title: Delivery of chemotropic proteins and improvement of dopaminergic neuron outgrowth through a thixotropic hybrid nano-gel.
abstract: Chemotropic proteins guide neuronal projections to their final target during embryo development and are useful to guide axons of neurons used in transplantation therapies. Site-specific delivery of the proteins however is needed for their application in the brain to avoid degradation and pleiotropic affects. In the present study we report the use of Poly (ethylene glycol)-Silica (PEG-Si) nanocomposite gel with thixotropic properties that make it injectable and suitable for delivery of the chemotropic protein semaphorin 3A. PEG-Si gel forms a functional gradient of semaphorin that enhances axon outgrowth of dopaminergic neurons from rat embryos or differentiated from stem cells in culture. It is not cytotoxic and its properties allowed its injection into the striatum without inflammatory response in the short term. Long term implantation however led to an increase in macrophages and glial cells. The inflammatory response could have resulted from non-degraded silica particles, as observed in biodegradation assays.
authors: Instituto de Ciencias de la Salud, Universidad Veracruzana, Xalapa, VER, México. elisatammx@gmail.com
authors: Elisa
authors: E
authors: Tamariz
authors: Andrew C A
authors: AC
authors: Wan
authors: Y Shona
authors: YS
authors: Pek
authors: Magda
authors: M
authors: Giordano
authors: Genoveva
authors: G
authors: Hernández-Padrón
authors: Alfredo
authors: A
authors: Varela-Echavarría
authors: Iván
authors: I
authors: Velasco
authors: Víctor M
authors: VM
authors: Castaño
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D004298:Dopamine / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism; D049329:Nanostructures; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D011092:Polyethylene Glycols; D051381:Rats; D011994:Recombinant Proteins / Q000008:administration & dosage; D040121:Semaphorin-3A / Q000008:administration & dosage; D013059:Spectrum Analysis, Raman
chemical_list: D001672:Biocompatible Materials; D011994:Recombinant Proteins; C488218:Sema3a protein, rat; D040121:Semaphorin-3A; D011092:Polyethylene Glycols; D004298:Dopamine