title: 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 (XPS), 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 intracellular redox conditions, while it remained bound to the MSN at extracellular 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 drug delivery systems for proteins.
authors.affiliation: Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan, PR 00931-3346, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Méndez
authors.forename: Alina
authors.initials: A
authors.lastname: Monteagudo
authors.forename: Kai
authors.initials: K
authors.lastname: Griebenow
mesh_terms: D000818:Animals; D055162:Biocatalysis; D002256:Carbonic Anhydrases / Q000737:chemistry* / Q000378:metabolism*; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D003692:Delayed-Action Preparations; D004337:Drug Carriers / Q000737:chemistry* / Q000633:toxicity; D004789:Enzyme Activation; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D016062:Porosity; D011487:Protein Conformation; D012822:Silicon Dioxide / Q000737:chemistry*; D013388:Succinimides / Q000737:chemistry
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004800:Enzymes, Immobilized; D013388:Succinimides; C018151:N-succinimidyl 3-(2-pyridyldithio)propionate; D012822:Silicon Dioxide; D002256:Carbonic Anhydrases