## 1 Introduction
However, complex operation process is thus necessary to be employed in the applications of printing PEEK samples with the 3 DP method. Another 3D printing technology based on the SLS method is a rapid method for the preparation of complex 3D supports. It uses a focused high-energy source (such as laser energy source) to make metal or PEEK materials melt and to rebuild a 3D support with melting metal or PEEK material in the 3D printer. However, high equipment costs and high energy requirements of 3D printers based on the SLS method are its major problems. Although some possible printing parameters for commerical 3D printers based on the fused deposition modeling were reported for the preparation of PEEK disks [5], the failure percentage for PEEK samples prepared using the commerical 3D printer based on fused deposition modeling is still too high (failure percentage of around 20%). Optimal printing parameters and the design of a traditional 3D printer have to be remodified in order to obtain fast and precise printing for the preparation of the PEEK supports. Even if these complex 3D supports for bone or tissue engineering applications can be obtained using a 3D printer, another important issue for the clinical requirement of orthopedic suffers is its antibacterial property. In the clinical treatment of orthopedic suffers, implant-associated infection is a major complication in orthopedic surgery. According to the report proposed by [PERSON] et al. (2017) [14], infection rates of orthopedic surgery are in the range of 1-5%. It increases exponentially for immunocompromisedpatients. The possibility of infection for orthopedic surgery after revision surgery can increase to as high as 5-40%, which indicates that prevention of implant-associated infection is important. Local injection of high doses of antibiotic agent such as ampicillin sodium salt into the human body is thus necessary to prevent implant-associated infection. However, it may result in the waste of antibiotic agents injected into the human body. Suitable antibacterial activity of these implants may reduce the waste of usage of antibiotic agents using local injection. Generally, the recovery time for a complex orthopedic suffer is around one month. Stable local concentration of antibiotic agents near the implant in a human body of higher than the minimum inhibition concentration (MIC; 90) is thus necessary for clinical requirements. [PERSON] et al. (2017) [14] prepared the porous Ti-based implants with surface coating of silver ions and vancomycin salt with chitosan/gelatin applied by electrophoretic deposition in order to improve the antibacterial behaviors of Ti-based implants. The antibacterial behaviors of their samples can continue around 21 days using the release of silver ions and vancomycin salt into the buffer solution. Although the antibacterial behavior of metal ions (e.g., silver, zinc, or ferrous ions) or natural compounds (e.g., Chlorogenic acid) were employed with the implants in the literature [14; 15; 16; 17; 18; 19], release of these metal ions in the human body may result in safety issues in the human body. In our previous study, the ZnO nanotube arrays grown on the PEEK disks with direct absorption of the antibiotic agent (vancomycin or am ampicillin sodium salt) were employed in order to test their antibacterial behavior and to reduce the cytotoxicity of silver ions [5]. The results showed that the concentrations of antibiotic agents released from our samples into the buffer solution were higher than MIC 90 for _Staphylococcus aureus_ (_S. aureus_) and can continue up to 100 h (around 5 five days). Even though the PEEK samples with suitable antibacterial property were reported, their antibacterial behaviors are not enough to meet the clinical requirements (around one month) of orthopedic suffers. Optimal printing parameters for the preparation of PEEK substrates using 3D printing technology based on the fused deposition modeling are not enough for future industrial or clinical applications.