abstract
Synthetic physiological fluids are currently used as a first in vitro bioactivity assessment for bone grafts. Our understanding about the interactions taking place at the fluid-implant interface has evolved remarkably during the last decade, and does not comply with the traditional International Organization for Standardization/final draft International Standard 23317 protocol in purely inorganic simulated body fluid. The advances in our knowledge point to the need of a true paradigm shift toward testing physiological fluids with enhanced biomimicry and a better understanding of the materials' structure-dissolution behavior. This will contribute to "upgrade" our vision of entire cascades of events taking place at the implant surfaces upon immersion in the testing media or after implantation. Starting from an osteoinductive bioglass composition with the ability to alleviate the oxidative stress, thin bioglass films with different degrees of polymerization were deposited onto titanium substrates. Their biomineralization activity in simulated body fluid and in a series of new inorganic-organic media with increasing biomimicry that more closely simulated the human intercellular environment was compared. A comprehensive range of advanced characterization tools (scanning electron microscopy; grazing-incidence X-ray diffraction; Fourier-transform infrared, micro-Raman, energy-dispersive, X-ray photoelectron, and surface-enhanced laser desorption/ionization time-of-flight mass spectroscopies; and cytocompatibility assays using mesenchymal stem cells) were used. The information gathered is very useful to biologists, biophysicists, clinicians, and material scientists with special interest in teaching and research. By combining all the analyses, we propose herein a step forward toward establishing an improved unified protocol for testing the bioactivity of implant materials.
keywords
SIMULATED BODY-FLUID; IN-VITRO BIOACTIVITY; DRUG-RELEASE PROPERTY; THIN-FILMS; PROTEIN ADSORPTION; APATITE-FORMATION; MECHANICAL-PROPERTIES; DISSOLUTION BEHAVIOR; BONE REGENERATION; LOW-TEMPERATURE
subject category
Science & Technology - Other Topics; Pharmacology & Pharmacy
authors
Popa, AC; Stan, GE; Husanu, MA; Mercioniu, I; Santos, LF; Fernandes, HR; Ferreira, JMF
our authors
Hugo Alexandre Gonçalves da Rocha Fernandes
Junior Researcher
José Maria da Fonte Ferreira
Retired ProfessorGroups
G3 - Electrochemical Materials, Interfaces and Coatings
G5 - Biomimetic, Biological and Living Materials
acknowledgements
ACP, GES, and MAH are grateful for the financial support of the Romanian National Authority for Scientific Research and Innovation, CNCS-UEFISCDI, in the framework of projects PN-II-RU-TE-2011-4-0164 (contract 49/2011), PN-II-RU-TE-2014-4-0180 (contract 73/2015), and Core Programme PN 16 48-3/2016. The support of CICECO Aveiro Institute of Materials (Ref UID/CTM/50011/2013), funded by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020), and the Portuguese Foundation for Science and Technology (FCT) is acknowledged. The authors thank Dr B Almeida, Dr M Enculescu, and Dr F Miculescu for the help provided with some of the SEM analyses.