Preparation of Cotton-Wool-Like Poly(lactic acid)-Based Composites Consisting of Core-Shell-Type Fibers

Abstract

In previous works, we reported the fabrication of cotton-wool-like composites consisting of siloxane-doped vaterite and poly(l-lactic acid) (SiVPCs). Various irregularly shaped bone voids can be filled with the composite, which effectively supplies calcium and silicate ions, enhancing the bone formation by stimulating the cells. The composites, however, were brittle and showed an initial burst release of ions. In the present work, to improve the mechanical flexibility and ion release, the composite fiber was coated with a soft, thin layer consisting of poly(d,l-lactic-co-glycolic acid) (PLGA). A coaxial electrospinning technique was used to prepare a cotton-wool-like material comprising “core-shell”-type fibers with a diameter of ~12 µm. The fibers, which consisted of SiVPC coated with a ~2-µm-thick PLGA layer, were mechanically flexible; even under a uniaxial compressive load of 1.5 kPa, the cotton-wool-like material did not exhibit fracture of the fibers and, after removing the load, showed a ~60% recovery. In Tris buffer solution, the initial burst release of calcium and silicate ions from the “core-shell”-type fibers was effectively controlled, and the ions were slowly released after one day. Thus, the mechanical flexibility and ion-release behavior of the composites were drastically improved by the thin PLGA coating.

Oriented siloxane-containing vaterite/poly(lactic acid) composite scaffolds for controlling osteoblast alignment and proliferation

“…In vivo, newly formed bone was observed in 4 weeks, and the defect was covered in 12 weeks. Kasuga et al reported cotton-like SiV/PLLA composites prepared by an electrospinning method, and the composites showed excellent bioactivity and ease of handling for bone-filling surgery [25,26].…”

Hybrid core–shell scaffolds for bone tissue engineering

“…SEM images of fractured (3:3) coaxial fibres (figure 3(a)) did not show an exposed core layer as some studies suggest [17][18][19], however, it did show a few hollow fibres. TEM cross-sectional images show clearly the core and shell configuration and the surface porosity, but no mixing between the layers.…”

Tailoring the delivery of therapeutic ions from bioactive scaffolds while inhibiting their apatite nucleation: a coaxial electrospinning strategy for soft tissue regeneration

“…A coaxial electrospinning setup was used to create a polymeric core-shell non-woven fabric within which the inorganic particles were loaded in the core of the bres protected by a polymeric shell. 20 One important criterion of this engineered system is that the shell layer must uptake water from the surrounding body uid in order to trigger the hydrolytic degradation of the inorganic particles and subsequent diffusion of the therapeutic ions in the media.…”

“…[25][26][27][28] Poly(D,L-lactide-co-glycolide) (PLGA) was selected has an outer layer for its ability to uptake water and therefore allowing the hydrolytic degradation of the enclosed SiV particles. 20,29,30 The effect of the relative diameter of the inner core to the size of the PLGA shell on the mechanical properties, dissolution behaviour, and apatite nucleation was investigated.…”