Introduction: 3D printing is becoming an important technology in the field of tissue engineering and regenerative medicine (TERM). In order to become fully adopted in the field, it becomes important to easily develop and process novel materials which can be employed through this technology. This work aims at developing a simplified method for preparing advanced materials for fused deposition modelling-based 3D printing. In this particular study a dexamethasone-releasing material was developed, whose bioerosion rate and dexamethasone release profiles can be tuned according to specific requirements in bone TERM applications. Materials and Methods: Homogeneous polycaprolactone (PCL):pokwamine (PLX) powder blends (100:0,90:10 and 80:20 wt.%) were prepared by mixing in a turbula. Dexamethasone In powder form was added to part of the replicates. These various blends were converted into the form of filament by means of a melt-based processing methodology. These filaments were then fed into a Fused Deposition Modelling-based 3D printer to fabricate 3D porous scaffolds. The scaffolds of various compositions were analyzed and compared in terms of porosity and degradation rate for a period of 3 months. The release profile of the dexamethasone was periodically analyzed spectrophotometrically following immersion of the scaffolds into fixed volumes of PBS. The osteoinductivity of the 3D printed scaffolds was evaluated in vitro by seeding human mesenchymal stem cells (hMSCs) and periodical analysis of ALP activity, DNA content, morphology and viability by confocal microscopy at 7,14 and 21 days of culture. Results and Discussion: Several blend ratios of PCLPLX were converted into homogeneous filaments and further 3D printed in the form of 3D porous, homogeneous and reproducible scaffolds. According to what was expected a priori, higher concentrations of PLX generated greater weight loss due to the greater erosion rate of PLX. Higher concentrations of PLX resulted as well in a lower degree of sub-micrometric porosity given that PLX was able to fill the pores formed by PCL. The final dexamethasone release profiles resulted as a balance between the degree of porosity and the rate of degradation. 80:20 samples possessed greater degradation rate but lower porosity while 100:0 samples possessed greater porosity but slower degradation rate. As a result from this combination, 90:10 samples were the ones with greater drug release due to a combination of sufficient porosity and degradation rate. In vitro cultures showed a greater overall ALP activity for 90:10 samples, followed by 100:0 and 80:20 samples. Cellular proliferation in an initial stage. Conclusions: In this work it was show that it is possible to prepare 3D printable materials in an easy and inexpensive way. The processing into a filament form streamlines the employment into 3D printing. The obtained materials can possess advanced features such as the controlled release of drugs, as shown in this study where various PCL/PLX blend formulations with varying dexamethasone release profiles resulted in varying in vitro osteogenic activities.
展开▼
