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Description
Introduction
Extracellular matrix (ECM) of hard tissues in human body has a specific composition combining organic and inorganic fractions that determines their properties and function. Therefore, designing scaffolds for bone tissue regeneration we should consider hybrid materials providing proper mechanical and structural support. The focus of current study were scaffolds based on poly(3-hydroxybutyric acid-co-3-hydrovaleric acid) (PHBV) enriched with hydroxyapatite (HA) nanoparticles, prepared by blend electrospinning [1].
Methodology
Two types of electrospun scaffolds were prepared using an EC-DIG device (IME Technologies), namely PHBV and PHBV+HA. For both samples the applied voltage during electrospinning was 17 kV and needle was positioned at distance of 20 cm to the collector. Morphology of as received fibers was studied by scanning electron microscopy (SEM, Meriln, Zeiss) followed by focused ion beam (FIB) sectioning to expose fibers interior. The successful incorporation of HA particles into PHBV fibers was confirmed by energy dispersive X-ray spectroscopy (EDS, Brucker). Finally, in vitro studies with MG-63 cells were performed up to 7 days of incubation. Cell viability and proliferation was evaluated using Cell Titer-Blue® Assay and cell morphology was studied by confocal and SEM imaging.
Results and discussion
Smooth fibers with random orientation and average diameter of 2.92 ± 0.28 μm were obtained from electrospinng of PHBV solution. Addition of HA particles resulted in porous fibers formation with increased diameter of 3.76 ± 0.37 μm. Ceramic particles were present both inside fibers as well as exposed on their surface.
Based on proliferation test and confocal imaging results, the higher cell number was observed on hybrid PHBV+HA scaffolds compared with solely PHBV fibers. Especially significant boost in cell proliferation was observed between 4th and 7th day of incubation. Microscopy imaging enabled to visualize cells elongation, filopodia formation and penetration in depth on both type of scaffolds. Importantly, PHBV+HA fibers due to particles on their surface provided more anchoring points for cells spreading, therefore, higher cell number with longer filopodia were observed for hybrid scaffolds.
Conclusions
In this study we showed that by simple approach of blend electrospinning combining PHBV and HA we could obtain scaffolds improving bone cells proliferation and growth. Therefore, we proved that such composite scaffolds are a very promising material for bone tissue regeneration.
Acknowledgement
This study was financially supported by the grant PRELUDIUM15, No. 2018/29/N/ST8/02032, financed by the National Science Center in Poland.
References
[1] Karbowniczek, J.E. et al. Front. bioeng. biotechnol. 9, 1-13 (2021).
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