Albumin and lysozyme interaction with sílica nanoparticles: thermodynamics and effect of the nanoparticles surface properties

Author(s)

Flávia Elisa Galdino

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2018-07-17

Examining board members

Watson Loh; Edvaldo Sabadini; Fernando Carlos Giacomelli

• Advisor: Mateus Borba Cardoso; Watson Loh

Abstract

Protein corona is a phenomenon characterized by the spontaneous and nonspecific adsorption of proteins on nanoparticles¿ surface. This protein shell influences on the action and efficiency of nanomaterials applied in nanomedicine. Particles functionalization with zwitterionic groups and polyethylene glycol (PEG) are two strategies to avoid the occurrence of this phenomenon. Considering these facts, this work¿s motivation is to synthesize silica nanoparticles and to study their interaction with different proteins (bovine serum albumin and lysozyme). For this, three types of silica nanoparticles were considered: I) unmodified (SiO2NPs), II) modified with zwitterionic sulfobetaine silane (SiO2NPs-SBS) and III) modified with polyethylene glycol (SiO2NPs-PEG). These nanoparticles were characterized by dynamic light scattering (DLS), zeta potential, microscopy, thermogravimetry (TGA) and nuclear magnetic resonance (NMR) measurements. The interaction studies were performed using DLS, ultraviolet absorption, circular dichroism (CD) and isothermal titration calorimetry (ITC). Three factors were considered in these studies: pH, temperature and ionic strength. The three nanoparticles presented a monomodal size distribution around 100 nm and approximately spherical shape. Surface modifications with SBS and PEG were confirmed by NMR and TGA techniques. Bovine serum albumin (BSA) was found to interact only with SiO2NPs. Therefore, for BSA, a negatively charged protein at physiological pH, modifications with SBS and PEG were efficient to avoid its adsorption. It was also observed that the interaction of BSA with SiO2NPs is controlled by enthalpy and that the factors ionic strength, pH and temperature influenced the results. Lysozyme, a positively charged protein at physiological pH, interacted with three nanoparticles of this project. Thus, the corona free property of SiO2NPs-SBS and SiO2NPs-PEG nanoparticles was not verified for this protein (AU)

• FAPESP's process: 16/11118-0 - Protein interaction with sílica nanoparticles: thermodynamics and effect of the nanoparticle surface properties
• Grantee: Flávia Elisa Galdino
• Support Opportunities: Scholarships in Brazil - Master