3D-printing on human acellular dermis for chest wall reconstructions-an in vitro and in ovo study

Massive bone or tissue defects caused by trauma, tumors or infections are a frequently occurring clinical problem. Novel biomaterials combined with new technologies offer new treatment options especially regarding reconstruction of bone and tissue. Aim of this study was to establish the stable and biocompatible combination of decellularized human dermis with a stable polymer via three-dimensional (3D) printing.

Polylactide (PLA) models were 3D-printed onto human acellular dermis (hAD) membranes using FreeCAD (computer-aided design) software for modeling and Ultimaker 2+ for printing. Cytotoxicity was assessed using L929 fibroblast cells in an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid (MTT) assay analogue to DIN EN ISO 10993-5 guidelines. Laser microtome sectioning was performed to enable histological analysis involving hematoxylin-eosin (HE) staining for tissue morphology assessment. The chorioallantoic membrane (CAM) assay was conducted on fertilized chicken eggs to evaluate cytotoxic effects and vascular ingrowth, by microscopic imaging.

PLA was successfully 3D-printed onto hAD, forming a stable bond. After 72 hours of incubation in PBS, the printed structure remained securely attached. Histological analysis confirmed the integrity of the collagen structure after printing with high temperatures, with only slight compression in the top layer of the hAD. Cytotoxicity testing according to ISO 10993-5 showed no significant reduction in cell viability (83%), thereby demonstrating biocompatibility. The CAM assay demonstrated vascular integration, with vessels forming around and connecting to the hybrid material.

The successful 3D printing of PLA onto hAD resulted in a stable hybrid material with preserved structural integrity and good fluid resistance. Histological and cytotoxicity analyses confirmed biocompatibility, while the CAM assay demonstrated vascular integration. These findings suggest that the hAD-PLA composite holds potential for biomedical applications, particularly in tissue engineering.