Long‐term evaluation of porous poly(ϵ‐caprolactone‐co‐L‐lactide) as a bone‐filling material

Abstract

Porous poly(epsilon-caprolactone-co-L-lactide) (P(CL-co-LA, wt % ca. 5/95) sponges were prepared, coated biomimetically with CaP/apatite, and implanted with noncoated control sponges into rat femur cortical defects and dorsal subcutaneous space. The implants were inspected histologically at 2, 4, and 33 weeks after the operation. All implants were filled with fibrovascular tissue within 4 weeks. The femur implants were partially ossified with compact bone, which in the CaP-coated sponges was less mature and more fragmented. Approximately equal amounts of bone were observed in both types of implants. The polymer induced a mild inflammatory reaction with foreign body giant cells but no accumulation of fluid. Degradation of the polymer was slow; most of it was found intact at 33 weeks in histological samples. Nondegraded polymer seems to prevent complete ossification. Cultured osteoblasts proliferated well on apatite-coated material, whereas only a few cells were seen on noncoated material. Thus CaP/apatite coating helped the attachment of osteoblasts in cell cultures but did not offer any advantage in bone formation over noncoated material in vivo. We conclude that a shorter degradation time of P(CL-co-LA) is needed to create an optimal implant. Furthermore, in vivo experiments seem to be necessary for the estimation of osteopromotive properties of a biomaterial.

Polylactic acid fibre-reinforced polycaprolactone scaffolds for bone tissue engineering

“…Among biomedical polymers, PCL is characterized by an extended resorption time (up to 2 years as a bulk), while PLLA fibres are degraded at a higher rate: both have good compatibility [3,40]. The combination of polymers with different degradation kinetics in such a way may be an interesting approach to obtain scaffolds with controlled degradation rates according to the specific biomedical application.…”

Bone tissue engineering: A review in bone biomimetics and drug delivery strategies

“…A literature review indicates that a pore size in the range of 10-400 lm may provide enough nutrient and osteoblast cellular infusion, while maintaining structural integrity. [185][186][187][188][189][190] A wide variety of fabrication techniques have been investigated to recreate the microscale porosity and special organization of native bone. Some examples of well developed techniques include: micromachining, photolithography, calcium-phosphate sintering, rapid prototyping, melt extrusion, salt leaching, emulsion templating, phase separation, fiber bonding, membrane lamination, and polymer demixing.…”

Engineering functionally graded tissue engineering scaffolds

“…Enzymatic degradation (Ren et al, 2005) Synthetic polymers: Poly(L-lactic acid) (PLLA) 2-12 months Hydrolytic mechanism (Yang et al, 2001) Poly(glycolic acid) (PGA) 4-6 months Hydrolytic mechanism (Yang et al, 2001) Poly(caprolactone) (PCL) 1-2 years Hydrolytic mechanism (Engelberg and Kohn, 1991;Holmbom et al, 2005) Bioceramics:…”