Adsorption of immunomodulatory proteins on silica nanoparticles

GIORGI, EXEQUIEL; DE MARZI MAURICIO C; DESIMONE MARTIN

Mar del Plata

Congreso; SAIC, SAFE, SAB, SAP 2019. Participan AACYTAL y NANOMED-AR.; 2019

SAIC, SAFE, SAB y SAP

Nanoparticles (NPs) are excellent platforms for protein immobilization due to their high surface/volume ratio and they are under study as immunomodulation tools. Our objective is to analyze the adsorption of different proteins on silica NPs and evaluate their physico-chemical properties and stability.Silica NPs (SiNPs) were synthesized according to the Stöber method. A portion of these NPs were grafted with APTES to add amino groups to their surface, generating SiNPsNH2. Size and shape of the NPs were analyzed by TEM and microimages were processed by ImageJ software. NPs showed a spherical form, with a mean diameter of 111 ± 11 nm. FTIR analysis revealed the SiO2 characteristic spectrum. Adsorption isotherms of different proteins to both NPs were analyzed according to Langmuir and Freundlinch models. For TGF-β, the maximum adsorption capacity (MAC) was 0.0175 mg/mg SiNPs with an adsorption efficiency (AE) of 60 % that fits Langmuir isotherm model (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 lower adsorption capacity and efficiency over SiNPsNH2 than over SiNPs. IL-1β adsorption on NPsSiO2 fit only Freundlich model (R2= 0.9350). BSA immobilization on NPsSiO2 has a MAC of 0.2 mg/mg SiNPs with an AE of 76 %. Same results were obtained with SiNPsNH2. All NPs-protein complexes were stable at 4°C and pH 7.4 with a slight protein release after a wash with PBS. Human monocytic leukemia cells (THP-1) were cultured with SiNPs and SiNPs/TGF-β for 24-96 h. A decrease on the cell metabolic activity in presence of TGF-β alone was observed (P