{"id":9068,"date":"2020-11-30T18:45:12","date_gmt":"2020-11-30T21:45:12","guid":{"rendered":"https:\/\/www.sbpmat.org.br\/?p=9068"},"modified":"2020-12-21T16:44:00","modified_gmt":"2020-12-21T19:44:00","slug":"artigo-em-destaque-estrategia-biomimetica-para-sintese-de-nanotubos-que-estimulam-a-regeneracao-ossea","status":"publish","type":"post","link":"https:\/\/www.sbpmat.org.br\/en\/artigo-em-destaque-estrategia-biomimetica-para-sintese-de-nanotubos-que-estimulam-a-regeneracao-ossea\/","title":{"rendered":"Biomimetic strategy for the synthesis of nanotubes that stimulate bone regeneration."},"content":{"rendered":"

Experts say that, to date, there is nothing better than a natural bone to help regenerate another natural bone. In fact, despite the enormous advances in the area of biomaterials, there is still no synthetic material that works as well as autogenous bone graft (bone extracted from the patient himself) to encourage bone tissue regeneration – a process that occurs in our body regularly and spontaneously, but it is necessary to stimulate this through graft implantation when we experience noticeable bone loss due to trauma or disease. In this process, the basic unit of bone formation is the mineralized collagen fibril, a collagen cylinder formed by a group of cells called osteoblasts, which is filled and coated with calcium phosphates during the \u201cbiomineralization\u201d process.<\/p>\n

A study carried out by researchers from Brazil with collaborators from France took an important step in this context. Using a strategy inspired by nature, the scientific team produced, in the laboratory, a material that is very similar to mineralized collagen fibrils, in shape, size and structure. Collagen structures, which are expensive and difficult to handle proteins, were not used in this research. Instead, the researchers produced tubes (about 200 nm in diameter) which are very similar to fibrils, but composed of calcium phosphate crystals, the main inorganic component of bones, and strontium, an element used to treat osteoporosis, which helps reduce bone tissue loss and increase bone formation.<\/p>\n

In in vitro<\/em> tests, the material showed that it is not toxic to cells and that it generates the necessary conditions for bone tissue formation. In addition, it showed the ability to release strontium ions for long periods in controlled doses – an essential parameter for the long-term development of safe therapies, since in excess it can lead to the weakening of bones.<\/p>\n

Strategy<\/strong><\/p>\n

\"Procedure
Procedure adopted to produce the bone regeneration material. The use of a membrane (center) allowed to obtain the desired characteristics.<\/figcaption><\/figure>\n

To produce the material\u00a0having a cylindrical structure of controlled dimensions, the team employed a strategy that is used by several living organisms to generate teeth, shells and bones: physical confinement, which is nothing more than the use of a mold to induce a material to follow a specific morphology and size.<\/p>\n

The mold used was a polycarbonate membrane, commercially available, which has cylindrical pores of 200 nm in diameter, similar in size to bone collagen fibrils. The membrane was submerged for twelve hours in a solution containing phosphate, calcium and strontium, which penetrated the pores. After drying the membrane in the presence of compounds that triggered mineralization, the polycarbonate was dissolved, allowing to separate and analyze the material that had formed inside the pores.<\/p>\n

\u201cBy delimiting the physical environment in which the nucleation and growth processes of the mineral occur, we obtained nanotubes with highly controlled morphology, composition and size,\u201d says Ana Paula Ramos, professor at the\u00a0University of S\u00e3o Paulo (USP), campus Ribeir\u00e3o Preto, and corresponding author of a recently published article reporting the study.<\/p>\n

The same procedure, but without the use of molds, resulted in agglomerated spherical nanoparticles with very different characteristics from the collagen fibrils that were sought to emulate.<\/p>\n

Surprise<\/strong><\/p>\n

The research was carried out within the PhD in Chemistry of Camila Bussola Tovani, which was carried out with funding from FAPESP, supervised by Professor Ana Paula Ramos, and defended this year at USP, campus Ribeir\u00e3o Preto.<\/p>\n

The initial idea of the project was to understand how strontium ions, used in the treatment of osteoporosis, acted on the bone mineralization mechanism. As this process, in the body, occurs in a situation of confinement, limited by the framework formed by the collagen fibrils, Camila and her advisor decided to use a mold to study how the calcium phosphate mineralization occurs in the presence of strontium ions.<\/p>\n

\u201cDuring the structural characterization, we found high similarity between the particles obtained and the mineralized collagen fibrils that form the bones, which encouraged us to conduct biological investigations\u201d, says the professor. \u201cWhat really surprised us, was the possibility of controlling particle properties such as mineral phase, morphology and size, by simply changing the medium in which precipitation occurred,\u201d adds Ana Paula, who suggests that the same strategy can be applied to synthesize other inorganic particles for different applications in which the control of physicochemical properties is essential.<\/p>\n

The nanotubes were produced and characterized in the Physical and Chemical Laboratory of Surfaces and Colloids, coordinated by Professor Ana Paula. Biological tests were carried out in other laboratories at USP campus in Ribeir\u00e3o Preto, through collaborations with Professor Pietro Ciancaglini and Professor Sandra Fukada.<\/p>\n

The study also benefited from two collaborations by Professor Ana Paula with researchers from France. The first, with the researcher Alexandre Gloter (Universit\u00e9 Paris-Saclay), made it possible to investigate the formation mechanism and to characterize the nanotubes by advanced spectroscopy and microscopy techniques. The second, with researcher Nadine Nassif (Sorbonne Universit\u00e9), helped to understand the bone mineralization processes. \u201cIt is interesting that the initial contact with Dr. Alexandre Gloter took place in Brazil during TEM Summer School, organized at CNPEM by LNNano, and that the BEPE-FAPESP scholarship allowed Camila Tovani to\u00a0stay at the Chimie de la Matiere Condens\u00e9e<\/em>\u00a0laboratory at Sorbonne Universit\u00e9, under the supervision of Dr. Nadine Nassif for one year,\u201d says Ana Paula Ramos. \u201cThe investment of Brazilian funding agencies in internationalization, both in bringing and sending researchers abroad, had an important impact on this research,\u201d she concludes.<\/p>\n

From the laboratory to the market<\/strong><\/p>\n

According to Professor Ana Paula, after conducting an investigation to validate the performance of nanotubes in animal models, the material will be able to be used to locally fill small bone defects. The nanotubes could also be incorporated into polymeric matrices that are used in orthopedic and cranio-maxillofacial surgery to replace, fill or repair bone defects caused by infections, injuries and neoplasms. In addition, the material could be incorporated into toothpaste formulations for the treatment of tooth hypersensitivity, since some toothpastes used for this purpose have strontium in their composition.<\/p>\n

\u201cThe biggest challenge to make the particles as product is to find companies in the industry interested in the technology, which would allow us to develop formulations in the short term,\u201d says the researcher.<\/p>\n

\"The
The authors of the paper. From the left: Camila Bussola Tovani, Tamires Maira Oliveira, Mariana P. R. Soares, Nadine Nassif, Sandra Y. Fukada, Pietro Ciangaglini, Alexandre Gloter and Ana Paula Ramos.<\/figcaption><\/figure>\n

[Paper:\u00a0Strontium Calcium Phosphate Nanotubes as Bioinspired Building Blocks for Bone Regeneration<\/strong><\/em>. Camila B. Tovani, Tamires M. Oliveira, Mariana P. R. Soares, Nadine Nassif, Sandra Y. Fukada, Pietro Ciancaglini, Alexandre Gloter, and Ana P. Ramos.\u00a0ACS Appl. Mater. Interfaces 2020, 12, 39, 43422\u201343434. doi.org\/10.1021\/acsami.0c12434.]<\/p>","protected":false},"excerpt":{"rendered":"

Experts say that, to date, there is nothing better than a natural bone to help regenerate another natural bone. In fact, despite the enormous advances in the area of biomaterials, there is still no synthetic material that works as well as autogenous bone graft (bone extracted from the patient himself) to encourage bone tissue regeneration […]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"_links":{"self":[{"href":"https:\/\/www.sbpmat.org.br\/en\/wp-json\/wp\/v2\/posts\/9068"}],"collection":[{"href":"https:\/\/www.sbpmat.org.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.sbpmat.org.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.sbpmat.org.br\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sbpmat.org.br\/en\/wp-json\/wp\/v2\/comments?post=9068"}],"version-history":[{"count":3,"href":"https:\/\/www.sbpmat.org.br\/en\/wp-json\/wp\/v2\/posts\/9068\/revisions"}],"predecessor-version":[{"id":9110,"href":"https:\/\/www.sbpmat.org.br\/en\/wp-json\/wp\/v2\/posts\/9068\/revisions\/9110"}],"wp:attachment":[{"href":"https:\/\/www.sbpmat.org.br\/en\/wp-json\/wp\/v2\/media?parent=9068"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.sbpmat.org.br\/en\/wp-json\/wp\/v2\/categories?post=9068"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.sbpmat.org.br\/en\/wp-json\/wp\/v2\/tags?post=9068"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}