RESUMO
The interaction of murine embryonic cortical neurons on randomly orientated electrospun scaffolds of poly(L-lactide) (P(L)LA) and poly(lactide-co-glycolide) (PLGA) is investigated in this study. The scaffolds were surface treated with different concentrations of KOH to partially hydrolyze the surface and therefore change the surface tension. Hydrophilicity did not significantly influence the number of primary and secondary branches; however, it had a considerable effect on neurite extension. For scaffolds with surface tensions of 40-47 dyn cm(-1) there was a significantly greater overall neurite length for both the primary and secondary branches compared with more hydrophilic scaffolds. Another major finding of this work was that the interfibre distance influenced how the neurites extended. When the interfibre distance was greater than approximately 15 microm the neurites followed the fibres and avoided regions of very high fibre density. At interfibre distances less than approximately 15 microm, the neurites traversed between the fibres. Therefore, this study provided little evidence that contact guidance was the dominating cue in directing neurite extension, instead inferring that chemical cues, possibly from adjacent neurons had induced directional change.
Assuntos
Córtex Cerebral/embriologia , Regeneração Tecidual Guiada/métodos , Ácido Láctico/química , Nanoestruturas/química , Neurônios/citologia , Neurônios/fisiologia , Ácido Poliglicólico/química , Polímeros/química , Engenharia Tecidual/métodos , Animais , Materiais Biocompatíveis/química , Técnicas de Cultura de Células/métodos , Crescimento Celular , Células Cultivadas , Córtex Cerebral/citologia , Córtex Cerebral/fisiologia , Regeneração Tecidual Guiada/instrumentação , Camundongos , Camundongos Endogâmicos C57BL , Nanoestruturas/ultraestrutura , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Propriedades de SuperfícieRESUMO
The aim of this study was to investigate the interaction of mouse embryonic cortical neurons on P(L)LA and PLGA substrates, which were partially hydrolysed using potassium hydroxide (KOH). The chemical and topographical properties of the surfaces were characterized, and it was discovered that there was a decrease in the hydrophilicity for the P(L)LA with increasing concentration of KOH. This was due to chemical modifications to the surfaces of the substrates. Alternatively for the PLGA substrate, only the 0.1 M KOH treated sample had a significantly different hydrophilicity highlighting that surface erosion resulted at higher concentrations. The morphology of the neurons grown on the two substrates were compared to poly(D)lysine (positive control). The neurons formed colonies on all of the substrates, but were dramatically reduced in size in the case of the 0.1 M KOH treated substrates. This finding was attributed to the increases in cell spreading and the size of the cells, as they were larger, more elongated and bipolar like those on the positive control. However, there was a significant decrease in the total number of live cells per unit area. Therefore, on these materials when there was increased cellular spreading there was significantly higher cell death. Furthermore, unlike the 0, 0.2, and 0.4 M KOH treated substrates, there was an absence of large bundles of axons that extended between colonies on the 0.1 M sample, instead exhibiting short axons that grew in free space.
Assuntos
Córtex Cerebral/embriologia , Neurônios/fisiologia , Animais , Materiais Biocompatíveis , Técnicas de Cultura de Células , Divisão Celular , Membrana Celular/fisiologia , Membrana Celular/ultraestrutura , Concentração de Íons de Hidrogênio , Hidróxidos , Ácido Láctico , Camundongos , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Neurônios/citologia , Poliésteres , Ácido Poliglicólico , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Polímeros , Compostos de Potássio , Propriedades de SuperfícieRESUMO
The aim of this study was to determine the ability of various poly(alpha-hydroxy esters) to support the in vitro propagation of murine embryonic stem (ES) cells in an undifferentiated state. To this end, ES cell colonization, growth and Oct-4 immunoreactivity following a 48 h culture period upon poly((D,L)-lactide), poly((L)-lactide), poly(glycolide) and poly((D,L)-lactide-co-glycolide) (PLGA) were assessed. By the analysis of live and dead cell number indices and Oct-4 immunoreactivity, ES cell colonization rate during a 48 h culture period was found to be significantly greater on PLGA compared to all the other unmodified poly(alpha-hydroxy esters) tested. Surface treatment of all polymers with 0.1m potassium hydroxide revealed a significant increase in ES cell live numbers when compared to all unmodified polymers, thus revealing a correlation between polymer content, hydrophilicity and colonization rate. These data suggest that surface treated poly(alpha-hydroxy esters) may be employed for ES cell scale up procedures and in tissue engineering applications requiring the colonization of scaffolds by ES cells in an undifferentiated state. According to such applications, once the designated scaffold has been colonized, ES cell directed differentiation into the desired and fully differentiated, functional adult tissue may then be effected.
