add amino groups to their surface, generatingSiNPsNH2. Size and shape of the NPs were analyzed by TEM and microimages wereprocessed by ImageJ software. NPs showed a spherical form, with a mean diameter of111 ± 11 nm. FTIR analysis revealed the SiO2 characteristic spectrum. Adsorptionisotherms of different proteins to both NPs were analyzed according to Langmuir andFreundlinch models. For TGF-β, the maximum adsorption capacity (MAC) was 0.0175mg/mg SiNPs with an adsorption efficiency (AE) of 60 % that fits Langmuir isothermmodel (R2= 0.9022) better than Freundlich isotherm model (R2= 0.8767). For IL-1β,MAC was 0.0526 mg/mg SiNPs with an efficiency of 86 %. Both proteins showed loweradsorption capacity and efficiency over SiNPsNH2 than over SiNPs. IL-1β adsorption onNPsSiO2 fit only Freundlich model (R2= 0.9350). BSA immobilization on NPsSiO2 has aMAC of 0.2 mg/mg SiNPs with an AE of 76 %. Same results were obtained withSiNPsNH2. All NPs-protein complexes were stable at 4°C and pH 7.4 with a slight proteinrelease after a wash with PBS. Human monocytic leukemia cells (THP-1) were culturedwith SiNPs and SiNPs/TGF-β for 24-96 h. A decrease on the cell metabolic activity inpresence of TGF-β alone was observed (P