Reinforcement of poly-l-lactic acid electrospun membranes with strontium borosilicate bioactive glasses for bone tissue engineering

Abstract

Herein, for the first time, we combined poly-L-lactic acid (PLLA) with a strontium borosilicate bioactive glass (BBG-Sr) using electrospinning to fabricate a composite bioactive PLLA membrane loaded with 10% (w/w) of BBG-Sr glass particles (PLLA-BBG-Sr). The composites were characterised by scanning electron microscopy (SEM) and microcomputer tomography (l-CT), and the results showed that we successfully fabricated smooth and uniform fibres (1-3 lm in width) with a homogeneous distribution of BBG-Sr microparticles (<45 lm). Degradation studies (in phosphate buffered saline) demonstrated that the incorporation of BBG-Sr glass particles into the PLLA membranes increased their degradability and water uptake with a continuous release of cations. The addition of BBG-Sr glass particles enhanced the membrane's mechanical properties (69% higher Young modulus and 36% higher tensile strength). Furthermore, cellular in vitro evaluation using bone marrow-derived mesenchymal stem cells (BM-MSCs) demonstrated that PLLA-BBG-Sr membranes promoted the osteogenic differentiation of the cells as demonstrated by increased alkaline phosphatase activity and up-regulated osteogenic gene expression (Alpl, Sp7 and Bglap) in relation to PLLA alone. These results strongly suggest that the composite PLLA membranes reinforced with the BBG-Sr glass particles have potential as an effective biomaterial capable of promoting bone regeneration. Statement of Significance PLLA membranes were reinforced with 10% (w/w) of strontium-bioactive borosilicate glass microparticles, and their capacity to induce the osteogenic differentiation of bone marrow mesenchymal stem cells (BM-MSCs) was evaluated. These membranes presented an increased: degradability, water uptake, Young modulus and tensile strength. We also demonstrated that these membranes are non-cytotoxic and promote the attachment of BM-MSCs. The addition of the glass microparticles into the PLLA membranes promoted the increase of ALP activity (under osteogenic conditions), as well as the BM-MSCs osteogenic differentiation as shown by the upregulation of Alpl, Sp7 and Bglap gene expression. Overall, we demonstrated that the reinforcement of PLLA with glass microparticles results in a biomaterial with the appropriate properties for the regeneration of bone tissue.

Piezoelectric materials as stimulatory biomedical materials and scaffolds for bone repair

“…Polymer matrix composites (PMCs) allow for combination of manufacturing flexibility and the processing of otherwise brittle ceramics with higher piezoelectric constants to complex forms. PLLA based composites have extensively been studied for application in the field of bone tissue engineering [161,162], as reviewed in [159]. Though piezoelectricity has been observed in electrospun fibre mats based on PLLA [148,[163][164][165], the focus has been to improve the suitability of the scaffolds for desired application under static environment without the mention of the contribution of piezoelectric properties of fillers or PLLA itself [166,167].…”

Electrospun poly(d,l‐lactide)/gelatin/glass‐ceramics tricomponent nanofibrous scaffold for bone tissue engineering

“…Starting from first composition of 45S5 Bioglass first developed by Hench (Hench, Splinter, Allen, & Greenlee, ), which was mainly composed of silicate network incorporating sodium, calcium, and phosphorus, nowadays other bioactive glass compositions with additional elements were studied. For example fluorine, magnesium, strontium, silver, zinc, copper, potassium, niobium, or boron were added and tested for their bioactivity and properties such as osteoinduction, angiogenesis, and antibacterical action (Bejarano, Detsch, Boccaccini, & Palza, ; De Bonis et al, ; Fernandes et al, ; Haimi et al, ; Hoppe, Guldal, & Boccaccini, ). Also modified microparticles of silicon‐doped hydroxyapatite were employed in combination with PCL to form composite electrospun scaffold.…”

Multi-layer Scaffolds of Poly(caprolactone), Poly(glycerol sebacate) and Bioactive Glasses Manufactured by Combined 3D Printing and Electrospinning

“…The scaffolds without BGs and with 5 wt% BGs showed a similar degradation profile with a weight loss of 6.5% (3D-ES PCL-PGS) and 7.0% (3D-ES PCL-PGS-5BGs) after 21 days; while, in the same time frame, the 3D-ES PCL-PGS-10BGs samples exhibited a 9.8% weight loss. The degradation was initiated by the hydrolysis of PGS and dissolution of the BGs microparticles [38][39][40][41][42]. The release of unreacted carboxylic acid groups of PGS and those formed by the cleavage of PGS ester linkages caused acidification of the PBS medium [13,23]: pH 6.0 after 21 days.…”