Effect of temperature and ultraviolet light on the bacterial kill effectiveness of antibiotic-infused 3D printed implants.

Abstract

Drug eluting 3D printed polymeric implants have great potential in orthopaedic applications since they are relatively inexpensive and can be designed to be patient specific thereby providing quality care. Fused Deposition Modeling (FDM) and Stereolithography (SLA) are among the most popular techniques available to print such polymeric implants. These techniques facilitate introducing antibiotics into the material at microscales during the manufacturing stage and subsequently, the printed implants can be engineered to release drugs in a controlled manner. However, FDM uses high temperature to melt the filament as it passes through the nozzle and SLA relies on exposure to nanoscale wavelength ultraviolet (UV) light which can adversely affect the anti-bacterial effectiveness of the antibiotics. The focus of this article is two-fold: i) Examine the effect of high temperature on the bacterial kill-effectiveness of eluted antibiotics through Polycaprolactone (PCL) based femoral implants and ii) Examine the effect of exposure to ultraviolet (UV) light on the bacterial kill-effectiveness of eluted antibiotics through femoral implants made up of a composite resin with various weight fractions of Polyethylene Glycol (PEG) and Polyethylene Glycol Diacrylate (PEGDA). Results indicate that even after exposing doxycycline, vancomycin and cefazolin at different temperatures between 20oC and 230oC, the antibiotics did not lose their effectiveness (kill radius of at least 0.85 cm). For doxycycline infused implants exposed to UV light, it was seen that a resin with 20 % PEGDA and 80 % PEG had the highest efficacy (1.8 cm of kill radius) and the lowest efficacy was found in an implant with 100 % PEGDA (1.2 cm of kill radius).