title: A mesoporous silica nanosphere-based drug delivery system using an electrically conducting polymer.
abstract: In this study, a mesoporous silica nanoparticle (MSN)-based nerve growth factor (NGF) delivery system has been successfully embedded within an electroactive polypyrrol (Ppy). The spherical particles with approximately 100 nm diameter possess a large surface-to-volume ratio for the entrapment of NGF into the pores of MSNs while retaining their bioactivity. Direct incorporation of MSN-NGF within Ppy was achieved during electrochemical polymerization. The loading amount and release profile of NGF from the composite was investigated by sandwich ELISA. The NGF incorporation can be controllable by varying particle concentration or by extending electrodeposition time. The morphology and chemical composition of the Ppy/MSN-NGF composite was evaluated by atomic force microscopy (AFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS). Optical and electron microscopy revealed a characteristic attachment of PC 12 cells and the outgrowth of their neurites when grown on the Ppy/MSN-NGF composite as a result of a sustained and controlled release of NGF. In order to observe the effectiveness of electrical stimulation, neurite extension of cells cultured on unstimulated and stimulated Ppy/MSN-NGF was compared. The NGF release in the presence of electrical stimulation promoted significantly greater neurite extension.
authors.affiliation: Center for Paralysis Research, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA. cho22@purdue.edu
authors.forename: Youngnam
authors.initials: Y
authors.lastname: Cho
authors.forename: Riyi
authors.initials: R
authors.lastname: Shi
authors.forename: Albena
authors.initials: A
authors.lastname: Ivanisevic
authors.forename: Richard
authors.initials: R
authors.lastname: Ben Borgens
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D016503:Drug Delivery Systems / Q000379:methods*; D004558:Electric Stimulation; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D008858:Microscopy, Phase-Contrast; D053761:Nanocomposites / Q000008:administration & dosage / Q000737:chemistry*; D054118:Nanospheres / Q000008:administration & dosage / Q000737:chemistry*; D020932:Nerve Growth Factor / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics; D016501:Neurites / Q000187:drug effects; D016716:PC12 Cells; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry*; D016062:Porosity; D011758:Pyrroles / Q000008:administration & dosage / Q000737:chemistry*; D051381:Rats; D012822:Silicon Dioxide / Q000008:administration & dosage / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; D012822:Silicon Dioxide; D020932:Nerve Growth Factor