Selective laser sintering of hydroxyapatite/poly-ε-caprolactone scaffolds

Abstract

Selective laser sintering (SLS) enables the fabrication of complex geometries with the intricate and controllable internal architecture required in the field of tissue engineering. In this study hydroxyapatite and poly--caprolactone, considered suitable for hard tissue engineering purposes, were used in a weight ratio of 30:70. The quality of the fabricated parts is influenced by various process parameters. Among them Four parameters, namely laser fill power, outline laser power, scan spacing and part orientation, were identified as important. These parameters were investigated according to a central composite design and a model of the effects of these parameters on the accuracy and mechanical properties of the fabricated parts was developed. The dimensions of the fabricated parts were strongly dependent on the manufacturing direction and scan spacing. Repeatability analysis shows that the fabricated features can be well reproduced. However, there were deviations from the nominal dimensions, with the features being larger than those designed. The compressive modulus and yield strength of the fabricated microstructures with a designed relative density of 0.33 varied between 0.6 and 2.3 and 0.1 and 0.6 MPa, respectively. The mechanical behavior was strongly dependent on the manufacturing direction.

Interaction of cell culture with composition effects on the mechanical properties of polycaprolactone-hydroxyapatite scaffolds fabricated via selective laser sintering (SLS)

“…It has been observed in previous experiments [29] that the effect of HA addition on the mechanical properties of the control samples is dependent on how strong the sintering is among the polymer particles. When sintering of the polymer results in good integrity, HA particles could limit molecular motion in PCL, resulting in increased compressive modulus.…”

“…In the current study the effect on cell response of two HA compositions (15 wt.% and 30 wt.%) with designed scaffold porosity is compared. Scaffold shapes and compositions were chosen based on a previous work [29].…”

Powder bed generation in integrated modelling of additive layer manufacturing of orthopaedic implants

“…There are limited published data on the compressive mechanical properties of PCL composites fabricated using SLS with different or near-full density in designed regions. However, it has been shown that loading ceramics up to 30 % with polymer composites can improve their mechanical properties [17]. FE modelling of mechanical properties can be seen as an effective tool in computational design and direct digital manufacture of patient-and site-specific composite tissue-engineering constructs with tailored properties [18].…”

Relationship between micro-porosity, water permeability and mechanical behavior in scaffolds for cartilage engineering

“…26 27 . PCL is a well used material for tissue engineering applications, with innumerous fabrication methods 28 29 such as for example selective laser sintering 30 , solvent casting films 31 32 , blends with PLA 33 15 , nanocomposite scaffolds 34 35 22 36 21 , electrospinning 37 38 39 40 , spin coating 41 , hyaluronic acid coating 42 43 or hot pressing technique 44 45 .…”