Assessment of Staphylococcus Aureus growth on biocompatible 3D printed materials

The customizability of 3D printing allows for the manufacturing of personalized medical devices such as laryngectomy tubes, but it is vital to establish the biocompatibility of printing materials to ensure that they are safe and durable. The goal of this study was to assess the presence of S. aureus biofilms on a variety of 3D printed materials (two surgical guide resins, a photopolymer, an elastomer, and a thermoplastic elastomer filament) as compared to standard, commercially available laryngectomy tubes. C-shaped discs (15 mm in height, 20 mm in diameter, and 3 mm in thickness) were printed with five different biocompatible 3D printing materials and S. aureus growth was compared to Shiley™ laryngectomy tubes made from polyvinyl chloride. Discs of each material were inoculated with S. aureus cultures and incubated overnight. All materials were then removed from solution, washed in phosphate-buffered saline to remove planktonic bacteria, and sonicated to detach biofilms. Some solution from each disc was plated and colony-forming units were manually counted the following day. The resulting data was analyzed using a Kruskal-Wallis and Wilcoxon Rank Sum test to determine pairwise significance between the laryngectomy tube material and the 3D printed materials. The Shiley™ tube grew a median of 320 colonies (IQR 140–520), one surgical guide resin grew a median of 640 colonies (IQR 356–920), the photopolymer grew a median of 340 colonies (IQR 95.5–739), the other surgical guide resin grew a median of 431 colonies (IQR 266.5–735), the thermoplastic elastomer filament grew a median of 188 colonies (IQR 113.5–335), and the elastomer grew a median of 478 colonies (IQR 271–630). Using the Wilcoxon Rank Sum test, manual quantification showed a significant difference between biofilm formation only between the Shiley™ tube and a surgical guide resin (p = 0.018). This preliminary study demonstrates that bacterial colonization was comparable among most 3D printed materials as compared to the conventionally manufactured device. Continuation of this work with increased replicates will be necessary to determine which 3D printing materials optimally resist biofilm formation.