Synthesis and characterization of hybrid biopolymer membranes containing apatites and silver nanoparticles

Abstract

The treatment of fractures and defects in bone matrix represents a major challenge for orthopedic surgeons, as mainly the risk of rejection and infection. In this context, tissue engineering and regenerative medicine have sought new approaches to solve, or soften, this problem, through the development of designed biomaterials for implants which present potential osteogenic. In this perspective, it highlights the study of hybrid materials, as found in the bone tissue. Combinations of organic and inorganic phases have been investigated for the development of biomaterials which support for tissue engineering bone seeking to materials that mimic the composition and structural organization of the bone, and also exhibit improved physic-chemistry properties desirable for use in implants. In this perspective, materials containing collagen, despite being constituents of bone matrix and have good biocompatibility, are the most studied. One way of improving these materials would be the incorporation of nanoparticles of inorganic compounds considered antimicrobials. An example of this class of compounds are silver nanoparticles. Thus, the objective of this project is the development of materials, that are potentially applicable as regenerators of bone accelerating the osteogenesis process, through possible combinations of organic and inorganic phases at the nanometer scale, resulting in obtaining of materials hybrids with bioactive properties and controllable structures. Accordingly, these materials must be bioactive to stimulate the growth of hydroxyapatite mimicking the regeneration of bone tissue and, in addition, should have a compatible degradation rate with the repair rate of this tissue. For this, it will be prepared and characterized of self-supporting membranes consist of biopolymers reinforced with calcium phosphate doped with silver nanoparticles. The incorporation of the inorganic phase consisting of calcium phosphate in the organic matrix will be through three different methodologies: (1) precipitation in locus in the interstices of the polymer matrix; (2) Addition of previously synthesized nanoparticles; (3) Addition of bovine hydroxyapatite in the polymer matrix. In the first part of this project, the hybrid biopolymer membranes will be obtained and, then, will be characterized regarding to its composition using infrared spectroscopy (FTIR) and microscopically by scanning electron microscopy techniques (SEM). The crystalline structure of these membranes will be assessed using X-ray diffraction. The strength of the material is evaluated by mechanical testing in which the analysis resistance is given by the Young's modulus obtained from the slope of the curve stress-strain versus elongation. Later, it will be characterized regarding surface energy and wettability using contact angle measurements. The best results regarding the composition, morphology, strength and surface properties are selected for tests in the culture of osteoblasts in vitro. The absorption of the samples will be studied by immersing the membrane obtained before and after modification with biomineral simulated body fluid (SBF). (AU)