Usal, T. D., Yesiltepe, M., Yucel, D., Sara, Y., and Hasirci, V. (2021). Fabrication of a 3D Printed PCL Nerve Guide: In Vitro and In Vivo Testing. Macromolecular Bioscience, 2100389. DOI: 10.1002/mabi.202100389

Nerve guides are medical devices designed to guide proximal and distal ends of injured peripheral nerves in order to assist regeneration of the damaged nerves. A 3D-printed polycaprolactone (PCL) nerve guide using an aligned gelatin-poly(3-hydroxybutyrate-co-3-hydroxyvalerate) electrospun mat, seeded with PC12 and Schwann cells (SCs) is produced. During characterization with microCT and SEM porosity (55%), pore sizes (675 ± 40 µm), and fiber diameters (382 ± 25 µm) are determined. Electrospun fibers have degree of alignment of 7°, indicating high potential for guidance. On Day 14, PC12 cells migrated from proximal to distal end of nerve guide when SCs are seeded on the guide. After 28 days, over 95% of PC12 are alive and aligned. PC12 cells express early differentiation marker beta-tubulin 10 times more than late marker NeuN. In a 10 mm rat sciatic nerve injury, functional recovery evaluated by using static sciatic index (SSI) is observed in mat-free guides and guides containing mat and SCs. Nerve conduction velocities are also improved in these groups. Histological stainings showed tissue growth around nerve guides with highest new tissue organization being observed with mat and cell-free guides. These suggest 3D-printed PCL nerve guides have significant potential for treatment of peripheral nerve injuries.

Hasırcı, V., Yucel, D., Kenar, H., Selamet, H., Basoz, D., Cam, N., Kıratlı, K. (2022). Developments in the application of three dimensional printing in the medical field, TOTBİD Dergisi, 21, 102-111. DOI: 10.5578/totbid.dergisi.2022.16 (Article Language: Turkish)

In the medical field, Biomaterials along with the contribution of the tissue engineering, makes significant contributions to the quality of life. The form and the proper fit of the medical devices developed (artificial tissues, implants, et cetera) and placed in the human body are as important as their materials because while the tissue is regenerating and when the implant gets covered with the newly formed tissue large gaps between the tissue and the implants are not desirable. If attention is not paid to this, tissue regeneration may not take place satisfactorily or the implant may not be securely fitted at the site of application. One of the newly developed technologies is three dimentional (3D) printing or additive manufacturing and is being rapidly adapted to the biomaterials field with just the correct approach to prevent this potential problem because the inner and outer architecture of the 3D printed products mimic the original very accurately. Through this method the life cycle of the patients are not disturbed by problems arising from product misfits. In this review information along with examples from dental, orthopedic and ophthalmologic fields are presented.

Atila, D., Chen, C. Y., Lin, C. P., Lee, Y. L., Hasirci, V., Tezcaner, A., and Lin, F. H. (2022). In vitro evaluation of injectable Tideglusib-loaded hyaluronic acid hydrogels incorporated with Rg1-loaded chitosan microspheres for vital pulp regeneration. Carbohydrate Polymers, 278, 118976. DOI: 10.1016/j.carbpol.2021.118976

Injectable systems receive attention in endodontics due to the complicated and irregular anatomical structure of root canals. Here, injectable Tideglusib (Td)-loaded hyaluronic acid hydrogels (HAH) incorporated with Rg1-loaded chitosan microspheres (CSM) were developed for vital pulp regeneration, providing release of Td and Rg1 to trigger odontoblastic differentiation of human dental pulp stem cells (DPSC) by Td and vascularization of pulp by Rg1. The optimal concentrations were determined as 90 nM and 50 μg/mL for Td and Rg1, and loaded in HA and CSM in HAH, respectively. Odontogenic (COL1A1, ALP, OCN, Axin-2, DSPP, and DMP1) and angiogenic (VEGFA, VEGFR2, and eNOS) differentiation of DPSC cultured in the presence of hydrogels was shown at gene expression level. Our results suggest that our injectable hydrogel formulation has potential to improve strategies for vital pulp regeneration. In vivo evaluations are needed to test the feasibility and potential of these hydrogels for vital pulp regeneration.