(T1030-12-79) Extrusion of Customized PLLA Filaments Reinforced with Zinc Oxide Nanoparticles for Fabrication of 3D Anti-tumor Printlets

Purpose: Breast cancer counted to be the second most frequently abundant cancer type in women globally. In addition, it is responsible for 3-5% of female deaths each year. Most traditional chemotherapeutic and anti-tumor agents possess significant drawbacks owing to their side effects including hair loss, nausea, and vomiting, etc. On the other hand, zinc oxide nanoparticles (ZnO NPs) which has proven to be a potent anti-tumor agent have been found to be biocompatible and capable of selectively attacking tumor cells through their affinity towards reactive oxygen species (ROS). Furthermore, localized treatment has proven its effeciency in limiting traditional chemotherapy drawbacks^1,2. Hence, this study aims at fabrication of 3D printlets using customized PLLA filaments reinforced with ZnO NPs using on top bench extruder.

Methods: Zinc oxide nanoparticles (ZnO NPs) were optimized and prepared through sol-gel technique, a wet chemical method. Afterwards, their properties were thoroughly analyzed using TEM imaging, UV spectroscopy, Fourier Transform Spectroscopy (FTIR) and X-ray diffraction (XRD). Then, ZnO NPs were mixed with PLLA pellets, ground together before being extruded using on top bench extruder to fabricate customized filaments through which ZnO NPs were subjected to situ calcination process. Using an FDM 3D printer, the resultant customized filaments were used to fabricate 3D printlets in the form of round-shaped discs that can be implanted after breast cancer surgeries in order prevent cancer recurrence.

Results: TEM analysis of ZnO NPs demonstrated in Figure 1a shows that the developed nanoparticles possess nearly spherical or semi hexagonal shape with a size range of 15-20nm. This was found to be in a good accordance with XRD results as shown in Figure 1b. Furthermore, the synthesis of zinc oxide was further confirmed through FTIR spectrum illustrated in Figure 1c, where the characteristic peaks at 400 cm^-1 and 2888 cm^-1 showing Zn – O stretching, and C – H bonds vibrations, respectively. In addition, a broad band appearing at 3425 cm^-1 is attributed to the abundance of O – H groups stretching. Finally, UV spectrum demonstrated in Figure 1d showed an excitonic peak detected at 362 nm indicating the formation of ZnO NPs in the nanoscale range rather than bulk ZnO which show peak at around 380 nm. In a following stage, customized PLLA filaments reinforced with ZnO nanoparticles shown in Figure 2a were successfully extruded using a top bench extruder. Through the extrusion process, ZnO NPs underwent in-situ calcination. The fabricated filaments were then used in 3D printing in to prepare circular 3D printlets as shown in Figure 2b. The printlets were developed to be implanted after breast cancer surgeries to serve as promising carrier for chemotherapy and/or growth factors in order to prevent cancer recurrence and restore damaged tissues, respectively. Finally, cytotoxicity tests were conducted using normal fibroblasts and breast cancer cell lines as shown in Figure 3a and 3b, respectively. Both unloaded and loaded printlets were tested which confirmed the selective anti-cancer activity of the developed printlets towards cancer cells while showing high biocompatibility towards normal cells.

Conclusion: ZnO Reinforced PLLA filaments have been fabricated successfully and can be used to develop customized implantable 3D printlets for selective breast cancer treatment and targeting.

References: (1) Siegel RL, Miller KD, Jemal A. CA Cancer J Clin. 2020:70(1): 7-30. (2) Blaya B, et al. Inflamm Allergy - Drug Targets. 2010: 9(3): 146-157

Acknowledgements: This work was supported by a grant Science, Technology & Innovation Funding Authority, Egypt, Project No. 45769.

Figure 1. Characterization of ZnO NPs: a) TEM imaging, b) XRD, c) FTIR spectrum, and d) UV spectrum.

Figure 2. a) ZnO Reinforced PLLA Filament, and b) ZnO Reinforced 3D Printlet.

Figure 3. Cytotoxicity of plain and loaded Printlets towards: a) Normal fibroblasts, and b) Breast cancer cells.