Tissue Regeneration Using 3D-Printed Bioactive Glass Scaffolds

The medical industry is already using 3D printing, also referred to as additive manufacturing (AM) in many different areas. For instance, 3D printing of hearing aids has become a routine process, and many studies have also been reported where 3D printers were used for developing patient-specific implants made from metal or plastic.^1-4

Today, researchers are integrating sophisticated methods like 3D printing techniques and materials such as bioactive glasses to develop customized implants and scaffolds that easily dissolve in the body and are then substituted with new tissues.

An example of scaffold in cell culture. Image credit: nutthapong moonkum | Shutterstock

What is bioactive glass?

Bioactive glasses are phosphosilicate materials that contain calcium and sodium. Within the body, they strongly adhere to tissues and offer surfaces for growth of new cells and tissues. These materials ultimately dissolve, releasing calcium into the blood. This then reacts to form a rigid and hard mineral called hydroxylapatite, an important part of bone. In this manner, bioactive glasses can assist in bone regeneration.

One can also customize the composition of bioactive glasses to give them antimicrobial, therapeutic, and cell recruiting effects. Bioactive glasses can even be integrated with other materials to develop composites with many different properties, leading to a host of medical applications.^8,9 Bone grafting is a complicated regenerative procedure, but since bioactive glasses are synthetic materials they are well-suited for such procedures.

Steve Jung, CTO at Mo-Sci, a top supplier of bioactive glass, highlighted the many beneficial properties of bioactive glass and added that “Since its inorganic, it’s essentially a limitless supply; you can always make more, whereas bone or other types of materials used in medical applications you need cadaver or patient supplied bone, and sometimes there’s not enough.”

Also, bioactive glass grafts are man-made materials and hence they are not very costly and do not have potential for disease transmission.⁸

3D printing bioactive glass

In clinical practice, putties and particles of bioactive glass are widely used to aid the regeneration of bone, and this has been used in over a million patients.^9,11 Scaffolds can also be made from bioactive glasses to support the regeneration of tissues in larger areas. Foaming methods can be used to produce bioactive glass scaffolds, leading to scaffolds with pore architectures that emulate the bone structure.

Conversely, controlling the pore structures of such scaffolds would be rather difficult and the scaffolds obtained would also be relatively fragile. Scaffolds are often used by surgeons for bone grafts and they can be load bearing and have precise pore architectures. With the help of 3D printing, bioactive glass structures with increased mechanical strength and finely controlled pore structures can be produced.^9,12

3D printing is a special process in which several layers of a material are laid down to create 3D structures from a digital model. Generally, 3D printing employs metals or polymers to create structures, but today scientists are using this process to 3D print composites and bioactive glass materials. This allows bioactive glass scaffolds to be accurately developed in terms of their pore structure and the ultimate shape of the scaffold.^13-15

3D-printed architectures made from bioactive glass can be employed for innovative solutions in tissue scaffolding, medical implants, surgery, and dental implants. 3D printing allows a patient to be scanned following which a special scaffold or implant can be developed and printed with the exact properties and size for them.^9,16

While the use of 3D-printed bioactive glasses is yet to become widespread, there have been many studies regarding their use in human patients as well as animal models that require special and customized solutions. Research is ongoing on the potential of 3D-printed composites and bioactive glasses, and the procedure of 3D printing bioactive glass structures is still under optimization, especially with respect to improving the mechanical strength and porosity of the ensuing scaffolds, and choosing the most suitable binder materials and post processing methods.^16-18 Research is also ongoing to incorporate drugs, growth factors, and live cells into bioactive glass scaffolds with the help of 3D printing.^16,19

Mo-Sci’s bioactive glass

While 3D-printed bioactive glass scaffolds can result in customized and precisely designed scaffolds for bone grafting, the process of printing bioactive glasses is still being optimized.

A wide range of bioactive glasses are offered by Mo-Sci for medical and research applications, and custom compositions are also available on special request.²¹

References

1. https://www.bbc.co.uk/news Accessed May 11th, 2017.
2. http://www.bbc.co.uk/news/technology-16907104 Accessed May 11th, 2017.
3. http://www.nature.com/news/3-d-printed-windpipe-gives-infant-breath-of-life-1.13085 Accessed May 11th, 2017.
4. https://www.forbes.com/sites/rakeshsharma/2013/07/08/the-3d-printing-revolution-you-have-not-heard-about/#19e1ce321a6b Accessed May 11th, 2017.
5. “3D printing & medical applications” Carsten Engel at TEDxLiege, 2014. Available from: https://www.youtube.com/watch?v=y87RmyBxKic Accessed May 11th, 2017.
6. Gross BC, Erkal JL, Lockwood SY, Chen C, Spence DM, “Evaluation of 3D Printing and Its Potential Impact on Biotechnology and the Chemical Sciences” Analytical Chemistry 86(70):3240-2253, 2014.
7. Trombetta R, Inzana JA, Schwartz EM, Kates SL, Awad HA, “3D Printing of Calcium Phosphate Ceramics for Bone Tissue Engineering and Drug Delivery” Anals of Biomedical Engineering 45(1):23-44, 2017.
8. “The benefits of bioactive glass” MoSci, 2016. Available from: https://vimeo.com/157284843 Accessed May 11th, 2017.
9. “Julian Jones' Inaugural Lecture at Imperial College London 2016” Julian Jones, 2016. Available from: https://www.youtube.com/watch?v=Kr0FKozsj88 Accessed May 11th, 2017.
10. Montazerian M, Zantto ED, “History and trends of bioactive glass-ceramics” Journal of Biomedical Materials Research Part A 104A:1231-1249, 2016
11. Van Gestel NAP, Geurts J, Hulsen DJW., van Rietbergen B, Hofmann S, Arts JJ, “Clinical Applications of S53P4 Bioactive Glass in Bone Healing and Osteomyelitic Treatment: A Literature Review” BioMed Research International 2015:684826, 2015.
12. Hench LL, Jones JR, “Bioactive Glasses: Frontiers and Challenges” Frontiers in Bioengineering and Biotechnology 3:194, 2015.
13. Qi X, Pei P, Zhu M, Du X, Xin C, Zhao S, Li X, Zhu Y, “Three dimensional printing of calcium sulfate and mesoporous bioactive glass scaffolds for improving bone regeneration in vitro and in vivo” Scientific Reports 7:42556, 2017.
14. Wu C, Luo Y, Cuniberti G, Xiao Y, Gelinsky M, “Three-dimensional printing of hierarchical and tough mesoporous bioactive glass scaffolds with a controllable pore architecture, excellent mechanical strength and mineralization ability.” Acta Biomaterialia 7(6):2644-2650, 2011.
15. Profeta AC, Huppa C, “Bioactive-glass in Oral and Maxillofacial Surgery” Craniomaxillofacial Trauma & Reconstruction 9(1):1-14, 2016.
16. Bose S, Vahabzadeh S, Bandyopadhyay A, “Bone tissue engineering using 3D printing” Materials Today 16(12):496-504, 2013.
17. Murphy C, Kolan KCR, Long M, Li W, Leu MC, Semon JA, Day DE, “3D printing of a polymer bioactive glass composite for bone repair” Solid Freedom Fabrication 2016: Proceedings of the 27th Annual International Solid Freedom Fabrication Symposium, 2016.
18. Bergmann C, Lindner M, Zhang W, Koczur K, Kirsten A, Telle R, Fischer H, “3D printing of bone substitute implants using calcium phosphate and bioactive glasses” Journal of the European Ceramic Society 30(12):2563-2567, 2010.
19. Murphy C, Kolan K, Li W, Semon J, Day D, Leu MC “3D bioprinting of stem cells and polymer/bioactive glass composite scaffolds for bone tissue engineering” International Journal of Bioprinting 3(1):1-11, 2017.
20. Petola M, Vallittu PK, Vuorinen V, Aho AAJ, Aitasalo KM, “Novel composite implant in craniofacial bone reconstruction” European Archives of Otorhinolaryngology 269(2):623-628, 2011.
21. http://www.mo-sci.com/bioactive-glass/ Accessed May 11th, 2017.

About Mo-Sci

Mo-Sci, a world leader in precision glass technology, explores and develops new and exciting ways for their products and services to integrate within a wide variety of useful applications.

Mo-Sci has become a world leader in the research, development and manufacturing of glasses for specialty applications.

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