Analysis of Polylactic Acid, Bioglass and Hydroxyapatite coating as biomaterials for the development of prostheses

Written by | Ciencias, Especial Biomateriales

One of the main health issues in Mexico is the lack of available prostheses due to the cost of the devices and the procedure to make the implantation. This problem has encouraged researchers to review traditional biomaterials and to look for more affordable alternatives.   

To begin, the biomaterial concept must be defined. According to the National Institute of Biomedical Imaging and Bioengineering (2020), biomaterials are “any matter, surface, or construct interacting with biological systems”. According to Narayanan et al. (2016) Polylactic Acid (PLA) is a light and durable polymer biomaterial which has different applications. Also, PLA can be used to fabricate sutures, drug delivery systems, and tissue engineering. It is important to mention that PLA is cheaper compared to other biomaterials and can also be used to make 3D printed scaffolds. 

On one hand, Bioglass (BG) is a biocompatible silica-based glass with osteoconductive properties that releases calcium ions which promote bone growth. In other words, the material imitates bone tissue and stimulates its regrowth (Krishnan & Lakshmi, 2013). On the other hand, Hydroxyapatite (HA) is one of the most studied biomaterials in the medical field regeneration (Pepla et al., 2014) due to its proven properties like biocompatibility and for being the principal component of the minerals found in teeth and bones. HA can chemically bond to bones preventing toxicity or inflammation, helping during bone regeneration. 

However, there are several factors that must be considered for a biomaterial to be considered as a viable option in the development of medical devices, such as a prosthesis. The international standard that regulates the biocompatibility of materials is ISO 10993. This standard describes the general principles governing the biological evaluation of medical devices through a risk management process, the general categorization of medical devices according to the nature and duration of contact with the body, and the evaluation of the biological safety of the medical device. 

Different tests have been performed with the biomaterials presented above. For example, the strength and toxicity of HA were evaluated by an analysis performed by Fernandez et al.,(2006), making an implantation on the femur and jaw of Beagle dogs. The procedure consisted in filling fractures on the bones and analyzing the effect the HA had on the site of the fracture. It was concluded that the HA had no negative effect on the recovery of the fracture, since the implantation caused no immune response, facilitating the bone tissue proliferation. 

Oppositely, BG has had  more recent discoveries. In the study realized by Tabia et al. (2021), a 3Dprinted porous scaffold based on a stainless-steel alloy with a coating of Bioglass was implanted in vitro. Due to the processthe BG becomes a gel and is applied to the stainless-steel scaffold. In consequence, the authors realized that this hybrid structure exhibited a reduced stiffness and weight compared to traditional biomaterials. Also, thanks to the BG layer applied to the scaffold, the bone density near the site of implantation increased, implying that the coating improves the in vitro bioactivity in a simulated body fluid medium.  At last, it was described that this hybrid biomaterial can carry other substances such as growth factors, antibiotics, and anti-inflammatory drugs to improve the biological properties of this new biomaterial. 

In addition, though the stainless-steel scaffold presented by Tabia et al. (2021), is rigid enough to resist the forces which will be applied to it, is not the optimum option due to the residue this biomaterial leaves behind when biodegrading. This is the reason why these biomaterials (HA and BG) must be combined with another harder biomaterial to obtain an optimal candidate for the construction of prostheses. 

Until this point the beneficial properties of BG and HA have been proven. Nevertheless, these biomaterials being derived from ceramics are not strong enough to deliver their purpose as prostheses as they present a fracture risk due to the forces they must resist when attached to a limb. 

Alksne et al. (2020), realized a study where a compound with HA and BG was applied on a polylactic acid (PLA) scaffold. As mentioned before, PLA is a resistant and cheaper biomaterial in comparison to stainless steel. Through a series of experiments in vivo, meaning in living organisms, and in vitro, the authors demonstrated that the mixture of HA and BG have better bone regenerative properties as a result of the bone tissue adhering to the surface of the PLA scaffold within 24 hours after the implantation. Nevertheless, the mixture of PLA+BG scaffold had better results than the PLA+HA when they were treated as individual samples (Figure 1).  

Figure 1. Composites of HA and BG with PLA through a scanning electron microscope (Alksne et al., 2020)

To conclude, biomaterials represent a viable solution for the lack of available prostheses. New technologiessuch as 3D printing and the creation of compounds, which take the best properties of each biomaterial, have created new approaches for these problems. Given the analysis done, it was observed that due to its capabilities of weight resistance and the biocompatibility the PLA+BG composite represents a better solution. More studies need to be conducted for this biomaterial to be applied on human cases. Nonetheless, this opens opportunities for more research to be done on the matter and generate more solutions. 


Alksne, M., Kalvaityte, M., Simoliunas, E., Rinkunaite, I., Gendviliene, I., Locs, J., … & Bukelskiene, V. (2020). In vitro comparison of 3D printed polylactic acid/hydroxyapatite and polylactic acid/bioglass composite scaffolds: Insights into materials for bone regeneration. Journal of the mechanical behavior of biomedical materials104, 103641. 

Fernández, R. D., Vélez, J. U., Sosa, V. R., Carrodeguas, R. G., Pelayo, Z. C., Rodríguez, E. I., & Hernández, M. R. (2006). Evaluación anatomopatológica experimental de la implantación en hueso de la Hidroxiapatita Sintética (Apafill-G). Revista Habanera de Ciencias Médicas5(4), 1-8. 

ISO 10993-1:2010. Biological evaluation of medical devices – Part 1: Evaluation and testing within a risk management process (ISO 10993-1:2009). Retrieved on March 26th, 2021 from:  

Krishnan, V., & Lakshmi, T. (2013). Bioglass: A novel biocompatible innovation. Journal of advanced pharmaceutical technology & research, 4(2), 78–83. 

Narayanan, G., Vernekar, V . N., Kuyinu, E. L., & Laurencin, C. T. (2016). Poly (lactic acid)-based biomaterials for orthopaedic regenerative engineering. Advanced drug delivery reviews, 107, 247–276. 

National Institute of Biomedical Imaging and Bioengineering, (2020). Glossary of Terms. Retrieved on March 26th, 2021 from: 

Pepla, E., Besharat, L. K., Palaia, G., Tenore, G., & Migliau, G. (2014). Nano-hydroxyapatite and its applications in preventive, restorative and regenerative dentistry: a review of literature. Annali di stomatologia, 5(3), 108–114.  

Tabia, Z., Bricha, M., El Mabrouk, K., & Vaudreuil, S. (2021). Manufacturing of a metallic 3D framework coated with a bioglass matrix for implant applications. Journal of Materials Science56(2), 1658-1672. 

About the authors

Carolina Macías Martínez
Graduated in Mechatronics Engineering and 8th semester student in Biomedical Engineering. Participated in an automation project at ABD Systems. Subsequently, performed an internship at the Universitat de Valencia, Spain. In addition, she has contributed as a leader of the Robotics and Biomedical Engineering workshops in the Pi-ensa Program: Engineering and Science for children and young people. Currently she is collaborating in a company dedicated to the maintenance of medical equipment in Puebla.

Ilse Guadalupe Becerra Luna
8th semester student in Biomedical Engineering.

Horacio Guzmán Fernández.
9th semester student in Biomedical Engineering. Participated in the “Printing of fast prosthesis prototypes and biomedical equipment” project. Also collaborating with NUBIX organization which focuses on the storage of medical images (PACS) in the cloud as Chief of Support.


Last modified: 13 mayo, 2021

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