Synthesis and characterization of poly(L-lactic acid) membranes: studies in vivo and in vitro.

The use of biodegradable polyesters as temporary structural supports in the recuperation of damaged live tissue is a promising area of research. Poly(L-lactic acid) (PLLA) membranes can act as a support for cell fixation and growth or as a barrier against soft tissues invasion in recuperating bone tissues. In this work, five different types of PLLA membranes, which varied in their polymer-solvent ratio and their content of plasticizer were studied. For the study in vivo, 6 mm diameter disks were inserted subcutaneously in the dorsal region of 15 Wistar rats, and the reactions on rats were studied 15 days later. In another series of experiments the samples were immersed in phosphate buffer, pH 7.4 at 37 degrees C, for 30 days. Membranes without plasticizer were morphologically dense and did not allow cell invasion nor tissue adherence, in contrast to membranes with plasticizer. While porosity enhanced cell fixation and growth, it made the membrane more fragile mechanically when compared to membranes without pores.