(165t) Surface Modification at Nanoscale for Polyether-Ether-Ketone (PEEK) to Improve Bone Osseointegration Properties

Polyether-ether-ketone (PEEK) is a polyatomic semi-crystalline aromatic thermoplastic polymer with high-temperature resistance. PEEK is also chemically inert and has excellent mechanical strength. Due to these remarkable properties, PEEK is increasingly being used in many fields, including biomedical applications such as orthopedic and dental implants. However, being bio-inert, PEEK has poor bone osseointegration property that prevents its full usage in clinical applications. The surface modification at nanoscale offers an effective way to improve the osseointegration of PEEK with the bone. In this study, we modified the surface of PEEK at a nanoscale using chemical etching methods. PEEK sheets with dimensions (6 ”X 6” X 1/16”) was cut into smaller sections of dimensions of 0.7 mm X 0.7 mm using a band saw. Chemical etching was performed using 98% sulfuric acid for 30 seconds for three treatment groups. In sum 4 groups of PEEK were ultimately prepared 1) Control (Untreated) 2) Treatment 1 (Etched with Sulfuric acid and washed with distilled water), 3) Treatment 2 ( Etched with Sulfuric acid and washed with Acetone and distilled water). Treatment 3 ( Etched with Sulfuric acid and washed with 4 wt % Sodium Hydroxide and distilled water). Surface characterization of different groups was evaluated for wettability by measuring the contact angles, roughness using a profilometer, and topology and porosity using a scanning electron microscope (SEM). Further in-vitro cellular behavior will be studied using cell viability and proliferation assays. All the treatment groups exhibited poor wettability properties irrespective of the treatment based on the measured contact angles. The contact angle of the untreated PEEK surface was 71.8 ± 5.3^o. This was significantly lower (P<0.05) than the treatment groups' measured contact angles with Group 2: 99.8 ± 8.6^o; Group 3: 101.8 ± 13.2^o; and Group 4: 111.2 ± 15.0^o. Untreated group PEEK control surfaces (Group 1) exhibited a polished surface with an average nano roughness of 7.22 ± 0.001 nm, while treated groups exhibited nano roughness in the range of 100 to 160 nm and was significantly higher than the control group (P<0.05). This was further confirmed by the SEM images that revealed flat smooth surfaces for the untreated group. In contrast, a porous structure with pores size of 0.7 ± 0.1 µm was observed in the treated group. In conclusion, our preliminary results indicate that we successfully modified the surface of PEEK at the nanoscale, potentially enhancing bone osseointegration properties for PEEK material.