Stimulus-Responsive Controlled Release System by Covalent Immobilization of an Enzyme into Mesoporous Silica Nanoparticles

Abstract

Mesoporous silica nanoparticles (MSN) have emerged as an attractive class of drug delivery carriers for therapeutic agents. Herein, we explored the covalent immobilization of proteins into MSN to generate a stimulus-responsive controlled release system. First, MSN were functionalized with thiol groups using (mercaptopropyl)-trimethoxysilane (MPTMS). Functionalization was verified by X-ray photoelectron spectroscopy (XP), Fourier-transform infrared (FTIR) spectroscopy, and dynamic light scattering. The model enzyme carbonic anhydrase (CA) was coupled to sulfosuccinimidyl 6-[3'(2-pyridyldithio)-propionamido]hexanoate (Sulfo-LC-SPDP) at a low ratio of 1:1 to prevent enzyme inactivation and subsequently covalently immobilized into MSN via thiol-disulfide interchange. The enzyme could be released from MSN with 10 mM glutathione which represents intra-cellular redox conditions while it remained bound to the MSN at extra-cellular redox conditions represented by 1 μM glutathione. The activity of the released enzyme was >80% demonstrating that the enzyme was still largely functional and active after immobilization and release. Human cervical cancer (HeLa) cells were incubated with the MSN-CA bioconjugates at various concentrations for 24 h and the data show good biocompatibility. In summary, we demonstrate the potential of MSN as potential drug delivery systems for proteins.

Tricalcium phosphate and tricalcium phosphate/polycaprolactone particulate composite for controlled release of protein

“…This type of release behavior, known as “pulsatile” release system, is a characteristic of energy dependent release process. Same release patterns are reported in different types of drugs and biomolecule delivery systems [24,25]. However, for larger particles of 550 nm, the burst release time increased from 1 h to 6 h, followed by continuous protein release up to 30-100% release.…”

“…As the layer number of adsorbed protein increased, this interaction becomes weaker and the initial release occurs due to the loosely bound distant protein layers release [2]. Although the release mechanisms need to be further understood, the current results show that the mechanisms are highly dependent on the particle size/ surface area, regardless of the adsorbed protein amount [24]. In addition, PCL-coating had no significant effect on the burst release in any of the used TCP materials.…”

Synthesis and characterization of Au nanocatalyst on modifed bentonite and silica and their applications for solvent free oxidation of cyclohexene with molecular oxygen

“…The FTIR spectra of modified bentonites as monolayer and bilayer ( Fig. 1b and 1c) display new peaks at 1473-1488, 1577, 2854-2927, and a peak at 2567 cm −1 was attributed to the thiol stretching vibration [18][19][20] which confirms the presence of the thiol groups (Supplementary data).…”

Controlled release and intracellular protein delivery from mesoporous silica nanoparticles

“…Additionally, in order to achieve cell or tissue specificity, the MSN surface can be decorated with cell directing moieties like peptides, antibodies or organic molecules. Recent studies on surface-functionalized MSNs have demonstrated controlled release of a variety of biogenic molecules like DNA, proteins, and pharmaceutical drugs [27,52,53]. In order to fine-tune the chemical properties of MSN, organic functionalization must be controlled.…”

“…Mendez et al improved the use of MSN as a protein drug carrier by first covalently immobilizing the model protein carbonic anhydrase on a thiolated surface. In this system, protein discharge occurred under intracellular conditions through the cleavage of the redox-sensitive disulfide bond that linked the protein and MSN [53].…”