Mesoporous silica is a versatile carrier for biomolecules due to its stability, low toxicity, and ability to be functionalized with a variety of molecules and polymers. The porous structure with hundreds of void channels can absorb/ encapsulate reasonably large amounts of biomolecules and the distinctive properties, such as high surface area, large pore volume, and tuneable pore size with a narrow distribution make them readily suitable for various controlled release applications. The adsorption of protein on solid surfaces is a common yet complicated phenomenon due to the complex behaviour of the macromolecules during this process. Hence, it is important to understand; why and how these biomolecules adsorb, the behaviour of adsorbed proteins either as individual molecules or in an ensemble, the influence of adsorption on the protein’s biological function and, if there is a general mechanistic rule for the adsorption process.
In general, the immobilisation of biomolecules onto solid surfaces is often considered irreversible, which can be addressed by the use of surface-active substances or large polymers as displacers as long as they do not affect the protein conformation during or after desorption. Displacer molecules such as surfactants encourage desorption of the macromolecules by an exchange mechanism where the attached protein is competitively substituted from the adsorbent surface in the favour of immobilisation of the smaller molecules.
This presentation discusses the possible use of mesoporous silica as a drug delivery carrier for macromolecules without compromising their biological activity by establishing the required ‘ideal parameters’ for surface immobilisation. Along with this, the optimal parameters to allow maximum desorption, especially the role of displacer will also be discussed.
Vivek Trivedi, Lecturer in Drug Delivery, Medway School of Pharmacy, University of Kent