Fabrication of PLLA nanofibers as synthetic grafts for anterior cruciate ligament reconstruction

Abstract

Hypertension and flexion in knee will cause anterior cruciate ligament (ACL) injury resulting in rotational instability of the knee. Synthetic grafts made from Polylactice acid are efficient in terms of biomechanical compatibility and easy manufacturing method makes PLLA suitable for ACL replacement. PLLA nanofibre is synthesized by mixing the polymer with chloroform in 8:100 proportions and the fibres are drawn using electro spinning technique. Mechanical and Characterization testing’s such as AFM, XRD and FTIR where done on the fibre. Polymer concentrations of 5- 10 wt% are the appropriate range to produce bead free fibres. The Needle-to-collector tip distance of 12.5cm, electro spinning voltage of 18kV and the concentration 8wt% should be maintained to synthesis fibres with desired characteristics. Tensile strength (40.68 ± 2.99MPa)and flexion strength (91 ± 3.55 MPa) of the PLLA nanofibre closely matches the natural ACL. Atomic Force Microscopy examination of the fibre shows smooth morphology with no bead formation and the length obtained is in the range of 3.4µm-3.8µm. XRD results shows 2 degree intensity drop which dictates that the fibre is devoid of crystals which is necessary for tissue engineering applications. the absorbance peaks in the FTIR shows the wavelength corresponding to of three main functional groups namely Carbonyl group (C=O), Alkenes (C=C), Hydroxyl group (-OH). The PLLA polymer when mixed with chloroform, the hydroxyl group gets added to the ring structure of the polymer. The integrity of the fiber also depends on the interatomic bonding between the solvent and the PLLA polymer.