ABSTRACT
Porous 3-D scaffolds consisting of gelatine and Si-doped hydroxyapatite were fabricated at room temperature by rapid prototyping. Microscopic characterization revealed a highly homogeneous structure, showing the pre-designed porosity (macroporosity) and a lesser in-rod porosity (microporosity). The mechanical properties of such scaffolds are close to those of trabecular bone of the same density. The biological behavior of these hybrid scaffolds is greater than that of pure ceramic scaffolds without gelatine, increasing pre-osteoblastic MC3T3-E1 cell differentiation (matrix mineralization and gene expression). Since the fabrication process of these structures was carried out at mild conditions, an antibiotic (vancomycin) was incorporated in the slurry before the extrusion of the structures. The release profile of this antibiotic was measured in phosphate-buffered saline solution by high-performance liquid chromatography and was adjusted to a first-order release kinetics. Vancomycin released from the material was also shown to inhibit bacterial growth in vitro. The implications of these results for bone tissue engineering applications are discussed.
Subject(s)
Bone Regeneration , Drug Delivery Systems/methods , Durapatite/chemistry , Gelatin/chemistry , Silicon/chemistry , Tissue Scaffolds/chemistry , Animals , Anti-Bacterial Agents/pharmacology , Bone Regeneration/drug effects , Cell Line , Cell Proliferation/drug effects , Hydrophobic and Hydrophilic Interactions , Materials Testing , Mice , Microbial Sensitivity Tests , Particle Size , Porosity , Spectroscopy, Fourier Transform Infrared , Stress, Mechanical , Sus scrofa , Vancomycin/pharmacology , X-Ray DiffractionABSTRACT
Porous scaffolds are widely tested materials used for various purposes in tissue engineering. A critical feature of a porous scaffold is its ability to allow cell migration and growth on its inner surface. Up to now, there has not been a method to locate live cells deep inside a material, or in an entire structure, using real-time imaging and a non-destructive technique. Herein, we seek to demonstrate the feasibility of the magnetic resonance imaging (MRI) technique as a method to detect and locate in vitro non-labelled live cells in an entire porous material. Our results show that the use of optimized MRI parameters (4.7 T; repetition time = 3000 ms; echo time = 20 ms; resolution 39 × 39 µm) makes it possible to obtain images of the scaffold structure and to locate live non-labelled cells in the entire material, with a signal intensity higher than that obtained in the culture medium. In the current study, cells are visualized and located in different kinds of porous scaffolds. Moreover, further development of this MRI method might be useful in several three-dimensional biomaterial tests such as cell distribution studies, routine qualitative testing methods and in situ monitoring of cells inside scaffolds.
