A new biomaterial that contains chicken eggshell membrane and has been developed by researchers from the Andalusian Institute of Earth Sciences (IACT), the joint research center of the Higher Council for Scientific Research (CSIC) and the University of Granada, Together with the universities of Oviedo, Jaén, National of Colombia and together with the Andalusian Health Service, it promotes the formation of new bone cells, so it could be useful as bone regeneration material.
The product is based on a membrane with a mineralized external face, which induces the formation of new bone cells, and an unmineralized internal face, which acts as a barrier against unwanted cell invasion from the surrounding gingival tissue towards the area of bone formation. bone. These results have been published in the journal Biomaterials Advances and both the resulting material and its applications have been protected by patent in Spain, at the same time that the process for its protection at an international level has begun.
The egg membrane is a unique biopolymeric material formed by collagen fibers (type I, V and X) and covered with white proteins, shell matrix proteins and carbohydrates such as glycosaminoglycans and hyaluronic acid. On its external side, the membrane has structures called nipples composed of proteoglycans, molecules that act as nucleation centers (change of state through which solid bodies are formed from a previous liquid phase) of calcium carbonate, the mineral component of the shell.
“In the case of pulp capping, the membrane biomaterial covers an accidental exposure of the dental pulp, with the aim of preserving the vitality of the tooth”
The composition and function of the external and internal faces of the membrane are different. While the external face promotes the nucleation of calcium carbonate – and, therefore, the formation of the shell –, the internal face, which is in contact with the yolk and the white, inhibits the formation of the mineral. Birds take advantage of this double function of the membrane to form the resistant eggshell material: a shell of calcium carbonate that protects the embryo from external aggressions and, at the same time, allows it to hatch easily from within. This duality has proven to be a promising characteristic that in this work has served to develop a biohybrid material with future applications in guided bone regeneration and pulp capping.
A bone regeneration technique that is already used in dentistry
This technique is already widely used in dentistry to promote the regeneration of mandibular bone, for example, in the jaws, before placing an implant, and the repair of bone defects. To do this, small membranes made of natural resorbable polymers (collagen, chitosan and gelatin, among others) or synthetic ones (polylactic acid (PLA), polyglycolic acid (PGL) and their copolymers) and a bone graft or regenerating material such as a phosphate are used. calcium.
The role of these membranes is to act as a physical barrier between the bone tissue and the surrounding gingival tissue, so as to prevent the invasion of cells from the gingival tissue to the bone graft area and, in addition, serve as support for bone formation. new. At the same time, they are required to be resorbable to avoid a second surgery.
The biomaterial developed in this work consists of a chicken egg shell membrane, covered on its external side by calcium phosphate nanocrystals (apatite phase), preserving its internal side without mineralization. Calcium phosphates are a group of minerals that contain calcium and phosphate ions in their composition, and crystallize in different phases, including the apatite phase, which is the main mineral component of our bones and teeth.
“For this we have used an innovative crystallization technique called ‘crystallization by vapor diffusion’, which pursues the precipitation of apatite nanocrystals with characteristics similar to the apatite of the bone that is intended to be regenerated. The biomaterial obtained is therefore bifunctional, osteoinductive on the external side and barrier against cellular invasion on the internal side, and can replace the current materials used in guided bone regeneration, that is, the sum of a membrane plus a bone graft. The membrane on its external side is, therefore, similar to mineralized tissues and on its internal side, similar to soft tissues. The membrane is also resorbable,” explains Jaime Gómez Morales, from the IACT Crystallographic Studies Laboratory and principal investigator of the study.
In vitro tests have confirmed that apatite-coated egg membrane material has improved mechanical properties relative to the membrane itself, biocompatibility and the ability to stimulate the growth and development of bone-forming cells, including the osteogenic differentiation of mesenchymal stem cells ( important for making and repairing bone tissue). These properties are key to determining the potential for clinical application of the material obtained in this study and are guarantors to advance in its research. In this way, the material can also be used for the regeneration of injuries to other bones in the body.
“In the case of pulp capping, the membrane biomaterial covers an accidental exposure of the dental pulp, with the aim of preserving the vitality of the tooth. Currently, the materials used for pulp capping are composed of calcium hydroxide, calcium silicates and composite resins, presenting limitations in their clinical application due to their compositional incompatibility with dental tissues. Our material, on the other hand, contains calcium phosphates (apatite) which are the same components present in dental tissues, such as dentin or enamel. This makes it a promising and compatible option for pulp regeneration,” explains Gómez Morales. “Thanks to these positive results, we are committed to optimizing its properties, so that it can contribute substantially to medical fields such as Traumatology and Regenerative Dentistry,” he adds.
Source: Higher Council for Scientific Research (CSIC)
