(609c) Amine-Functionalized Sba-15 on Protein Delivery: Adsorption, Release and Stability of Bovine Serum Albumin

In recent years, application of mesoporous silica materials to controlled drug delivery has attracted much interest due to their high surface area, tunable uniform large pore size, and chemically-modifiable surface [1,2]. The aim of the present study is to explore the potential of applying mesoporous silica materials to protein delivery system by investigating their influence on adsorption, release and stability of model protein drug. Mesoporous siliceous SBA-15 materials were functionalized with amine groups either by post-synthesis or by one-pot synthesis, and loaded with bovine serum albumin (BSA) as the model protein drug [3]. The effects of the content of the amine groups, pore size and the pH value of BSA buffer solutions on the adsorption of BSA on amine-functionalized SBA-15 have been systematically studied. The results show that higher BSA loadings could be obtained on amine-functionalized SBA-15 which has higher amine group content, larger pore size and at the pH value near the isoelectric region of BSA. FTIR and Raman spectra characterising the BSA-loaded samples show intense peaks at 1600-1700 and 1500-1600 cm-1 due to the presence of the respective amide I and amide II bands of the adsorbed BSA, indicating the presence of a high loading amount of BSA in the amine-functionalized SBA-15. After being loaded with BSA and freeze-dried, the resulting materials were then soaked with phosphate-buffered saline solutions at pH 7.4 for in vitro release studies. The release profiles show that the release rates of BSA from amine-functionalized SBA-15 could be controlled by the content of the surface amine group and the pore size of SBA-15. Circular dichroism analysis used in this study to investigate the conformational change of BSA before being adsorbed and after being released from the amine-functionalized SBA-15 shows that BSA conformation can be influenced by different functionalization methods and adsorption conditions. Interestingly, the integrity of the released BSA structure could be well maintained under certain selected adsorption and release conditions, showing that amine-functionalized SBA-15 is a potential matrix for protein delivery.

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