MEDICAL DEVICES BASED ON BIOINSPIRED CERAMICS - Advanced Biomaterials: Fundamentals, Processing, and Applications - page 352

11.4 Bioinspired Ceramics Coated with Bioactive Materials 384

11.4.1 Hydroxyapatite and Substituted Apatites 385

11.4.2 Bioactive Glasses 386

11.4.3 Coating Deposition Techniques 387

11.4.4 Physico - Chemical Properties of the Hydroxyapatite and
Substituted Apatite Coatings

389

11.4.5 Physico - Chemical Properties of the Bioactive
Glass Coatings 392

11.5 Biocompatibility Studies for Medical Applications 396

11.5.1 In Vitro Cytotoxicity Test 396

11.5.2 In Vitro Cell Attachment and Proliferation Tests 398

11.5.3 In Vivo Biocompatibility Studies 400

11.6 Conclusions 401

Acknowledgments 403

References 403

11.1 OVERVIEW

Today biomedical devices are essential for improving human health and quality
of life. Now that biomaterials have been optimized with the aim to minimise
rejection by the host organism, they have entered a new stage in which they can
be designed with bioactive properties, exchanging stimuli with the surrounding
tissue and inducing specifi c cellular reactions. Man-made material solutions
should now take inspiration from the most complex naturally organised chemical
and biological structures, taking advantage of the knowledge that nature has been
optimizing for over millions of years.
This chapter introduces the development of innovative bioinspired materials,
based on silicon carbide ceramics coated with bioactive materials, as new bio-
medical devices. The bioinspired silicon carbide is fabricated via the pyrolysis and
infi ltration of natural wood-derived preforms; further, the technological process
is completed with the deposition of a bioactive coating by laser techniques. The
result is a new generation of light and high-strength ceramic products that mimic
the natural structure of the bone tissues, incorporating the unique property of
interconnected porosity, which allows the internal growth of tissue and favours
angiogenesis. To further improve the fi xation and osteointegration performance,
the bioinspired ceramics are coated with a bioactive layer of hydroxyapatite, sub-
stituted apatites or silica-based glasses. Both material properties and deposition
methods are reported.
In vitro biocompatibility studies demonstrate that the biological response
of this ceramic product is similar to titanium controls, and in vivo implan-
tation experiments show how it gets colonized by the hosting bone tissue
due to its unique interconnected hierarchic porosity. The excellent biocompat-
ibility of these innovative bioinspired materials reported here enters a new
stage of very promising light, porous, and metal-free devices for medical
applications.