Protein encapsulation in SBA-15 with expanded pores

This work reports the encapsulation of proteins with different molecular weights into SBA-15 ordered mesoporous silica, a potential immunological adjuvant. The Human Gammaglobulin G (HGG) and Bovine Serum Albumin (BSA) proteins were incorporated into the mesoporous silica with expanded pores. A structure swelling agent, triisopropylbenzene (TIPB), was used in the synthesis process, promoting an increase of the average pore diameter and a more disordered pore network, as revealed by nitrogen adsorption isotherm (NAI) and small angle X-ray scattering (SAXS) data. SAXS measurements were also performed to obtain the overall size of the studied proteins. The results showed that both proteins have dimensions that would allow their encapsulation inside the pores of SBA-15. The HGG and BSA proteins were dissolved in phosphate buffered saline (PBS) solutions before encapsulation. It was evidenced the filling of the micropores by the PBS solution and a larger variation in pore volume and surface area for the material with higher mean pore diameter, which was also confirmed by the modeling of SAXS data. It was not observed any significant difference in the SAXS and NAI results of both proteins, indicating that the immunogens could be encapsulated in the silica macroporosity, obstructing the mesopore entrances. (C) 2016 Elsevier Inc. All rights reserved.