Development and structural evaluation of poly(lactic acid) based knitted scaffold for human urinary bladder reconstruction

Abstract

<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="metricconverter"> Knitted scaffolds of poly(lactic acid) (PLA) filament spun by dry-jet-wet technique have been developed for human urinary bladder reconstruction. Three different types of samples are prepared by varying the number of ply in the PLA yarn. Flexural rigidity of PLA monofilament is found to be dependent on draw ratio. It decreases from 16.22×10^-7 kg m⁴ to 2.74×10^-7kg m⁴ as the draw ratio increases from 2 to 10. The performance of the developed structures is evaluated by ball bursting technique on a tensile tester. It is observed that the knitted structure with 8 ply yarn has bursting strength of 53.7 kg with 2.5 cm extension. The cyclic loading of knitted structure has been carried out at the load half of the bursting loads. It is found that the structure gets permanently set after 5 cycles of loading. Porosity of the knitted fabric is determined by ratio of voids volume to that of the total volume of knitted fabric. The knitted structure with 8 ply yarn has 80% porosity. Pore size of the knitted structures is determined by optical microscope. The <i style="">in vitro</i> degradation of the PLA knittings at different <i>p</i>H (4.6, 7.4 and 8.0) has been carried out for a period of 20 weeks. The surface morphology was studied by scanning electron microscopy. A severe degradation of sample is observed at <i>p</i>H 4.6. </smarttagtype>