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Biomaterial-Based Nanocomposite for Osteogenic Repurposing of Doxycycline

Authors El-Habashy S, Eltaher H, Gaballah A, Mehanna R, El-Kamel AH

Received 20 December 2020

Accepted for publication 20 January 2021

Published 12 February 2021 Volume 2021:16 Pages 1103—1126


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 4

Editor who approved publication: Prof. Dr. Thomas J. Webster

Salma El-Habashy,1 Hoda Eltaher,1 Ahmed Gaballah,2 Radwa Mehanna,3,4 Amal H El-Kamel1

1Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, 21521, Egypt; 2Microbiology Department, Medical Research Institute, Alexandria University, Alexandria, 21561, Egypt; 3Medical Physiology Department, Faculty of Medicine, Alexandria University, Alexandria, 21131, Egypt; 4Center of Excellence for Research in Regenerative Medicine and Applications CERRMA, Faculty of Medicine, Alexandria University, Alexandria, 21131, Egypt

Correspondence: Amal H El-Kamel
Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, 1 Khartoum Square, Azarita, PO Box 21521, Alexandria, Egypt
Tel +20-10-0508 0510

Background: Besides its antimicrobial action, doxycycline (DX) has lately been repurposed as a small-molecule drug for osteogenic purposes. However, osteogenic DX application is impeded by its dose-dependent cytotoxicity. Further, high-dose DX impairs cell differentiation and mineralization.
Purpose: Integrating DX into a biomaterial-based delivery system that can control its release would not only ameliorate its cytotoxic actions but also augment its osteogenic activity. In this work, we managed to engineer novel composite DX–hydroxyapatite–polycaprolactone nanoparticles (DX/HAp/PCL) to modify DX osteogenic potential.
Methods: Employing a 23-factorial design, we first optimized HApN for surface-area attributes to maximize DX loading. Composite DX/HAp/PCL were then realized using a simple emulsification technique, characterized using various in vitro methods, and evaluated for in vitro osteogenesis.
Results: The developed HApN exhibited a favorable crystalline structure, Ca:P elemental ratio (1.67), mesoporous nature, and large surface area. DX/HAp/PCL achieved the highest reported entrapment efficiency (94.77%± 1.23%) of DX in PCL-based particles. The developed composite system achieved controlled release of the water-soluble DX over 24 days. Moreover, the novel composite nanosystem managed to significantly ameliorate DX cytotoxicity on bone-marrow stem cells, as well as enhance its overall proliferation potential. Alkaline phosphatase and mineralization assays revealed superior osteodifferentiation potential of the composite system. Quantification of gene expression demonstrated that while DX solution was able to drive bone-marrow stem cells down the osteogenic lineage into immature osteoblasts after 10-day culture, the innovative composite system allowed maturation of osteodifferentiated cells. To the best of our knowledge, this is the first work to elaborate the impact of DX on the expression of osteogenic genes: RUNX2, OSP, and BSP. Further, the osteogenicity of a DX-loaded particulate-delivery system has not been previously investigated.
Conclusion: Our findings indicate that repurposing low-dose DX in complementary biomaterial-based nanosystems can offer a prominent osteogenic candidate for bone-regeneration purposes.

Keywords: bone regeneration, bioactivity, mesenchymal stem cells, drug repositioning, osteodifferentiation

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