Nanocrystallic hydroxyapatite from biological material for practical health care

SUMMARY

Human and animal bone tissue is composed of the protein and mineral components such as calcium hydroxyapatite. Chemically synthesized hydroxyapatite, a highly dense crystalline material is used to fill bone defects during surgical treatment in traumatology and orthopedics, dentistry, and maxillofacial surgery. Nano crystalline form of hydroxyapatite calcium has another organizational structure with other methods of hydroxyapatite synthesis, a method of applying various implants to the surface, biocompatibility, toxicological and allergenic manifestations, mainly used for coating implants, dental cements and medical pastes due to its high bioactivity and the possibility of creating composite materials on its basis [1]. This paper describes the process of synthesis of hydroxyapatite with the method of calcination using the egg shell of birds as a biological raw material. Electron microscopy studies showed that the resulting powder is a single-phase, thermally stable up to 900 ° C and morphologically homogeneous. The globules are composed of nano crystals with average size of around 50 nm.

According to the World Health Organization, the development of the technogenic sphere severely damages the human health. In particular, the bone tissue is one of the most vulnerable structures of the body. It is well known that human and animal bone tissue consists of a protein matrix, individual for every biological individual, and a mineral component composed of an inorganic calcium and phosphorus compound, calcium hydroxyapatite The use of chemically synthesized hydroxyapatite to fill bone defects during surgical treatment started in the late 70s of the XX century and is widely used at the present. This material is widely used in the modern traumatology, orthopedics, dentistry and maxillofacial surgery. Calcium hydroxyapatite, currently used to fill bone tissue defects, is basically a dense, highly crystalline material that withstands signifi - cant mechanical stresses by introducing hardening additives. Upon creating implants based on hydroxyapatite, researchers studied deeply methods of hydroxyapatite synthesis and its application to different surfaces of various implants, biocompatibility, toxicological and allergenic manifestations, but its structural organization was poorly investigated. For coating implants, dental cements and medical pastes, the nano crystalline form of hydroxyapatite is used due to its high bioactivity and the possibility of creating composite materials on its base. [1]

Experimental part HAP was synthesized by calcination using a biological source - the egg shell of birds. Electron microscopy studies showed that the resulting powder is a single-phase, thermally stable (up to 900 ° C), morphologically homogeneous and is composed of 4-5 μm globules, which in turn are consist of nanocrystals of the size of around 50 nm.

A distinctive feature of our technique is obtaining of one of the basic components of the reaction - calcium oxide (CaO) during the processing of the eggshell. The egg shell is used as a main material because it is composed of calcite - CaCO3 for 95%. The remaining is an organic matter - several layers of interlacing protein fibers and various mineral salts (<1%), placed similar to calcite, on the surface of these protein fibers. On heating, CaCO3 decomposes into CaO and CO2:

CaCO₃ → CaO + CO₂ (T = 900 °C) (1)

Prepared shell, containing CaCO3, was washed and calcined at 900 ° C. After 30 minutes, the color of the egg shell turned into black, and upon further 3 hours it became white. The color change showed that most of the organic materials were burned. The powders were crushed in an agate mortar followed by an exothermic reaction with phosphoric acid. Further details of the mixing procedure and powder preparation are presented in Table 1.

Table 1. Calcination of the eggshell

The principle of electrospinning device is simple: a polymer solution is mechanically squeezed out of a syringe. From the tip of this syringe needle, on which additional high voltage is applied, a stream of the solution emerges. Then, as the stream progresses, the solvent is evaporated, and the remaining material, which is a forming fiber, is collected at the second high voltage electrode.

Figure 4 shows the 3D synthesis of porous fibrous frameworks. Nano-HA (nano-hydroxyapatite) powder was synthesized from the raw materials. The resulting n-HA powder was added to acetic acid, forming 9.38% w / v solution. This solution was then mixed with cellulose acetate (AC) solution and this mixture was further dissolved in acetone to form a 15% w / v composition. The mixed solution (71-29% acetone / acetic acid) was introduced into a standard vertical electrospinning unit and electrospun was conducted under the following conditions: flow rate 9.6 ml / h, voltage 19 kV and distance 10 cm from the needle to the manifold [3,7-8].

Conclusion

Thus, based on the results obtained, the following conclusions can be drawn:

1. Hydroxyapatite was experimentally synthesized from the egg shell of birds.
2. Phase composition of the obtained hydroxyapatite was studied.
3. Using electrospinning method on hydroxyapatite base will allow obtaining a material for effective replacement and regeneration of the bone tissue.

REFERENCES

1. Белякова Е.Г. Технология гидроксиапатита кальция - стимулятора// Екатеринбург. 2002. - № 5. - С. 183.
2. Д. Л. Голощапов, В. М. Кашкаров, Н. А. румянцева, П. В. Середин, А. С. Леньшин, Б. Л. Агапов, Э. П. Домашевская// Конденсированные среды и межфазные границы, Том 13, № 4, С. 427—441
3. Csaba Balarzsia, Ferenc Werbera, Zsuzsanna KoЁverra, Eniko Horvarthb, Csaba Nermeth // Preparation of calcium-phosphate bioceramics from natural resources. Journal of the European Ceramic Society 27 (2007) 1601-1606
4. P. Gouma, R. Xue, C.P. Goldbeck, P.Perrotta, C. Balazsi // Nano-hydroxyapatite – Cellulose acetate composites for growing of bone cells. Journal of the European Ceramic Society
5. Ramesh S., Tanb C. Y., Hamdib M., et al. // International Conference on Smart Materials and Nanotechnology in Engineering. 2007. V. 6423. 64233A. P. 1—6.
6. Шпак А.П., Карбовский В.Л., Трачевский В.В. Апатиты. Академ.периодика, 2002. C. 414.
7. Murugan R., Ramakrishna S. // American Journal of Biochemistry and Biotechnology. 2007. V. 3. № 3. С. 118—124.
8. Rey C., Combes C., Drouet C., et al. // Material science and engineering. 2006. P. 1—8.
9. Елемесова Ж.К., Бодыков Д.У., Дабынов Б.М., Темирбаев М.А., Алиев Е.Т., Мансуров З.А. Получение нано кристаллического гидроксиапатита из природных ресурсов для регенерации костной ткани. VIII международный симпозиум «Физика и химия углеродных материалов/нано инженерия», C.171-172, Сентябрь 17-19, 2015, Алматы.