Reticulacao de pericardio bovino com glutaraldeido: efeitos da temperatura , tempo de reação e concentração. / Crossliking of bovine pericardium with glutaraldehyde:effect of temperature, reaction time and concentration.

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

The object of this work was the development of a new procedure for homogeneous crosslinking of bovine pericardium (BP), to improve its properties when used for cardiac valves confection. A sequential treatment with increasing concentrations of glutaraldehyde (GA), from 0.0010/0to 0.5%, was used in temperatures ranging from 5°C to 45°C and reaction times ranging from 5 to 90 min. Shrinkage temperature (Ts) results showed that non-sequential and sequential treatments produced heterogeneous crosslinking of bovine pericardium, mainly for lower concentrations of glutaraldehyde (0.001%). The heterogeneity is less perceptible for greater concentrations of glutaraldehyde, specially in the sequential treatment, suggesting better quality of crosslinking reaction. Best results were obtained for the sequential treatment at 45°C, for 90 min and 0.1% of glutaraldehyde, with Ts values (≅ 90°C) very similar to those found for higher glutaraldehyde concentration (0.5%). In these conditions, the smaller values of enzymatic hydrolysis were obtained (collagenase = 3.80/0and tripsin = 1.90/0).This behavior, at 45°C, may be associated to the presence of higher monomeric glutaraldehyde concentration, more efficient in the crosslinking promotion, and to the exposition of a great number of reaction sites in bovine pericardium matrix. The results of enzymatic hidrolysis with collagenase and tripsin, confirmed that sequential treatment is more efficient, specially knowing that: a) the GA for BP reaction involved e-amino groups of lisin: b) the tripsin alone act over peptides bonds involving lisin with free e-amino groups. Then, it is possible to predict that a great number of e-amino groups were blocked, not permitting enzimatic action, showing that the materials were more crosslinked. Mechanical tests for materials treated as above demonstrated that for sequential treatment the values are within the acceptable range for cardiac valves construction.

ASSUNTO(S)

válvulas cardíacas cardiac valves glutaraldehyde pericárdio bovino bovine pericardium glutaraldeído

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