Produção de fitas cerâmicas à base de TCP/PVA reticuladas com ácido cítrico via tape casting

Abstract

Tricalcium phosphate (TCP) has been extensively investigated for its chemical and biological similarity to bone tissue and cell adhesion. However, it degrades a little faster than bone regeneration and its mechanical resistance is relatively low. To overcome these shortcomings, much research has been done to obtain composites formed by TCP and polymers to optimize mechanical properties. Among these polymers, polyvinyl alcohol (PVA) is a synthetic material that is biocompatible. However, its rapid degradability interferes negatively in osteogenesis, due to a reduced time of interaction between the material and the bone. A promising alternative to this is the use of citric acid as a crosslinking agent. Infections are considered to be one of the most serious complications during the postoperative period. One answer to this problem is the use of systems containing silver ions because they have strong bactericidal effects. Regarding the methods to produce films, tape casting technique has the advantage of producing thin films of controlled thickness. Thus, the objective of this work is to obtain ceramic tapes based on TCP, PVA, citric acid as a crosslinking agent and silver nanoparticles through the tape casting method. The slurries were analyzed through rheological test and the films were submitted to X-ray diffraction (XRD), X-ray fluorescence (FRX), water uptake, scanning electron microscopy (SEM), thermal analysis (ATG and ATD), bioactivity and cytotoxicity assays. The results showed that the suspensions presented pseudoplastic behavior, suitable for the process via tape casting. The tapes’ XRD patterns revealed the presence of β-TCP phase and FRX analysis confirmed the presence of the silver element for compositions containing the antimicrobial agent. The degree of swelling, thermal analysis and MEV images validated PVA crosslinking, as samples containing citric acid showed to be more resistant to water and heat treatment, in addition to having a denser microstructure. Biocompatibility analyzes confirmed that the material was bioactive and non-toxic to bone cells, suitable for use in bone dressings.