In this study, an attempt was made to develop bi-functional constructs serving both as scaffolds and potential delivery systems for application in neural tissue engineering. The constructs were prepared in two steps. In the first step, the bulks of poly (L-lactic acid) (PLLA) in 1, 4-dioxane/water (87:13) were fabricated using liquid-liquid thermally induced phase separation technique. In the next step, the prepared bulks were coated with chitosan nanoparticles produced by two different techniques of ultrasonication and ionic gelation by grafting-coating technique. In ultrasonication technique, the chitosan solution (2 mg/mL) in acetic acid/sodium acetate buffer (90:10) was irradiated by an ultrasound generator at 20 kHz and power output of 750 W for 100 s. In ionic gelation technique, the tripolyphosphate in water solution (1 mg/mL) was added to the same chitosan solution. The physicochemical properties of the products were characterized by Scanning Electron Microscopy, Attenuated Total Reflection Fourier Transform-Infrared, liquid displacement technique, contact angle measurement, compressive and tensile tests, as well as zeta potential and particle size analysis using dynamic light scattering. Moreover, the cell proliferation and attachment on the scaffolds were evaluated through human glioblastoma cell line (U-87 MG) and human neuroblastoma cell line [BE (2)-C] culture respectively. The results showed that the samples coated with chitosan nanoparticles prepared by ultrasonication possessed enhanced hydrophilicity, biodegradation and cytocompatibility compared with pure PLLA and PLLA coated with chitosan nanoparticles prepared by ionic gelation. This study suggests successful nanoparticles-scaffold systems which can act simultaneously as potential delivery systems and tissue engineering scaffolds.
Cell Line ; Cell Proliferation ; Chitosan* ; Dynamic Light Scattering ; Glioblastoma ; Humans ; Hydrophobic and Hydrophilic Interactions ; Microscopy, Electron, Scanning ; Nanoparticles* ; Neuroblastoma ; Particle Size ; Tissue Engineering ; Ultrasonography ; Water

BACKGROUND: In the aftermath of bone injuries, such as cranium and sternum, bone wax (BW) is used to control bleeding from the bone surfaces during surgery. Made up of artificial substances, however, it is associated with many complications such as inflammation, increased risk for infection, and bone repair delay. We, therefore, in this study set out to design and evaluate a novel BW without the above-mentioned side-effects reported for other therapies. METHODS: The pastes (new BW(s)) were prepared in the laboratory and examined by MTT, MIC, MBC, and degradability tests. Then, 60 adult male Wistar rats, divided into six equal groups including chitosan (CT), CT-octacalcium phosphate (OCP), CT-periostin (Post), CT-OCP-Post, Control (Ctrl), and BW, underwent sternotomy surgery. Once the surgeries were completed, the bone repair was assessed radiologically and thereafter clinically in vivo and in vitro using CT-scan, H&E, ELISA, and qRT-PCR. RESULTS: All pastes displayed antibacterial properties and the CT-Post group had the highest cell viability compared to the control group. In contrast to the BW, CT-Post group demonstrated weight changes in the degradability test. In the CT-Post group, more number of osteocyte cells, high trabeculae percentage, and the least fibrous connective tissue were observed compared to other groups. Additionally, in comparison to the CT and Ctrl groups, higher alkaline phosphatase activity, as well as decreased level of serum tumor necrosis factor-a, interleukin-6, and OCN in the CT-Post group was evident. Finally, Runx2, OPG, and RANKL genes’ expression was significantly higher in the CT-Post group than in other groups. CONCLUSION Our results provide insights into the desirability of pastes in terms of cellular viability, degradability, antibacterial properties, and surgical site restoration compared to the BW group. Besides, Periostin could enhance the osteogenic properties of bone tissue defect site.